Table Of Contents¶
Welcome to Tastypie!¶
Tastypie is an webservice API framework for Django. It provides a convenient, yet powerful and highly customizable, abstraction for creating REST-style interfaces.
Getting Started with Tastypie¶
Tastypie is a reusable app (that is, it relies only on it’s own code and focuses on providing just a REST-style API) and is suitable for providing an API to any application without having to modify the sources of that app.
Not everyone’s needs are the same, so Tastypie goes out of its way to provide plenty of hooks for overriding or extending how it works.
Note
If you hit a stumbling block, you can join #tastypie on irc.freenode.net to get help.
This tutorial assumes that you have a basic understanding of Django as well as how proper REST-style APIs ought to work. We will only explain the portions of the code that are Tastypie-specific in any kind of depth.
For example purposes, we’ll be adding an API to a simple blog application. Here is myapp/models.py:
from tastypie.utils.timezone import now
from django.contrib.auth.models import User
from django.db import models
from django.template.defaultfilters import slugify
class Entry(models.Model):
user = models.ForeignKey(User)
pub_date = models.DateTimeField(default=now)
title = models.CharField(max_length=200)
slug = models.SlugField()
body = models.TextField()
def __unicode__(self):
return self.title
def save(self, *args, **kwargs):
# For automatic slug generation.
if not self.slug:
self.slug = slugify(self.title)[:50]
return super(Entry, self).save(*args, **kwargs)
With that, we’ll move on to installing and configuring Tastypie.
Installation¶
Installing Tastypie is as simple as checking out the source and adding it to your project or PYTHONPATH.
- Download the dependencies:
- Python 2.4+
- Django 1.0+ (tested on Django 1.1+)
- mimeparse 0.1.3+ (http://code.google.com/p/mimeparse/)
- Older versions will work, but their behavior on JSON/JSONP is a touch wonky.
- dateutil (http://labix.org/python-dateutil)
- OPTIONAL - lxml (http://lxml.de/) if using the XML serializer
- OPTIONAL - pyyaml (http://pyyaml.org/) if using the YAML serializer
- OPTIONAL - uuid (present in 2.5+, downloadable from http://pypi.python.org/pypi/uuid/) if using the ApiKey authentication
Note
Once tastypie reaches version 1.0, it will become officially available on PyPI. Once that is the case, a sudo pip install tastypie or sudo easy_install tastypie should be available.
Configuration¶
The only mandatory configuration is adding 'tastypie' to your INSTALLED_APPS. This isn’t strictly necessary, as Tastypie has only two non-required models, but may ease usage.
You have the option to set up a number of settings (see Tastypie Settings) but they all have sane defaults and are not required unless you need to tweak their values.
Creating Resources¶
REST-style architecture talks about resources, so unsurprisingly integrating with Tastypie involves creating Resource classes. For our simple application, we’ll create a file for these in myapp/api.py, though they can live anywhere in your application:
# myapp/api.py
from tastypie.resources import ModelResource
from myapp.models import Entry
class EntryResource(ModelResource):
class Meta:
queryset = Entry.objects.all()
resource_name = 'entry'
This class, by virtue of being a ModelResource subclass, will introspect all non-relational fields on the Entry model and create it’s own ApiFields that map to those fields, much like the way Django’s ModelForm class introspects.
Note
The resource_name within the Meta class is optional. If not provided, it is automatically generated off the classname, removing any instances of Resource and lowercasing the string. So EntryResource would become just entry.
We’ve included the resource_name attribute in this example for clarity, especially when looking at the URLs, but you should feel free to omit it if you’re comfortable with the automatic behavior.
Hooking Up The Resource(s)¶
Now that we have our EntryResource, we can hook it up in our URLconf. To do this, we simply instantiate the resource in our URLconf and hook up its urls:
# urls.py
from django.conf.urls.defaults import *
from myapp.api import EntryResource
entry_resource = EntryResource()
urlpatterns = patterns('',
# The normal jazz here...
(r'^blog/', include('myapp.urls')),
(r'^api/', include(entry_resource.urls)),
)
Now it’s just a matter of firing up server (./manage.py runserver) and going to http://127.0.0.1:8000/api/entry/?format=json. You should get back a list of Entry-like objects.
Note
The ?format=json is an override required to make things look decent in the browser (accept headers vary between browsers). Tastypie properly handles the Accept header. So the following will work properly:
curl -H "Accept: application/json" http://127.0.0.1:8000/api/entry/
But if you’re sure you want something else (or want to test in a browser), Tastypie lets you specify ?format=... when you really want to force a certain type.
At this point, a bunch of other URLs are also available. Try out any/all of the following (assuming you have at least three records in the database):
However, if you try sending a POST/PUT/DELETE to the resource, you find yourself getting “401 Unauthorized” errors. For safety, Tastypie ships with the authorization class (“what are you allowed to do”) set to ReadOnlyAuthorization. This makes it safe to expose on the web, but prevents us from doing POST/PUT/DELETE. Let’s enable those:
# myapp/api.py
from tastypie.authorization import Authorization
from tastypie.resources import ModelResource
from myapp.models import Entry
class EntryResource(ModelResource):
class Meta:
queryset = Entry.objects.all()
resource_name = 'entry'
authorization= Authorization()
Warning
This is now great for testing in development but VERY INSECURE. You should never put a Resource like this out on the internet. Please spend some time looking at the authentication/authorization classes available in Tastypie.
With just nine lines of code, we have a full working REST interface to our Entry model. In addition, full GET/POST/PUT/DELETE support is already there, so it’s possible to really work with all of the data. Well, almost.
You see, you’ll note that not quite all of our data is there. Markedly absent is the user field, which is a ForeignKey to Django’s User model. Tastypie does NOT introspect related data because it has no way to know how you want to represent that data.
And since that relation isn’t there, any attempt to POST/PUT new data will fail, because no user is present, which is a required field on the model.
This is easy to fix, but we’ll need to flesh out our API a little more.
Creating More Resources¶
In order to handle our user relation, we’ll need to create a UserResource and tell the EntryResource to use it. So we’ll modify myapp/api.py to match the following code:
# myapp/api.py
from django.contrib.auth.models import User
from tastypie import fields
from tastypie.resources import ModelResource
from myapp.models import Entry
class UserResource(ModelResource):
class Meta:
queryset = User.objects.all()
resource_name = 'user'
class EntryResource(ModelResource):
user = fields.ForeignKey(UserResource, 'user')
class Meta:
queryset = Entry.objects.all()
resource_name = 'entry'
We simply created a new ModelResource subclass called UserResource. Then we added a field to EntryResource that specified that the user field points to a UserResource for that data.
Now we should be able to get all of the fields back in our response. But since we have another full, working resource on our hands, we should hook that up to our API as well. And there’s a better way to do it.
Adding To The Api¶
Tastypie ships with an Api class, which lets you bind multiple Resources together to form a coherent API. Adding it to the mix is simple.
We’ll go back to our URLconf (urls.py) and change it to match the following:
# urls.py
from django.conf.urls.defaults import *
from tastypie.api import Api
from myapp.api import EntryResource, UserResource
v1_api = Api(api_name='v1')
v1_api.register(UserResource())
v1_api.register(EntryResource())
urlpatterns = patterns('',
# The normal jazz here...
(r'^blog/', include('myapp.urls')),
(r'^api/', include(v1_api.urls)),
)
Note that we’re now creating an Api instance, registering our EntryResource and UserResource instances with it and that we’ve modified the urls to now point to v1_api.urls.
This makes even more data accessible, so if we start up the runserver again, the following URLs should work:
- http://127.0.0.1:8000/api/v1/?format=json
- http://127.0.0.1:8000/api/v1/user/?format=json
- http://127.0.0.1:8000/api/v1/user/1/?format=json
- http://127.0.0.1:8000/api/v1/user/schema/?format=json
- http://127.0.0.1:8000/api/v1/user/set/1;3/?format=json
- http://127.0.0.1:8000/api/v1/entry/?format=json
- http://127.0.0.1:8000/api/v1/entry/1/?format=json
- http://127.0.0.1:8000/api/v1/entry/schema/?format=json
- http://127.0.0.1:8000/api/v1/entry/set/1;3/?format=json
Additionally, the representations out of EntryResource will now include the user field and point to an endpoint like /api/v1/users/1/ to access that user’s data. And full POST/PUT delete support should now work.
But there’s several new problems. One is that our new UserResource leaks too much data, including fields like email, password, is_active and is_staff. Another is that we may not want to allow end users to alter User data. Both of these problems are easily fixed as well.
Limiting Data And Access¶
Cutting out the email, password, is_active and is_staff fields is easy to do. We simply modify our UserResource code to match the following:
class UserResource(ModelResource):
class Meta:
queryset = User.objects.all()
resource_name = 'user'
excludes = ['email', 'password', 'is_active', 'is_staff', 'is_superuser']
The excludes directive tells UserResource which fields not to include in the output. If you’d rather whitelist fields, you could do:
class UserResource(ModelResource):
class Meta:
queryset = User.objects.all()
resource_name = 'user'
fields = ['username', 'first_name', 'last_name', 'last_login']
Now that the undesirable fields are no longer included, we can look at limiting access. This is also easy and involves making our UserResource look like:
class UserResource(ModelResource):
class Meta:
queryset = User.objects.all()
resource_name = 'user'
excludes = ['email', 'password', 'is_active', 'is_staff', 'is_superuser']
allowed_methods = ['get']
Now only HTTP GET requests will be allowed on /api/v1/user/ endpoints. If you require more granular control, both list_allowed_methods and detail_allowed_methods options are supported.
Beyond The Basics¶
We now have a full working API for our application. But Tastypie supports many more features, like:
- Authentication
- Authorization
- Caching
- Throttling
- Resources (filtering & sorting)
- Serialization
Tastypie is also very easy to override and extend. For some common patterns and approaches, you should refer to the Tastypie Cookbook documentation.
Interacting With The API¶
Now that you’ve got a shiny new REST-style API in place, let’s demonstrate how to interact with it. We’ll assume that you have cURL installed on your system (generally available on most modern Mac & Linux machines), but any tool that allows you to control headers & bodies on requests will do.
We’ll assume that we’re interacting with the following Tastypie code:
# myapp/api/resources.py
from django.contrib.auth.models import User
from tastypie.authorization import Authorization
from tastypie import fields
from tastypie.resources import ModelResource, ALL, ALL_WITH_RELATIONS
from myapp.models import Entry
class UserResource(ModelResource):
class Meta:
queryset = User.objects.all()
resource_name = 'user'
excludes = ['email', 'password', 'is_active', 'is_staff', 'is_superuser']
filtering = {
'username': ALL,
}
class EntryResource(ModelResource):
user = fields.ForeignKey(UserResource, 'user')
class Meta:
queryset = Entry.objects.all()
resource_name = 'entry'
authorization = Authorization()
filtering = {
'user': ALL_WITH_RELATIONS,
'pub_date': ['exact', 'lt', 'lte', 'gte', 'gt'],
}
# urls.py
from django.conf.urls.defaults import *
from tastypie.api import Api
from myapp.api.resources import EntryResource, UserResource
v1_api = Api(api_name='v1')
v1_api.register(UserResource())
v1_api.register(EntryResource())
urlpatterns = patterns('',
# The normal jazz here...
(r'^blog/', include('myapp.urls')),
(r'^api/', include(v1_api.urls)),
)
Let’s fire up a shell & start exploring the API!
Front Matter¶
Tastypie tries to treat all clients & all serialization types as equally as possible. It also tries to be a good ‘Net citizen & respects the HTTP method used as well as the Accepts headers sent. Between these two, you control all interactions with Tastypie through relatively few endpoints.
Warning
Should you try these URLs in your browser, be warned you WILL need to append ?format=json (or xml or yaml) to the URL. Your browser requests application/xml before application/json, so you’ll always get back XML if you don’t specify it.
That’s also why it’s recommended that you explore via curl, because you avoid your browser’s opinionated requests & get something closer to what any programmatic clients will get.
Fetching Data¶
Since reading data out of an API is a very common activity (and the easiest type of request to make), we’ll start there. Tastypie tries to expose various parts of the API & interlink things within the API (HATEOAS).
Api-Wide¶
We’ll start at the highest level:
curl http://localhost:8000/api/v1/
You’ll get back something like:
{
"entry": {
"list_endpoint": "/api/v1/entry/",
"schema": "/api/v1/entry/schema/"
},
"user": {
"list_endpoint": "/api/v1/user/",
"schema": "/api/v1/user/schema/"
}
}
This lists out all the different Resource classes you registered in your URLconf with the API. Each one is listed by the resource_name you gave it and provides the list_endpoint & the schema for the resource.
Note that these links try to direct you to other parts of the API, to make exploration/discovery easier. We’ll use these URLs in the next several sections.
To demonstrate another format, you could run the following to get the XML variant of the same information:
curl -H "Accept: application/xml" http://localhost:8000/api/v1/
To which you’d receive:
<?xml version="1.0" encoding="utf-8"?>
<response>
<entry type="hash">
<list_endpoint>/api/v1/entry/</list_endpoint>
<schema>/api/v1/entry/schema/</schema>
</entry>
<user type="hash">
<list_endpoint>/api/v1/user/</list_endpoint>
<schema>/api/v1/user/schema/</schema>
</user>
</response>
We’ll stick to JSON for the rest of this document, but using XML should be OK to do at any time.
Inspecting The Resource’s Schema¶
Since the api-wide view gave us a schema URL, let’s inspect that next. We’ll use the entry resource. Again, a simple GET request by curl:
curl http://localhost:8000/api/v1/entry/schema/
This time, we get back a lot more data:
{
"default_format": "application/json",
"fields": {
"body": {
"help_text": "Unicode string data. Ex: \"Hello World\"",
"nullable": false,
"readonly": false,
"type": "string"
},
"id": {
"help_text": "Unicode string data. Ex: \"Hello World\"",
"nullable": false,
"readonly": false,
"type": "string"
},
"pub_date": {
"help_text": "A date & time as a string. Ex: \"2010-11-10T03:07:43\"",
"nullable": false,
"readonly": false,
"type": "datetime"
},
"resource_uri": {
"help_text": "Unicode string data. Ex: \"Hello World\"",
"nullable": false,
"readonly": true,
"type": "string"
},
"slug": {
"help_text": "Unicode string data. Ex: \"Hello World\"",
"nullable": false,
"readonly": false,
"type": "string"
},
"title": {
"help_text": "Unicode string data. Ex: \"Hello World\"",
"nullable": false,
"readonly": false,
"type": "string"
},
"user": {
"help_text": "A single related resource. Can be either a URI or set of nested resource data.",
"nullable": false,
"readonly": false,
"type": "related"
}
},
"filtering": {
"pub_date": ["exact", "lt", "lte", "gte", "gt"],
"user": 2
}
}
This lists out the default_format this resource responds with, the fields on the resource & the filtering options available. This information can be used to prepare the other aspects of the code for the data it can obtain & ways to filter the resources.
Getting A Collection Of Resources¶
Let’s get down to fetching live data. From the api-wide view, we’ll hit the list_endpoint for entry:
curl http://localhost:8000/api/v1/entry/
We get back data that looks like:
{
"meta": {
"limit": 20,
"next": null,
"offset": 0,
"previous": null,
"total_count": 3
},
"objects": [{
"body": "Welcome to my blog!",
"id": "1",
"pub_date": "2011-05-20T00:46:38",
"resource_uri": "/api/v1/entry/1/",
"slug": "first-post",
"title": "First Post",
"user": "/api/v1/user/1/"
},
{
"body": "Well, it's been awhile and I still haven't updated. ",
"id": "2",
"pub_date": "2011-05-21T00:46:58",
"resource_uri": "/api/v1/entry/2/",
"slug": "second-post",
"title": "Second Post",
"user": "/api/v1/user/1/"
},
{
"body": "I'm really excited to get started with this new blog. It's gonna be great!",
"id": "3",
"pub_date": "2011-05-20T00:47:30",
"resource_uri": "/api/v1/entry/3/",
"slug": "my-blog",
"title": "My Blog",
"user": "/api/v1/user/2/"
}]
}
Some things to note:
- By default, you get a paginated set of objects (20 per page is the default).
- In the meta, you get a previous & next. If available, these are URIs to the previous & next pages.
- You get a list of resources/objects under the objects key.
- Each resources/object has a resource_uri field that points to the detail view for that object.
- The foreign key to User is represented as a URI by default. If you’re looking for the full UserResource to be embedded in this view, you’ll need to add full=True to the fields.ToOneField.
If you want to skip paginating, simply run:
curl http://localhost:8000/api/v1/entry/?limit=0
Be warned this will return all objects, so it may be a CPU/IO-heavy operation on large datasets.
Let’s try filtering on the resource. Since we know we can filter on the user, we’ll fetch all posts by the daniel user with:
curl http://localhost:8000/api/v1/entry/?user__username=daniel
We get back what we asked for:
{
"meta": {
"limit": 20,
"next": null,
"offset": 0,
"previous": null,
"total_count": 2
},
"objects": [{
"body": "Welcome to my blog!",
"id": "1",
"pub_date": "2011-05-20T00:46:38",
"resource_uri": "/api/v1/entry/1/",
"slug": "first-post",
"title": "First Post",
"user": "/api/v1/user/1/"
},
{
"body": "Well, it's been awhile and I still haven't updated. ",
"id": "2",
"pub_date": "2011-05-21T00:46:58",
"resource_uri": "/api/v1/entry/2/",
"slug": "second-post",
"title": "Second Post",
"user": "/api/v1/user/1/"
}]
}
Where there were three posts before, now there are only two.
Getting A Detail Resource¶
Since each resource/object in the list view had a resource_uri, let’s explore what’s there:
curl http://localhost:8000/api/v1/entry/1/
We get back a similar set of data that we received from the list view:
{
"body": "Welcome to my blog!",
"id": "1",
"pub_date": "2011-05-20T00:46:38",
"resource_uri": "/api/v1/entry/1/",
"slug": "first-post",
"title": "First Post",
"user": "/api/v1/user/1/"
}
Where this proves useful (for example) is present in the data we got back. We know the URI of the User associated with this blog entry. Let’s run:
curl http://localhost:8000/api/v1/user/1/
Without ever seeing any aspect of the UserResource & just following the URI given, we get back:
{
"date_joined": "2011-05-20T00:42:14.990617",
"first_name": "",
"id": "1",
"last_login": "2011-05-20T00:44:57.510066",
"last_name": "",
"resource_uri": "/api/v1/user/1/",
"username": "daniel"
}
You can do a similar fetch using the following Javascript/jQuery (though be wary of same-domain policy):
$.ajax({
url: 'http://localhost:8000/api/v1/user/1/',
type: 'GET',
accepts: 'application/json',
dataType: 'json'
})
Selecting A Subset Of Resources¶
Sometimes you may want back more than one record, but not an entire list view nor do you want to do multiple requests. Tastypie includes a “set” view, which lets you cherry-pick the objects you want. For example, if we just want the first & third Entry resources, we’d run:
curl "http://localhost:8000/api/v1/entry/set/1;3/"
Note
Quotes are needed in this case because of the semicolon delimiter between primary keys. Without the quotes, bash tries to split it into two statements. No extraordinary quoting will be necessary in your application (unless your API client is written in bash :D).
And we get back just those two objects:
{
"objects": [{
"body": "Welcome to my blog!",
"id": "1",
"pub_date": "2011-05-20T00:46:38",
"resource_uri": "/api/v1/entry/1/",
"slug": "first-post",
"title": "First Post",
"user": "/api/v1/user/1/"
},
{
"body": "I'm really excited to get started with this new blog. It's gonna be great!",
"id": "3",
"pub_date": "2011-05-20T00:47:30",
"resource_uri": "/api/v1/entry/3/",
"slug": "my-blog",
"title": "My Blog",
"user": "/api/v1/user/2/"
}]
}
Note that, like the list view, you get back a list of objects. Unlike the list view, there is NO pagination applied to these objects. You asked for them, you’re going to get them all.
Sending Data¶
Tastypie also gives you full write capabilities in the API. Since the EntryResource has the no-limits Authentication & Authorization on it, we can freely write data.
Warning
Note that this is a huge security hole as well. Don’t put unauthorized write-enabled resources on the Internet, because someone will trash your data.
This is why ReadOnlyAuthorization is the default in Tastypie & why you must override to provide more access.
The good news is that there are no new URLs to learn. The “list” & “detail” URLs we’ve been using to fetch data ALSO support the POST/PUT/DELETE HTTP methods.
Creating A New Resource (POST)¶
Let’s add a new entry. To create new data, we’ll switch from GET requests to the familiar POST request.
Note
Tastypie encourages “round-trippable” data, which means the data you can GET should be able to be POST/PUT’d back to recreate the same object.
If you’re ever in question about what you should send, do a GET on another object & see what Tastypie thinks it should look like.
To create new resources/objects, you will POST to the list endpoint of a resource. Trying to POST to a detail endpoint has a different meaning in the REST mindset (meaning to add a resource as a child of a resource of the same type).
As with all Tastypie requests, the headers we request are important. Since we’ve been using primarily JSON throughout, let’s send a new entry in JSON format:
curl --dump-header - -H "Content-Type: application/json" -X POST --data '{"body": "This will prbbly be my lst post.", "pub_date": "2011-05-22T00:46:38", "slug": "another-post", "title": "Another Post", "user": "/api/v1/user/1/"}' http://localhost:8000/api/v1/entry/
The Content-Type header here informs Tastypie that we’re sending it JSON. We send the data as a JSON-serialized body (NOT as form-data in the form of URL parameters). What we get back is the following response:
HTTP/1.0 201 CREATED
Date: Fri, 20 May 2011 06:48:36 GMT
Server: WSGIServer/0.1 Python/2.7
Content-Type: text/html; charset=utf-8
Location: http://localhost:8000/api/v1/entry/4/
You’ll also note that we get a correct HTTP status code back (201) & a Location header, which gives us the URI to our newly created resource.
Passing --dump-header - is important, because it gives you all the headers as well as the status code. When things go wrong, this will be useful information to help with debugging. For instance, if we send a request without a user:
curl --dump-header - -H "Content-Type: application/json" -X POST --data '{"body": "This will prbbly be my lst post.", "pub_date": "2011-05-22T00:46:38", "slug": "another-post", "title": "Another Post"}' http://localhost:8000/api/v1/entry/
We get back:
HTTP/1.0 400 BAD REQUEST
Date: Fri, 20 May 2011 06:53:02 GMT
Server: WSGIServer/0.1 Python/2.7
Content-Type: text/html; charset=utf-8
The 'user' field has no data and doesn't allow a default or null value.
You can do a similar POST using the following Javascript/jQuery (though be wary of same-domain policy):
# This may require the ``json2.js`` library for older browsers.
var data = JSON.stringify({
"body": "This will prbbly be my lst post.",
"pub_date": "2011-05-22T00:46:38",
"slug": "another-post",
"title": "Another Post"
});
$.ajax({
url: 'http://localhost:8000/api/v1/entry/',
type: 'POST',
contentType: 'application/json',
data: data,
dataType: 'json',
processData: false
})
Updating An Existing Resource (PUT)¶
You might have noticed that we made some typos when we submitted the POST request. We can fix this using a PUT request to the detail endpoint (modify this instance of a resource).:
curl --dump-header - -H "Content-Type: application/json" -X PUT --data '{"body": "This will probably be my last post.", "pub_date": "2011-05-22T00:46:38", "slug": "another-post", "title": "Another Post", "user": "/api/v1/user/1/"}' http://localhost:8000/api/v1/entry/4/
After fixing up the body, we get back:
HTTP/1.0 204 NO CONTENT
Date: Fri, 20 May 2011 07:13:21 GMT
Server: WSGIServer/0.1 Python/2.7
Content-Length: 0
Content-Type: text/html; charset=utf-8
We get a 204 status code, meaning our update was successful. We don’t get a Location header back because we did the PUT on a detail URL, which presumably did not change.
Note
A PUT request requires that the entire resource representation be enclosed. Missing fields may cause errors, or be filled in by default values.
Partially Updating An Existing Resource (PATCH)¶
In some cases, you may not want to send the entire resource when updating. To update just a subset of the fields, we can send a PATCH request to the detail endpoint.:
curl --dump-header - -H "Content-Type: application/json" -X PATCH --data '{"body": "This actually is my last post."}' http://localhost:8000/api/v1/entry/4/
To which we should get back:
HTTP/1.0 202 ACCEPTED
Date: Fri, 20 May 2011 07:13:21 GMT
Server: WSGIServer/0.1 Python/2.7
Content-Length: 0
Content-Type: text/html; charset=utf-8
Updating A Whole Collection Of Resources (PUT)¶
You can also, in rare circumstances, update an entire collection of objects. By sending a PUT request to the list view of a resource, you can replace the entire collection.
Warning
This deletes all of the objects first, then creates the objects afresh. This is done because determining which objects are the same is actually difficult to get correct in the general case for all people.
Send a request like:
curl --dump-header - -H "Content-Type: application/json" -X PUT --data '{"objects": [{"body": "Welcome to my blog!","id": "1","pub_date": "2011-05-20T00:46:38","resource_uri": "/api/v1/entry/1/","slug": "first-post","title": "First Post","user": "/api/v1/user/1/"},{"body": "I'm really excited to get started with this new blog. It's gonna be great!","id": "3","pub_date": "2011-05-20T00:47:30","resource_uri": "/api/v1/entry/3/","slug": "my-blog","title": "My Blog","user": "/api/v1/user/2/"}]}' http://localhost:8000/api/v1/entry/
And you’ll get back a response like:
HTTP/1.0 204 NO CONTENT
Date: Fri, 20 May 2011 07:13:21 GMT
Server: WSGIServer/0.1 Python/2.7
Content-Length: 0
Content-Type: text/html; charset=utf-8
Deleting Data¶
No CRUD setup would be complete without the ability to delete resources/objects. Deleting also requires significantly less complicated requests than POST/PUT.
Deleting A Single Resource¶
We’ve decided that we don’t like the entry we added & edited earlier. Let’s delete it (but leave the other objects alone):
curl --dump-header - -H "Content-Type: application/json" -X DELETE http://localhost:8000/api/v1/entry/4/
Once again, we get back the “Accepted” response of a 204:
HTTP/1.0 204 NO CONTENT
Date: Fri, 20 May 2011 07:28:01 GMT
Server: WSGIServer/0.1 Python/2.7
Content-Length: 0
Content-Type: text/html; charset=utf-8
If we request that resource, we get a 410 to show it’s no longer there:
curl --dump-header - http://localhost:8000/api/v1/entry/4/
HTTP/1.0 410 GONE
Date: Fri, 20 May 2011 07:29:02 GMT
Server: WSGIServer/0.1 Python/2.7
Content-Type: text/html; charset=utf-8
Additionally, if we try to run the DELETE again (using the same original command), we get the “Gone” response again:
HTTP/1.0 410 GONE
Date: Fri, 20 May 2011 07:30:00 GMT
Server: WSGIServer/0.1 Python/2.7
Content-Type: text/html; charset=utf-8
Deleting A Whole Collection Of Resources¶
Finally, it’s possible to remove an entire collection of resources. This is as destructive as it sounds. Once again, we use the DELETE method, this time on the entire list endpoint:
curl --dump-header - -H "Content-Type: application/json" -X DELETE http://localhost:8000/api/v1/entry/
As a response, we get:
HTTP/1.0 204 NO CONTENT
Date: Fri, 20 May 2011 07:32:51 GMT
Server: WSGIServer/0.1 Python/2.7
Content-Length: 0
Content-Type: text/html; charset=utf-8
Hitting the list view:
curl --dump-header - http://localhost:8000/api/v1/entry/
Gives us a 200 but no objects:
{
"meta": {
"limit": 20,
"next": null,
"offset": 0,
"previous": null,
"total_count": 0
},
"objects": []
}
Bulk Operations¶
As an optimization, it is possible to do many creations, updates, and deletions to a collection in a single request by sending a PATCH to the list endpoint.:
curl --dump-header - -H "Content-Type: application/json" -X PATCH --data '{"objects": [{"body": "Surprise! Another post!.", "pub_date": "2012-02-16T00:46:38", "slug": "yet-another-post", "title": "Yet Another Post"}], "deleted_objects": ["http://localhost:8000/api/v1/entry/4/"]}' http://localhost:8000/api/v1/entry/
We should get back:
HTTP/1.0 202 ACCEPTED
Date: Fri, 16 Feb 2012 00:46:38 GMT
Server: WSGIServer/0.1 Python/2.7
Content-Length: 0
Content-Type: text/html; charset=utf-8
The Accepted response means the server has accepted the request, but gives no details on the result. In order to see any created resources, we would need to do a get GET on the list endpoint.
For detailed information on the format of a bulk request, see patch_list.
You Did It!¶
That’s a whirlwind tour of interacting with a Tastypie API. There’s additional functionality present, such as:
- POST/PUT the other supported content-types
- More filtering/order_by/limit/offset tricks
- Using overridden URLconfs to support complex or non-PK lookups
- Authentication
But this grounds you in the basics & hopefully clarifies usage/debugging better.
Tastypie Settings¶
This is a comprehensive list of the settings Tastypie recognizes.
API_LIMIT_PER_PAGE¶
Optional
This setting controls the default number of records Tastypie will show in a list view.
This is only used when a user does not specify a limit GET parameter and the Resource subclass has not overridden the number to be shown.
An example:
API_LIMIT_PER_PAGE = 50
If you don’t want to limit the number of records by default, you can set this setting to 0:
API_LIMIT_PER_PAGE = 0
Defaults to 20.
TASTYPIE_FULL_DEBUG¶
Optional
This setting controls what the behavior is when an unhandled exception occurs.
If set to True and settings.DEBUG = True, the standard Django technical 500 is displayed.
If not set or set to False, Tastypie will return a serialized response. If settings.DEBUG is True, you’ll get the actual exception message plus a traceback. If settings.DEBUG is False, Tastypie will call mail_admins() and provide a canned error message (which you can override with TASTYPIE_CANNED_ERROR) in the response.
An example:
TASTYPIE_FULL_DEBUG = True
Defaults to False.
TASTYPIE_CANNED_ERROR¶
Optional
This setting allows you to override the canned error response when an unhandled exception is raised and settings.DEBUG is False.
An example:
TASTYPIE_CANNED_ERROR = "Oops, we broke it!"
Defaults to "Sorry, this request could not be processed. Please try again later.".
TASTYPIE_ALLOW_MISSING_SLASH¶
Optional
This setting allows your URLs to be missing the final slash. Useful for integrating with other systems.
You must also have settings.APPEND_SLASH = False so that Django does not emit HTTP 302 redirects.
An example:
TASTYPIE_ALLOW_MISSING_SLASH = True
Defaults to False.
TASTYPIE_DATETIME_FORMATTING¶
Optional
This setting allows you to globally choose what format your datetime/date/time data will be formatted in. Valid options are iso-8601, iso-8601-strict & rfc-2822.
An example:
TASTYPIE_DATETIME_FORMATTING = 'rfc-2822'
Defaults to iso-8601. iso-8601 includes microseconds if available, use iso-8601-strict to strip them.
TASTYPIE_DEFAULT_FORMATS¶
Optional
This setting allows you to globally configure the list of allowed serialization formats for your entire site.
An example:
TASTYPIE_DEFAULT_FORMATS = ['json', 'xml']
Defaults to ['json', 'xml', 'yaml', 'html', 'plist'].
TASTYPIE_ABSTRACT_APIKEY¶
Optional
This setting makes the ApiKey model an abstract base class. This may be useful in multi-database setups where many databases each have their own table for user data and ApiKeyAuthentication is not used. Without this setting, the tastypie_apikey table would have to be created on each database containing user account data (such as Django’s built-in auth_user table generated by django.contrib.auth.models.User). Valid options are True & False.
An example:
TASTYPIE_ABSTRACT_APIKEY = True
Defaults to False.
Using Tastypie With Non-ORM Data Sources¶
Much of this documentation demonstrates the use of Tastypie with Django’s ORM. You might think that Tastypie depended on the ORM, when in fact, it was purpose-built to handle non-ORM data. This documentation should help you get started providing APIs using other data sources.
Virtually all of the code that makes Tastypie actually process requests & return data is within the Resource class. ModelResource is actually a light wrapper around Resource that provides ORM-specific access. The methods that ModelResource overrides are the same ones you’ll need to override when hooking up your data source.
Approach¶
When working with Resource, many things are handled for you. All the authentication/authorization/caching/serialization/throttling bits should work as normal and Tastypie can support all the REST-style methods. Schemas & discovery views all work the same as well.
What you don’t get out of the box are the fields you’re choosing to expose & the lowest level data access methods. If you want a full read-write API, there are nine methods you need to implement. They are:
- detail_uri_kwargs
- get_object_list
- obj_get_list
- obj_get
- obj_create
- obj_update
- obj_delete_list
- obj_delete
- rollback
If read-only is all you’re exposing, you can cut that down to four methods to override.
Using Riak for MessageResource¶
As an example, we’ll take integrating with Riak (a Dynamo-like NoSQL store) since it has both a simple API and demonstrate what hooking up to a non-relational datastore looks like:
# We need a generic object to shove data in/get data from.
# Riak generally just tosses around dictionaries, so we'll lightly
# wrap that.
class RiakObject(object):
def __init__(self, initial=None):
self.__dict__['_data'] = {}
if hasattr(initial, 'items'):
self.__dict__['_data'] = initial
def __getattr__(self, name):
return self._data.get(name, None)
def __setattr__(self, name, value):
self.__dict__['_data'][name] = value
def to_dict(self):
return self._data
class MessageResource(Resource):
# Just like a Django ``Form`` or ``Model``, we're defining all the
# fields we're going to handle with the API here.
uuid = fields.CharField(attribute='uuid')
user_uuid = fields.CharField(attribute='user_uuid')
message = fields.CharField(attribute='message')
created = fields.IntegerField(attribute='created')
class Meta:
resource_name = 'riak'
object_class = RiakObject
authorization = Authorization()
# Specific to this resource, just to get the needed Riak bits.
def _client(self):
return riak.RiakClient()
def _bucket(self):
client = self._client()
# Note that we're hard-coding the bucket to use. Fine for
# example purposes, but you'll want to abstract this.
return client.bucket('messages')
# The following methods will need overriding regardless of your
# data source.
def detail_uri_kwargs(self, bundle_or_obj):
kwargs = {}
if isinstance(bundle_or_obj, Bundle):
kwargs['pk'] = bundle_or_obj.obj.uuid
else:
kwargs['pk'] = bundle_or_obj.uuid
return kwargs
def get_object_list(self, request):
query = self._client().add('messages')
query.map("function(v) { var data = JSON.parse(v.values[0].data); return [[v.key, data]]; }")
results = []
for result in query.run():
new_obj = RiakObject(initial=result[1])
new_obj.uuid = result[0]
results.append(new_obj)
return results
def obj_get_list(self, request=None, **kwargs):
# Filtering disabled for brevity...
return self.get_object_list(request)
def obj_get(self, request=None, **kwargs):
bucket = self._bucket()
message = bucket.get(kwargs['pk'])
return RiakObject(initial=message.get_data())
def obj_create(self, bundle, request=None, **kwargs):
bundle.obj = RiakObject(initial=kwargs)
bundle = self.full_hydrate(bundle)
bucket = self._bucket()
new_message = bucket.new(bundle.obj.uuid, data=bundle.obj.to_dict())
new_message.store()
return bundle
def obj_update(self, bundle, request=None, **kwargs):
return self.obj_create(bundle, request, **kwargs)
def obj_delete_list(self, request=None, **kwargs):
bucket = self._bucket()
for key in bucket.get_keys():
obj = bucket.get(key)
obj.delete()
def obj_delete(self, request=None, **kwargs):
bucket = self._bucket()
obj = bucket.get(kwargs['pk'])
obj.delete()
def rollback(self, bundles):
pass
This represents a full, working, Riak-powered API endpoint. All REST-style actions (GET/POST/PUT/DELETE) all work correctly. The only shortcut taken in this example was skipping filter-abilty, as adding in the MapReduce bits would have decreased readability.
All said and done, just nine methods needed overriding, eight of which were highly specific to how data access is done.
Tools¶
Here are some tools that might help in interacting with the API that Tastypie provides:
Browser¶
JSONView¶
- Firefox - https://addons.mozilla.org/en-US/firefox/addon/jsonview/
- Chrome - https://chrome.google.com/webstore/detail/chklaanhfefbnpoihckbnefhakgolnmc
A plugin (actually two different ones that closely mirror each other) that nicely reformats JSON data in the browser.
Extensions¶
Tastypie-msgpack¶
https://github.com/stephenmcd/tastypie-msgpack
Adds MsgPack support to Tastypie’s serializer.
Python¶
Slumber¶
Slumber is a small Python library that makes it easy to access & work with APIs. It works for many others, but works especially well with Tastypie.
Hammock¶
https://github.com/kadirpekel/hammock
Hammock is a fun module lets you deal with rest APIs by converting them into dead simple programmatic APIs. It uses popular requests module in backyard to provide full-fledged rest experience.
Here is what it looks like:
>>> import hammock
>>> api = hammock.Hammock('http://localhost:8000')
>>> api.users('foo').posts('bar').comments.GET()
<Response [200]>
drest¶
drest is another small Python library. It focuses on extensibility & can also work with many different API, with an emphasis on Tastypie.
json.tool¶
Included with Python, this tool makes reformatting JSON easy. For example:
$ curl http://localhost:8000/api/v1/note/ | python -m json.tool
Will return nicely reformatted data like:
{
"meta": {
"total_count": 1
},
"objects": [
{
"content": "Hello world!",
"user": "/api/v1/user/1/"
}
]
}
Javascript¶
backbone-tastypie¶
https://github.com/PaulUithol/backbone-tastypie
A small layer that makes Backbone & Tastypie plan nicely together.
backbone-relational¶
https://github.com/PaulUithol/Backbone-relational/
Allows Backbone to work with relational data, like the kind of data Tastypie provides.
Testing¶
Having integrated unit tests that cover your API’s behavior is important, as it helps provide verification that your API code is still valid & working correctly with the rest of your application.
Tastypie provides some basic facilities that build on top of Django’s testing support, in the form of a specialized TestApiClient & ResourceTestCase.
The ResourceTestCase builds on top of Django’s TestCase. It provides quite a few extra assertion methods that are specific to APIs. Under the hood, it uses the TestApiClient to perform requests properly.
The TestApiClient builds on & exposes an interface similar to that of Django’s Client. However, under the hood, it hands all the setup needed to construct a proper request.
Example Usage¶
The typical use case will primarily consist of subclassing the ResourceTestCase class & using the built-in assertions to ensure your API is behaving correctly. For the purposes of this example, we’ll assume the resource in question looks like:
from tastypie.authentication import BasicAuthentication
from tastypie.resources import ModelResource
from entries.models import Entry
class EntryResource(ModelResource):
class Meta:
queryset = Entry.objects.all()
authentication = BasicAuthentication()
An example usage might look like:
import datetime
from django.contrib.auth.models import User
from tastypie.test import ResourceTestCase
from entries.models import Entry
class EntryResourceTest(ResourceTestCase):
# Use ``fixtures`` & ``urls`` as normal. See Django's ``TestCase``
# documentation for the gory details.
fixtures = ['test_entries.json']
def setUp(self):
super(EntryResourceTest, self).setUp()
# Create a user.
self.username = 'daniel'
self.password = 'pass'
self.user = User.objects.create_user(self.username, 'daniel@example.com', self.password)
# Fetch the ``Entry`` object we'll use in testing.
# Note that we aren't using PKs because they can change depending
# on what other tests are running.
self.entry_1 = Entry.objects.get(slug='first-post')
# We also build a detail URI, since we will be using it all over.
# DRY, baby. DRY.
self.detail_url = '/api/v1/entry/{0}/'.format(self.entry_1.pk)
# The data we'll send on POST requests. Again, because we'll use it
# frequently (enough).
self.post_data = {
'user': '/api/v1/user/{0}/'.format(self.user.pk),
'title': 'Second Post!',
'slug': 'second-post',
'created': '2012-05-01T22:05:12'
}
def get_credentials(self):
return self.create_basic(username=self.username, password=self.password)
def test_get_list_unauthorzied(self):
self.assertHttpUnauthorized(self.api_client.get('/api/v1/entries/', format='json'))
def test_get_list_json(self):
resp = self.api_client.get('/api/v1/entries/', format='json', authentication=self.get_credentials())
self.assertValidJSONResponse(resp)
# Scope out the data for correctness.
self.assertEqual(len(self.deserialize(resp)['objects']), 12)
# Here, we're checking an entire structure for the expected data.
self.assertEqual(self.deserialize(resp)['objects'][0], {
'pk': str(self.entry_1.pk),
'user': '/api/v1/user/{0}/'.format(self.user.pk),
'title': 'First post',
'slug': 'first-post',
'created': '2012-05-01T19:13:42',
'resource_uri': '/api/v1/entry/{0}/'.format(self.entry_1.pk)
})
def test_get_list_xml(self):
self.assertValidXMLResponse(self.api_client.get('/api/v1/entries/', format='xml', authentication=self.get_credentials()))
def test_get_detail_unauthenticated(self):
self.assertHttpUnauthorized(self.api_client.get(self.detail_url, format='json'))
def test_get_detail_json(self):
resp = self.api_client.get(self.detail_url, format='json', authentication=self.get_credentials())
self.assertValidJSONResponse(resp)
# We use ``assertKeys`` here to just verify the keys, not all the data.
self.assertKeys(self.deserialize(resp), ['created', 'slug', 'title', 'user'])
self.assertEqual(self.deserialize(resp)['name'], 'First post')
def test_get_detail_xml(self):
self.assertValidXMLResponse(self.api_client.get(self.detail_url, format='xml', authentication=self.get_credentials()))
def test_post_list_unauthenticated(self):
self.assertHttpUnauthorized(self.api_client.post('/api/v1/entries/', format='json', data=self.post_data))
def test_post_list(self):
# Check how many are there first.
self.assertEqual(Entry.objects.count(), 5)
self.assertHttpCreated(self.api_client.post('/api/v1/entries/', format='json', data=self.post_data, authentication=self.get_credentials()))
# Verify a new one has been added.
self.assertEqual(Entry.objects.count(), 6)
def test_put_detail_unauthenticated(self):
self.assertHttpUnauthorized(self.api_client.put(self.detail_url, format='json', data={}))
def test_put_detail(self):
# Grab the current data & modify it slightly.
original_data = self.deserialize(self.api_client.get(self.detail_url, format='json', authentication=self.get_credentials()))
new_data = original_data.copy()
new_data['title'] = 'Updated: First Post'
new_data['created'] = '2012-05-01T20:06:12'
self.assertEqual(Entry.objects.count(), 5)
self.assertHttpAccepted(self.api_client.put(self.detail_url, format='json', data=new_data, authentication=self.get_credentials()))
# Make sure the count hasn't changed & we did an update.
self.assertEqual(Entry.objects.count(), 5)
# Check for updated data.
self.assertEqual(Entry.objects.get(pk=25).title, 'Updated: First Post')
self.assertEqual(Entry.objects.get(pk=25).slug, 'first-post')
self.assertEqual(Entry.objects.get(pk=25).created, datetime.datetime(2012, 3, 1, 13, 6, 12))
def test_delete_detail_unauthenticated(self):
self.assertHttpUnauthorized(self.api_client.delete(self.detail_url, format='json'))
def test_delete_detail(self):
self.assertEqual(Entry.objects.count(), 5)
self.assertHttpAccepted(self.api_client.delete(self.detail_url, format='json', authentication=self.get_credentials()))
self.assertEqual(Entry.objects.count(), 4)
Note that this example doesn’t cover other cases, such as filtering, PUT to a list endpoint, DELETE to a list endpoint, PATCH support, etc.
ResourceTestCase API Reference¶
The ResourceTestCase exposes the following methods for use. Most are enhanced assertions or provide API-specific behaviors.
get_credentials¶
- ResourceTestCase.get_credentials(self)¶
A convenience method for the user as a way to shorten up the often repetitious calls to create the same authentication.
Raises NotImplementedError by default.
Usage:
class MyResourceTestCase(ResourceTestCase):
def get_credentials(self):
return self.create_basic('daniel', 'pass')
# Then the usual tests...
create_basic¶
- ResourceTestCase.create_basic(self, username, password)¶
Creates & returns the HTTP Authorization header for use with BASIC Auth.
create_apikey¶
- ResourceTestCase.create_apikey(self, username, api_key)¶
Creates & returns the HTTP Authorization header for use with ApiKeyAuthentication.
create_digest¶
- ResourceTestCase.create_digest(self, username, api_key, method, uri)¶
Creates & returns the HTTP Authorization header for use with Digest Auth.
create_oauth¶
- ResourceTestCase.create_oauth(self, user)¶
Creates & returns the HTTP Authorization header for use with Oauth.
assertHttpOK¶
- ResourceTestCase.assertHttpOK(self, resp)¶
Ensures the response is returning a HTTP 200.
assertHttpCreated¶
- ResourceTestCase.assertHttpCreated(self, resp)¶
Ensures the response is returning a HTTP 201.
assertHttpAccepted¶
- ResourceTestCase.assertHttpAccepted(self, resp)¶
Ensures the response is returning either a HTTP 202 or a HTTP 204.
assertHttpMultipleChoices¶
- ResourceTestCase.assertHttpMultipleChoices(self, resp)¶
Ensures the response is returning a HTTP 300.
assertHttpSeeOther¶
- ResourceTestCase.assertHttpSeeOther(self, resp)¶
Ensures the response is returning a HTTP 303.
assertHttpNotModified¶
- ResourceTestCase.assertHttpNotModified(self, resp)¶
Ensures the response is returning a HTTP 304.
assertHttpBadRequest¶
- ResourceTestCase.assertHttpBadRequest(self, resp)¶
Ensures the response is returning a HTTP 400.
assertHttpForbidden¶
- ResourceTestCase.assertHttpForbidden(self, resp)¶
Ensures the response is returning a HTTP 403.
assertHttpNotFound¶
- ResourceTestCase.assertHttpNotFound(self, resp)¶
Ensures the response is returning a HTTP 404.
assertHttpMethodNotAllowed¶
- ResourceTestCase.assertHttpMethodNotAllowed(self, resp)¶
Ensures the response is returning a HTTP 405.
assertHttpConflict¶
- ResourceTestCase.assertHttpConflict(self, resp)¶
Ensures the response is returning a HTTP 409.
assertHttpGone¶
- ResourceTestCase.assertHttpGone(self, resp)¶
Ensures the response is returning a HTTP 410.
assertHttpTooManyRequests¶
- ResourceTestCase.assertHttpTooManyRequests(self, resp)¶
Ensures the response is returning a HTTP 429.
assertHttpApplicationError¶
- ResourceTestCase.assertHttpApplicationError(self, resp)¶
Ensures the response is returning a HTTP 500.
assertHttpNotImplemented¶
- ResourceTestCase.assertHttpNotImplemented(self, resp)¶
Ensures the response is returning a HTTP 501.
assertValidJSON¶
- ResourceTestCase.assertValidJSON(self, data)¶
Given the provided data as a string, ensures that it is valid JSON & can be loaded properly.
assertValidXML¶
- ResourceTestCase.assertValidXML(self, data)¶
Given the provided data as a string, ensures that it is valid XML & can be loaded properly.
assertValidYAML¶
- ResourceTestCase.assertValidYAML(self, data)¶
Given the provided data as a string, ensures that it is valid YAML & can be loaded properly.
assertValidPlist¶
- ResourceTestCase.assertValidPlist(self, data)¶
Given the provided data as a string, ensures that it is valid binary plist & can be loaded properly.
assertValidJSONResponse¶
- ResourceTestCase.assertValidJSONResponse(self, resp)¶
Given a HttpResponse coming back from using the client, assert that you get back:
- An HTTP 200
- The correct content-type (application/json)
- The content is valid JSON
assertValidXMLResponse¶
- ResourceTestCase.assertValidXMLResponse(self, resp)¶
Given a HttpResponse coming back from using the client, assert that you get back:
- An HTTP 200
- The correct content-type (application/xml)
- The content is valid XML
assertValidYAMLResponse¶
- ResourceTestCase.assertValidYAMLResponse(self, resp)¶
Given a HttpResponse coming back from using the client, assert that you get back:
- An HTTP 200
- The correct content-type (text/yaml)
- The content is valid YAML
assertValidPlistResponse¶
- ResourceTestCase.assertValidPlistResponse(self, resp)¶
Given a HttpResponse coming back from using the client, assert that you get back:
- An HTTP 200
- The correct content-type (application/x-plist)
- The content is valid binary plist data
deserialize¶
- ResourceTestCase.deserialize(self, resp)¶
Given a HttpResponse coming back from using the client, this method checks the Content-Type header & attempts to deserialize the data based on that.
It returns a Python datastructure (typically a dict) of the serialized data.
serialize¶
- ResourceTestCase.serialize(self, data, format='application/json')¶
Given a Python datastructure (typically a dict) & a desired content-type, this method will return a serialized string of that data.
assertKeys¶
- ResourceTestCase.assertKeys(self, data, expected)¶
This method ensures that the keys of the data match up to the keys of expected.
It covers the (extremely) common case where you want to make sure the keys of a response match up to what is expected. This is typically less fragile than testing the full structure, which can be prone to data changes.
TestApiClient API Reference¶
The TestApiClient simulates a HTTP client making calls to the API. It’s important to note that it uses Django’s testing infrastructure, so it’s not making actual calls against a webserver.
__init__¶
- TestApiClient.__init__(self, serializer=None)¶
Sets up a fresh TestApiClient instance.
If you are employing a custom serializer, you can pass the class to the serializer= kwarg.
get_content_type¶
- TestApiClient.get_content_type(self, short_format)¶
Given a short name (such as json or xml), returns the full content-type for it (application/json or application/xml in this case).
get¶
- TestApiClient.get(self, uri, format='json', data=None, authentication=None, **kwargs)¶
Performs a simulated GET request to the provided URI.
Optionally accepts a data kwarg, which in the case of GET, lets you send along GET parameters. This is useful when testing filtering or other things that read off the GET params. Example:
from tastypie.test import TestApiClient
client = TestApiClient()
response = client.get('/api/v1/entry/1/', data={'format': 'json', 'title__startswith': 'a', 'limit': 20, 'offset': 60})
Optionally accepts an authentication kwarg, which should be an HTTP header with the correct authentication data already setup.
All other **kwargs passed in get passed through to the Django TestClient. See https://docs.djangoproject.com/en/dev/topics/testing/#module-django.test.client for details.
post¶
- TestApiClient.post(self, uri, format='json', data=None, authentication=None, **kwargs)¶
Performs a simulated POST request to the provided URI.
Optionally accepts a data kwarg. Unlike GET, in POST the data gets serialized & sent as the body instead of becoming part of the URI. Example:
from tastypie.test import TestApiClient
client = TestApiClient()
response = client.post('/api/v1/entry/', data={
'created': '2012-05-01T20:02:36',
'slug': 'another-post',
'title': 'Another Post',
'user': '/api/v1/user/1/',
})
Optionally accepts an authentication kwarg, which should be an HTTP header with the correct authentication data already setup.
All other **kwargs passed in get passed through to the Django TestClient. See https://docs.djangoproject.com/en/dev/topics/testing/#module-django.test.client for details.
put¶
- TestApiClient.put(self, uri, format='json', data=None, authentication=None, **kwargs)¶
Performs a simulated PUT request to the provided URI.
Optionally accepts a data kwarg. Unlike GET, in PUT the data gets serialized & sent as the body instead of becoming part of the URI. Example:
from tastypie.test import TestApiClient
client = TestApiClient()
response = client.put('/api/v1/entry/1/', data={
'created': '2012-05-01T20:02:36',
'slug': 'another-post',
'title': 'Another Post',
'user': '/api/v1/user/1/',
})
Optionally accepts an authentication kwarg, which should be an HTTP header with the correct authentication data already setup.
All other **kwargs passed in get passed through to the Django TestClient. See https://docs.djangoproject.com/en/dev/topics/testing/#module-django.test.client for details.
patch¶
- TestApiClient.patch(self, uri, format='json', data=None, authentication=None, **kwargs)¶
Performs a simulated PATCH request to the provided URI.
Optionally accepts a data kwarg. Unlike GET, in PATCH the data gets serialized & sent as the body instead of becoming part of the URI. Example:
from tastypie.test import TestApiClient
client = TestApiClient()
response = client.patch('/api/v1/entry/1/', data={
'created': '2012-05-01T20:02:36',
'slug': 'another-post',
'title': 'Another Post',
'user': '/api/v1/user/1/',
})
Optionally accepts an authentication kwarg, which should be an HTTP header with the correct authentication data already setup.
All other **kwargs passed in get passed through to the Django TestClient. See https://docs.djangoproject.com/en/dev/topics/testing/#module-django.test.client for details.
delete¶
- TestApiClient.delete(self, uri, format='json', data=None, authentication=None, **kwargs)¶
Performs a simulated DELETE request to the provided URI.
Optionally accepts a data kwarg, which in the case of DELETE, lets you send along DELETE parameters. This is useful when testing filtering or other things that read off the DELETE params. Example:
from tastypie.test import TestApiClient
client = TestApiClient()
response = client.delete('/api/v1/entry/1/', data={'format': 'json'})
Optionally accepts an authentication kwarg, which should be an HTTP header with the correct authentication data already setup.
All other **kwargs passed in get passed through to the Django TestClient. See https://docs.djangoproject.com/en/dev/topics/testing/#module-django.test.client for details.
Compatibility Notes¶
Tastypie does its best to be a good third-party app, trying to interoperate with the widest range of Django environments it can. However, there are times where certain things aren’t possible. We’ll do our best to document them here.
ApiKey Database Index¶
When the ApiKey model was added to Tastypie, an index was lacking on the key field. This was the case until the v0.9.12 release. The model was updated & a migration was added (0002_add_apikey_index.py). However, due to the way MySQL works & the way Django generates index names, this migration would fail miserably on many MySQL installs.
If you are using MySQL, South & the ApiKey authentication class, you should manually add an index for the the ApiKey.key field. Something to the effect of:
BEGIN; -- LOLMySQL
CREATE INDEX tastypie_apikey_key_index ON tastypie_apikey (`key`);
COMMIT;
Resources¶
In terms of a REST-style architecture, a “resource” is a collection of similar data. This data could be a table of a database, a collection of other resources or a similar form of data storage. In Tastypie, these resources are generally intermediaries between the end user & objects, usually Django models. As such, Resource (and its model-specific twin ModelResource) form the heart of Tastypie’s functionality.
Quick Start¶
A sample resource definition might look something like:
from django.contrib.auth.models import User
from tastypie import fields
from tastypie.authorization import DjangoAuthorization
from tastypie.resources import ModelResource, ALL, ALL_WITH_RELATIONS
from myapp.models import Entry
class UserResource(ModelResource):
class Meta:
queryset = User.objects.all()
resource_name = 'auth/user'
excludes = ['email', 'password', 'is_superuser']
class EntryResource(ModelResource):
user = fields.ForeignKey(UserResource, 'user')
class Meta:
queryset = Entry.objects.all()
list_allowed_methods = ['get', 'post']
detail_allowed_methods = ['get', 'post', 'put', 'delete']
resource_name = 'myapp/entry'
authorization = DjangoAuthorization()
filtering = {
'slug': ALL,
'user': ALL_WITH_RELATIONS,
'created': ['exact', 'range', 'gt', 'gte', 'lt', 'lte'],
}
Why Class-Based?¶
Using class-based resources make it easier to extend/modify the code to meet your needs. APIs are rarely a one-size-fits-all problem space, so Tastypie tries to get the fundamentals right and provide you with enough hooks to customize things to work your way.
As is standard, this raises potential problems for thread-safety. Tastypie has been designed to minimize the possibility of data “leaking” between threads. This does however sometimes introduce some small complexities & you should be careful not to store state on the instances if you’re going to be using the code in a threaded environment.
Why Resource vs. ModelResource?¶
Make no mistake that Django models are far and away the most popular source of data. However, in practice, there are many times where the ORM isn’t the data source. Hooking up things like a NoSQL store (see Using Tastypie With Non-ORM Data Sources), a search solution like Haystack or even managed filesystem data are all good use cases for Resource knowing nothing about the ORM.
Flow Through The Request/Response Cycle¶
Tastypie can be thought of as a set of class-based views that provide the API functionality. As such, many part of the request/response cycle are standard Django behaviors. For instance, all routing/middleware/response-handling aspects are the same as a typical Django app. Where it differs is in the view itself.
As an example, we’ll walk through what a GET request to a list endpoint (say /api/v1/user/?format=json) looks like:
The Resource.urls are checked by Django’s url resolvers.
On a match for the list view, Resource.wrap_view('dispatch_list') is called. wrap_view provides basic error handling & allows for returning serialized errors.
Because dispatch_list was passed to wrap_view, Resource.dispatch_list is called next. This is a thin wrapper around Resource.dispatch.
dispatch does a bunch of heavy lifting. It ensures:
- the requested HTTP method is in allowed_methods (method_check),
- the class has a method that can handle the request (get_list),
- the user is authenticated (is_authenticated),
- the user is authorized (is_authorized),
- & the user has not exceeded their throttle (throttle_check).
At this point, dispatch actually calls the requested method (get_list).
get_list does the actual work of the API. It does:
- A fetch of the available objects via Resource.obj_get_list. In the case of ModelResource, this builds the ORM filters to apply (ModelResource.build_filters). It then gets the QuerySet via ModelResource.get_object_list (which performs Resource.apply_authorization_limits to possibly limit the set the user can work with) and applies the built filters to it.
- It then sorts the objects based on user input (ModelResource.apply_sorting).
- Then it paginates the results using the supplied Paginator & pulls out the data to be serialized.
- The objects in the page have full_dehydrate applied to each of them, causing Tastypie to translate the raw object data into the fields the endpoint supports.
- Finally, it calls Resource.create_response.
create_response is a shortcut method that:
- Determines the desired response format (Resource.determine_format),
- Serializes the data given to it in the proper format,
- And returns a Django HttpResponse (200 OK) with the serialized data.
We bubble back up the call stack to dispatch. The last thing dispatch does is potentially store that a request occurred for future throttling (Resource.log_throttled_access) then either returns the HttpResponse or wraps whatever data came back in a response (so Django doesn’t freak out).
Processing on other endpoints or using the other HTTP methods results in a similar cycle, usually differing only in what “actual work” method gets called (which follows the format of “<http_method>_<list_or_detail>”). In the case of POST/PUT, the hydrate cycle additionally takes place and is used to take the user data & convert it to raw data for storage.
Why Resource URIs?¶
Resource URIs play a heavy role in how Tastypie delivers data. This can seem very different from other solutions which simply inline related data. Though Tastypie can inline data like that (using full=True on the field with the relation), the default is to provide URIs.
URIs are useful because it results in smaller payloads, letting you fetch only the data that is important to you. You can imagine an instance where an object has thousands of related items that you may not be interested in.
URIs are also very cache-able, because the data at each endpoint is less likely to frequently change.
And URIs encourage proper use of each endpoint to display the data that endpoint covers.
Ideology aside, you should use whatever suits you. If you prefer fewer requests & fewer endpoints, use of full=True is available, but be aware of the consequences of each approach.
Accessing The Current Request¶
Being able to change behavior based on the current request is a very commmon need. Virtually anywhere within Resource/ModelResource, if a bundle is available, you can access it using bundle.request. This is useful for altering querysets, ensuring headers are present, etc.
Most methods you may need to override/extend should get a bundle passed to them.
If you’re using the Resource/ModelResource directly, with no request available, an empty Request will be supplied instead. If this is a common pattern/usage in your code, you’ll want to accommodate for data that potentially isn’t there.
Advanced Data Preparation¶
Not all data can be easily pull off an object/model attribute. And sometimes, you (or the client) may need to send data that doesn’t neatly fit back into the data model on the server side. For this, Tastypie has the “dehydrate/hydrate” cycle.
The Dehydrate Cycle¶
Tastypie uses a “dehydrate” cycle to prepare data for serialization, which is to say that it takes the raw, potentially complicated data model & turns it into a (generally simpler) processed data structure for client consumption. This usually means taking a complex data object & turning it into a dictionary of simple data types.
Broadly speaking, this takes the bundle.obj instance & builds bundle.data, which is what is actually serialized.
The cycle looks like:
- Put the data model into a Bundle instance, which is then passed through the various methods.
- Run through all fields on the Resource, letting each field perform its own dehydrate method on the bundle.
- While processing each field, look for a dehydrate_<fieldname> method on the Resource. If it’s present, call it with the bundle.
- Finally, after all fields are processed, if the dehydrate method is present on the Resource, it is called & given the entire bundle.
The goal of this cycle is to populate the bundle.data dictionary with data suitable for serialization. With the exception of the alter_* methods (as hooks to manipulate the overall structure), this cycle controls what is actually handed off to be serialized & sent to the client.
Per-field dehydrate¶
Each field (even custom ApiField subclasses) has its own dehydrate method. If it knows how to access data (say, given the attribute kwarg), it will attempt to populate values itself.
The return value is put in the bundle.data dictionary (by the Resource) with the fieldname as the key.
dehydrate_FOO¶
Since not all data may be ready for consumption based on just attribute access (or may require an advanced lookup/calculation), this hook enables you to fill in data or massage whatever the field generated.
Note
The FOO here is not literal. Instead, it is a placeholder that should be replaced with the fieldname in question.
Defining these methods is especially common when denormalizing related data, providing statistics or filling in unrelated data.
A simple example:
class MyResource(ModelResource):
# The ``title`` field is already added to the class by ``ModelResource``
# and populated off ``Note.title``. But we want allcaps titles...
class Meta:
queryset = Note.objects.all()
def dehydrate_title(self, bundle):
return bundle.data['title'].upper()
A complex example:
class MyResource(ModelResource):
# As is, this is just an empty field. Without the ``dehydrate_rating``
# method, no data would be populated for it.
rating = fields.FloatField(readonly=True)
class Meta:
queryset = Note.objects.all()
def dehydrate_rating(self, bundle):
total_score = 0.0
# Make sure we don't have to worry about "divide by zero" errors.
if not bundle.obj.rating_set.count():
return rating
# We'll run over all the ``Rating`` objects & calculate an average.
for rating in bundle.obj.rating_set.all():
total_score += rating.rating
return total_score / bundle.obj.rating_set.count()
The return value is updated in the bundle.data. You should avoid altering bundle.data here if you can help it.
dehydrate¶
The dehydrate method takes a now fully-populated bundle.data & make any last alterations to it. This is useful for when a piece of data might depend on more than one field, if you want to shove in extra data that isn’t worth having its own field or if you want to dynamically remove things from the data to be returned.
A simple example:
class MyResource(ModelResource):
class Meta:
queryset = Note.objects.all()
def dehydrate(self, bundle):
# Include the request IP in the bundle.
bundle.data['request_ip'] = bundle.request.META.get('REMOTE_ADDR')
return bundle
A complex example:
class MyResource(ModelResource):
class Meta:
queryset = User.objects.all()
excludes = ['email', 'password', 'is_staff', 'is_superuser']
def dehydrate(self, bundle):
# If they're requesting their own record, add in their email address.
if bundle.request.user.pk == bundle.obj.pk:
# Note that there isn't an ``email`` field on the ``Resource``.
# By this time, it doesn't matter, as the built data will no
# longer be checked against the fields on the ``Resource``.
bundle.data['email'] = bundle.obj.email
return bundle
This method should return a bundle, whether it modifies the existing one or creates a whole new one. You can even remove any/all data from the bundle.data if you wish.
The Hydrate Cycle¶
Tastypie uses a “hydrate” cycle to take serializated data from the client and turn it into something the data model can use. This is the reverse process from the dehydrate cycle. In fact, by default, Tastypie’s serialized data should be “round-trip-able”, meaning the data that comes out should be able to be fed back in & result in the same original data model. This usually means taking a dictionary of simple data types & turning it into a complex data object.
Broadly speaking, this takes the recently-deserialized bundle.data dictionary & builds bundle.obj (but does NOT save it).
The cycle looks like:
- Put the data from the client into a Bundle instance, which is then passed through the various methods.
- If the hydrate method is present on the Resource, it is called & given the entire bundle.
- Then run through all fields on the Resource, look for a hydrate_<fieldname> method on the Resource. If it’s present, call it with the bundle.
- Finally after all other processing is done, while processing each field, let each field perform its own hydrate method on the bundle.
The goal of this cycle is to populate the bundle.obj data model with data suitable for saving/persistence. Again, with the exception of the alter_* methods (as hooks to manipulate the overall structure), this cycle controls how the data from the client is interpreted & placed on the data model.
hydrate¶
The hydrate method allows you to make initial changes to the bundle.obj. This includes things like prepopulating fields you don’t expose over the API, recalculating related data or mangling data.
Example:
class MyResource(ModelResource):
# The ``title`` field is already added to the class by ``ModelResource``
# and populated off ``Note.title``. We'll use that title to build a
# ``Note.slug`` as well.
class Meta:
queryset = Note.objects.all()
def hydrate(self, bundle):
# Don't change existing slugs.
# In reality, this would be better implemented at the ``Note.save``
# level, but is for demonstration.
if not bundle.obj.pk:
bundle.obj.slug = slugify(bundle.data['title'])
return bundle
This method should return a bundle, whether it modifies the existing one or creates a whole new one. You can even remove any/all data from the bundle.obj if you wish.
hydrate_FOO¶
Data from the client may not map directly onto the data model or might need augmentation. This hook lets you take that data & convert it.
Note
The FOO here is not literal. Instead, it is a placeholder that should be replaced with the fieldname in question.
A simple example:
class MyResource(ModelResource):
# The ``title`` field is already added to the class by ``ModelResource``
# and populated off ``Note.title``. But we want lowercase titles...
class Meta:
queryset = Note.objects.all()
def hydrate_title(self, bundle):
bundle.data['title'] = bundle.data['title'].lower()
return bundle
The return value is the bundle.
Per-field hydrate¶
Each field (even custom ApiField subclasses) has its own hydrate method. If it knows how to access data (say, given the attribute kwarg), it will attempt to take data from the bundle.data & assign it on the data model.
The return value is put in the bundle.obj attribute for that fieldname.
Reverse “Relationships”¶
Unlike Django’s ORM, Tastypie does not automatically create reverse relations. This is because there is substantial technical complexity involved, as well as perhaps unintentionally exposing related data in an incorrect way to the end user of the API.
However, it is still possible to create reverse relations. Instead of handing the ToOneField or ToManyField a class, pass them a string that represents the full path to the desired class. Implementing a reverse relationship looks like so:
# myapp/api/resources.py
from tastypie import fields
from tastypie.resources import ModelResource
from myapp.models import Note, Comment
class NoteResource(ModelResource):
comments = fields.ToManyField('myapp.api.resources.CommentResource', 'comments')
class Meta:
queryset = Note.objects.all()
class CommentResource(ModelResource):
note = fields.ToOneField(NoteResource, 'notes')
class Meta:
queryset = Comment.objects.all()
Warning
Unlike Django, you can’t use just the class name (i.e. 'CommentResource'), even if it’s in the same module. Tastypie (intentionally) lacks a construct like the AppCache which makes that sort of thing work in Django. Sorry.
Tastypie also supports self-referential relations. If you assume we added the appropriate self-referential ForeignKey to the Note model, implementing a similar relation in Tastypie would look like:
# myapp/api/resources.py
from tastypie import fields
from tastypie.resources import ModelResource
from myapp.models import Note
class NoteResource(ModelResource):
sub_notes = fields.ToManyField('self', 'notes')
class Meta:
queryset = Note.objects.all()
Resource Options (AKA Meta)¶
The inner Meta class allows for class-level configuration of how the Resource should behave. The following options are available:
serializer¶
Controls which serializer class the Resource should use. Default is tastypie.serializers.Serializer().
authentication¶
Controls which authentication class the Resource should use. Default is tastypie.authentication.Authentication().
authorization¶
Controls which authorization class the Resource should use. Default is tastypie.authorization.ReadOnlyAuthorization().
validation¶
Controls which validation class the Resource should use. Default is tastypie.validation.Validation().
paginator_class¶
Controls which paginator class the Resource should use. Default is tastypie.paginator.Paginator.
Note
This is different than the other options in that you supply a class rather than an instance. This is done because the Paginator has some per-request initialization options.
cache¶
Controls which cache class the Resource should use. Default is tastypie.cache.NoCache().
throttle¶
Controls which throttle class the Resource should use. Default is tastypie.throttle.BaseThrottle().
allowed_methods¶
Controls what list & detail REST methods the Resource should respond to. Default is None, which means delegate to the more specific list_allowed_methods & detail_allowed_methods options.
You may specify a list like ['get', 'post', 'put', 'delete', 'patch'] as a shortcut to prevent having to specify the other options.
list_allowed_methods¶
Controls what list REST methods the Resource should respond to. Default is ['get', 'post', 'put', 'delete', 'patch'].
detail_allowed_methods¶
Controls what detail REST methods the Resource should respond to. Default is ['get', 'post', 'put', 'delete', 'patch'].
limit¶
Controls how many results the Resource will show at a time. Default is either the API_LIMIT_PER_PAGE setting (if provided) or 20 if not specified.
max_limit¶
Controls the maximum number of results the Resource will show at a time. If the user-specified limit is higher than this, it will be capped to this limit. Set to 0 or None to allow unlimited results.
api_name¶
An override for the Resource to use when generating resource URLs. Default is None.
resource_name¶
An override for the Resource to use when generating resource URLs. Default is None.
If not provided, the Resource or ModelResource will attempt to name itself. This means a lowercase version of the classname preceding the word Resource if present (i.e. SampleContentResource would become samplecontent).
default_format¶
Specifies the default serialization format the Resource should use if one is not requested (usually by the Accept header or format GET parameter). Default is application/json.
filtering¶
Provides a list of fields that the Resource will accept client filtering on. Default is {}.
Keys should be the fieldnames as strings while values should be a list of accepted filter types.
ordering¶
Specifies the what fields the Resource should should allow ordering on. Default is [].
Values should be the fieldnames as strings. When provided to the Resource by the order_by GET parameter, you can specify either the fieldname (ascending order) or -fieldname (descending order).
object_class¶
Provides the Resource with the object that serves as the data source. Default is None.
In the case of ModelResource, this is automatically populated by the queryset option and is the model class.
queryset¶
Provides the Resource with the set of Django models to respond with. Default is None.
Unused by Resource but present for consistency.
Warning
If you place any callables in this, they’ll only be evaluated once (when the Meta class is instantiated). This especially affects things that are date/time related. Please see the :ref:cookbook for a way around this.
fields¶
Controls what introspected fields the Resource should include. A whitelist of fields. Default is [].
excludes¶
Controls what introspected fields the Resource should NOT include. A blacklist of fields. Default is [].
include_resource_uri¶
Specifies if the Resource should include an extra field that displays the detail URL (within the api) for that resource. Default is True.
include_absolute_url¶
Specifies if the Resource should include an extra field that displays the get_absolute_url for that object (on the site proper). Default is False.
always_return_data¶
Specifies all HTTP methods (except DELETE) should return a serialized form of the data. Default is False.
If False, HttpNoContent (204) is returned on PUT with an empty body & a Location header of where to request the full resource.
If True, HttpResponse (200) is returned on POST/PUT with a body containing all the data in a serialized form.
collection_name¶
Specifies the collection of objects returned in the GET list will be named. Default is objects.
detail_uri_name¶
Specifies the name for the regex group that matches on detail views. Defaults to pk.
Basic Filtering¶
ModelResource provides a basic Django ORM filter interface. Simply list the resource fields which you’d like to filter on and the allowed expression in a filtering property of your resource’s Meta class:
from tastypie.constants import ALL, ALL_WITH_RELATIONS
class MyResource(ModelResource):
class Meta:
filtering = {
"slug": ('exact', 'startswith',),
"title": ALL,
}
Valid filtering values are: Django ORM filters (e.g. startswith, exact, lte, etc. or the ALL or ALL_WITH_RELATIONS constants defined in tastypie.constants.
These filters will be extracted from URL query strings using the same double-underscore syntax as the Django ORM:
/api/v1/myresource/?slug=myslug
/api/v1/myresource/?slug__startswith=test
Advanced Filtering¶
If you need to filter things other than ORM resources or wish to apply additional constraints (e.g. text filtering using django-haystack <http://haystacksearch.org> rather than simple database queries) your Resource may define a custom build_filters() method which allows you to filter the queryset before processing a request:
from haystack.query import SearchQuerySet
class MyResource(Resource):
def build_filters(self, filters=None):
if filters is None:
filters = {}
orm_filters = super(MyResource, self).build_filters(filters)
if "q" in filters:
sqs = SearchQuerySet().auto_query(filters['q'])
orm_filters["pk__in"] = [i.pk for i in sqs]
return orm_filters
Using PUT/DELETE/PATCH In Unsupported Places¶
Some places, like in certain browsers or hosts, don’t allow the PUT/DELETE/PATCH methods. In these environments, you can simulate those kinds of requests by providing an X-HTTP-Method-Override header. For example, to send a PATCH request over POST, you’d send a request like:
curl --dump-header - -H "Content-Type: application/json" -H "X-HTTP-Method-Override: PATCH" -X POST --data '{"title": "I Visited Grandma Today"}' http://localhost:8000/api/v1/entry/1/
Resource Methods¶
Handles the data, request dispatch and responding to requests.
Serialization/deserialization is handled “at the edges” (i.e. at the beginning/end of the request/response cycle) so that everything internally is Python data structures.
This class tries to be non-model specific, so it can be hooked up to other data sources, such as search results, files, other data, etc.
wrap_view¶
- Resource.wrap_view(self, view)¶
Wraps methods so they can be called in a more functional way as well as handling exceptions better.
Note that if BadRequest or an exception with a response attr are seen, there is special handling to either present a message back to the user or return the response traveling with the exception.
base_urls¶
- Resource.base_urls(self)¶
The standard URLs this Resource should respond to. These include the list, detail, schema & multiple endpoints by default.
Should return a list of individual URLconf lines (NOT wrapped in patterns).
override_urls¶
- Resource.override_urls(self)¶
Deprecated. Will be removed by v1.0.0. Please use Resource.prepend_urls instead.
prepend_urls¶
- Resource.prepend_urls(self)¶
A hook for adding your own URLs or matching before the default URLs. Useful for adding custom endpoints or overriding the built-in ones (from base_urls).
Should return a list of individual URLconf lines (NOT wrapped in patterns).
urls¶
- Resource.urls(self)¶
Property
The endpoints this Resource responds to. A combination of base_urls & override_urls.
Mostly a standard URLconf, this is suitable for either automatic use when registered with an Api class or for including directly in a URLconf should you choose to.
determine_format¶
- Resource.determine_format(self, request)¶
Used to determine the desired format.
Largely relies on tastypie.utils.mime.determine_format but here as a point of extension.
serialize¶
- Resource.serialize(self, request, data, format, options=None)¶
Given a request, data and a desired format, produces a serialized version suitable for transfer over the wire.
Mostly a hook, this uses the Serializer from Resource._meta.
deserialize¶
- Resource.deserialize(self, request, data, format='application/json')¶
Given a request, data and a format, deserializes the given data.
It relies on the request properly sending a CONTENT_TYPE header, falling back to application/json if not provided.
Mostly a hook, this uses the Serializer from Resource._meta.
alter_list_data_to_serialize¶
- Resource.alter_list_data_to_serialize(self, request, data)¶
A hook to alter list data just before it gets serialized & sent to the user.
Useful for restructuring/renaming aspects of the what’s going to be sent.
Should accommodate for a list of objects, generally also including meta data.
alter_detail_data_to_serialize¶
- Resource.alter_detail_data_to_serialize(self, request, data)¶
A hook to alter detail data just before it gets serialized & sent to the user.
Useful for restructuring/renaming aspects of the what’s going to be sent.
Should accommodate for receiving a single bundle of data.
alter_deserialized_list_data¶
- Resource.alter_deserialized_list_data(self, request, data)¶
A hook to alter list data just after it has been received from the user & gets deserialized.
Useful for altering the user data before any hydration is applied.
alter_deserialized_detail_data¶
- Resource.alter_deserialized_detail_data(self, request, data)¶
A hook to alter detail data just after it has been received from the user & gets deserialized.
Useful for altering the user data before any hydration is applied.
dispatch_list¶
- Resource.dispatch_list(self, request, **kwargs)¶
A view for handling the various HTTP methods (GET/POST/PUT/DELETE) over the entire list of resources.
Relies on Resource.dispatch for the heavy-lifting.
dispatch_detail¶
- Resource.dispatch_detail(self, request, **kwargs)¶
A view for handling the various HTTP methods (GET/POST/PUT/DELETE) on a single resource.
Relies on Resource.dispatch for the heavy-lifting.
dispatch¶
- Resource.dispatch(self, request_type, request, **kwargs)¶
Handles the common operations (allowed HTTP method, authentication, throttling, method lookup) surrounding most CRUD interactions.
remove_api_resource_names¶
- Resource.remove_api_resource_names(self, url_dict)¶
Given a dictionary of regex matches from a URLconf, removes api_name and/or resource_name if found.
This is useful for converting URLconf matches into something suitable for data lookup. For example:
Model.objects.filter(**self.remove_api_resource_names(matches))
method_check¶
- Resource.method_check(self, request, allowed=None)¶
Ensures that the HTTP method used on the request is allowed to be handled by the resource.
Takes an allowed parameter, which should be a list of lowercase HTTP methods to check against. Usually, this looks like:
# The most generic lookup.
self.method_check(request, self._meta.allowed_methods)
# A lookup against what's allowed for list-type methods.
self.method_check(request, self._meta.list_allowed_methods)
# A useful check when creating a new endpoint that only handles
# GET.
self.method_check(request, ['get'])
is_authorized¶
Handles checking of permissions to see if the user has authorization to GET, POST, PUT, or DELETE this resource. If object is provided, the authorization backend can apply additional row-level permissions checking.
is_authenticated¶
- Resource.is_authenticated(self, request)¶
Handles checking if the user is authenticated and dealing with unauthenticated users.
Mostly a hook, this uses class assigned to authentication from Resource._meta.
throttle_check¶
- Resource.throttle_check(self, request)¶
Handles checking if the user should be throttled.
Mostly a hook, this uses class assigned to throttle from Resource._meta.
log_throttled_access¶
- Resource.log_throttled_access(self, request)¶
Handles the recording of the user’s access for throttling purposes.
Mostly a hook, this uses class assigned to throttle from Resource._meta.
build_bundle¶
- Resource.build_bundle(self, obj=None, data=None, request=None)¶
Given either an object, a data dictionary or both, builds a Bundle for use throughout the dehydrate/hydrate cycle.
If no object is provided, an empty object from Resource._meta.object_class is created so that attempts to access bundle.obj do not fail.
build_filters¶
- Resource.build_filters(self, filters=None)¶
Allows for the filtering of applicable objects.
This needs to be implemented at the user level.
ModelResource includes a full working version specific to Django’s Models.
apply_sorting¶
- Resource.apply_sorting(self, obj_list, options=None)¶
Allows for the sorting of objects being returned.
This needs to be implemented at the user level.
ModelResource includes a full working version specific to Django’s Models.
get_bundle_detail_data¶
- Resource.get_bundle_detail_data(self, bundle)¶
Convenience method to return the detail_uri_name attribute off bundle.obj.
Usually just accesses bundle.obj.pk by default.
get_resource_uri¶
- Resource.get_resource_uri(self, bundle_or_obj=None, url_name='api_dispatch_list')¶
Handles generating a resource URI.
If the bundle_or_obj argument is not provided, it builds the URI for the list endpoint.
If the bundle_or_obj argument is provided, it builds the URI for the detail endpoint.
Return the generated URI. If that URI can not be reversed (not found in the URLconf), it will return an empty string.
resource_uri_kwargs¶
- Resource.resource_uri_kwargs(self, bundle_or_obj=None)¶
Handles generating a resource URI.
If the bundle_or_obj argument is not provided, it builds the URI for the list endpoint.
If the bundle_or_obj argument is provided, it builds the URI for the detail endpoint.
Return the generated URI. If that URI can not be reversed (not found in the URLconf), it will return None.
detail_uri_kwargs¶
- Resource.detail_uri_kwargs(self, bundle_or_obj)¶
This needs to be implemented at the user level.
Given a Bundle or an object, it returns the extra kwargs needed to generate a detail URI.
ModelResource includes a full working version specific to Django’s Models.
get_via_uri¶
- Resource.get_via_uri(self, uri, request=None)¶
This pulls apart the salient bits of the URI and populates the resource via a obj_get.
Optionally accepts a request.
If you need custom behavior based on other portions of the URI, simply override this method.
full_dehydrate¶
- Resource.full_dehydrate(self, bundle, for_list=False)¶
Given a bundle with an object instance, extract the information from it to populate the resource.
The for_list flag is used to control which fields are excluded by the use_in attribute.
dehydrate¶
- Resource.dehydrate(self, bundle)¶
A hook to allow a final manipulation of data once all fields/methods have built out the dehydrated data.
Useful if you need to access more than one dehydrated field or want to annotate on additional data.
Must return the modified bundle.
full_hydrate¶
- Resource.full_hydrate(self, bundle)¶
Given a populated bundle, distill it and turn it back into a full-fledged object instance.
hydrate¶
- Resource.hydrate(self, bundle)¶
A hook to allow a final manipulation of data once all fields/methods have built out the hydrated data.
Useful if you need to access more than one hydrated field or want to annotate on additional data.
Must return the modified bundle.
build_schema¶
- Resource.build_schema(self)¶
Returns a dictionary of all the fields on the resource and some properties about those fields.
Used by the schema/ endpoint to describe what will be available.
dehydrate_resource_uri¶
- Resource.dehydrate_resource_uri(self, bundle)¶
For the automatically included resource_uri field, dehydrate the URI for the given bundle.
Returns empty string if no URI can be generated.
generate_cache_key¶
- Resource.generate_cache_key(self, *args, **kwargs)¶
Creates a unique-enough cache key.
This is based off the current api_name/resource_name/args/kwargs.
get_object_list¶
- Resource.get_object_list(self, request)¶
A hook to allow making returning the list of available objects.
This needs to be implemented at the user level.
ModelResource includes a full working version specific to Django’s Models.
apply_authorization_limits¶
Allows the Authorization class to further limit the object list. Also a hook to customize per Resource.
Calls Authorization.apply_limits if available.
can_update¶
- Resource.can_update(self)¶
Checks to ensure put is within allowed_methods.
Used when hydrating related data.
apply_filters¶
- Resource.apply_filters(self, request, applicable_filters)¶
A hook to alter how the filters are applied to the object list.
This needs to be implemented at the user level.
ModelResource includes a full working version specific to Django’s Models.
obj_get_list¶
- Resource.obj_get_list(self, bundle, **kwargs)¶
Fetches the list of objects available on the resource.
This needs to be implemented at the user level.
ModelResource includes a full working version specific to Django’s Models.
cached_obj_get_list¶
- Resource.cached_obj_get_list(self, bundle, **kwargs)¶
A version of obj_get_list that uses the cache as a means to get commonly-accessed data faster.
obj_get¶
- Resource.obj_get(self, bundle, **kwargs)¶
Fetches an individual object on the resource.
This needs to be implemented at the user level. If the object can not be found, this should raise a NotFound exception.
ModelResource includes a full working version specific to Django’s Models.
cached_obj_get¶
- Resource.cached_obj_get(self, bundle, **kwargs)¶
A version of obj_get that uses the cache as a means to get commonly-accessed data faster.
obj_create¶
- Resource.obj_create(self, bundle, **kwargs)¶
Creates a new object based on the provided data.
This needs to be implemented at the user level.
ModelResource includes a full working version specific to Django’s Models.
lookup_kwargs_with_identifiers¶
- Resource.lookup_kwargs_with_identifiers(self, bundle, kwargs)¶
Kwargs here represent uri identifiers. Ex: /repos/<user_id>/<repo_name>/ We need to turn those identifiers into Python objects for generating lookup parameters that can find them in the DB.
obj_update¶
- Resource.obj_update(self, bundle, **kwargs)¶
Updates an existing object (or creates a new object) based on the provided data.
This needs to be implemented at the user level.
ModelResource includes a full working version specific to Django’s Models.
obj_delete_list¶
- Resource.obj_delete_list(self, bundle, **kwargs)¶
Deletes an entire list of objects.
This needs to be implemented at the user level.
ModelResource includes a full working version specific to Django’s Models.
obj_delete_list_for_update¶
- Resource.obj_delete_list_for_update(self, bundle, **kwargs)¶
Deletes an entire list of objects, specific to PUT list.
This needs to be implemented at the user level.
ModelResource includes a full working version specific to Django’s Models.
obj_delete¶
- Resource.obj_delete(self, bundle, **kwargs)¶
Deletes a single object.
This needs to be implemented at the user level.
ModelResource includes a full working version specific to Django’s Models.
create_response¶
- Resource.create_response(self, request, data, response_class=HttpResponse, **response_kwargs)¶
Extracts the common “which-format/serialize/return-response” cycle.
Mostly a useful shortcut/hook.
is_valid¶
- Resource.is_valid(self, bundle)¶
Handles checking if the data provided by the user is valid.
Mostly a hook, this uses class assigned to validation from Resource._meta.
If validation fails, an error is raised with the error messages serialized inside it.
rollback¶
- Resource.rollback(self, bundles)¶
Given the list of bundles, delete all objects pertaining to those bundles.
This needs to be implemented at the user level. No exceptions should be raised if possible.
ModelResource includes a full working version specific to Django’s Models.
get_list¶
- Resource.get_list(self, request, **kwargs)¶
Returns a serialized list of resources.
Calls obj_get_list to provide the data, then handles that result set and serializes it.
Should return a HttpResponse (200 OK).
get_detail¶
- Resource.get_detail(self, request, **kwargs)¶
Returns a single serialized resource.
Calls cached_obj_get/obj_get to provide the data, then handles that result set and serializes it.
Should return a HttpResponse (200 OK).
put_list¶
- Resource.put_list(self, request, **kwargs)¶
Replaces a collection of resources with another collection.
Calls delete_list to clear out the collection then obj_create with the provided the data to create the new collection.
Return HttpNoContent (204 No Content) if Meta.always_return_data = False (default).
Return HttpAccepted (202 Accepted) if Meta.always_return_data = True.
put_detail¶
- Resource.put_detail(self, request, **kwargs)¶
Either updates an existing resource or creates a new one with the provided data.
Calls obj_update with the provided data first, but falls back to obj_create if the object does not already exist.
If a new resource is created, return HttpCreated (201 Created). If Meta.always_return_data = True, there will be a populated body of serialized data.
If an existing resource is modified and Meta.always_return_data = False (default), return HttpNoContent (204 No Content). If an existing resource is modified and Meta.always_return_data = True, return HttpAccepted (202 Accepted).
post_list¶
- Resource.post_list(self, request, **kwargs)¶
Creates a new resource/object with the provided data.
Calls obj_create with the provided data and returns a response with the new resource’s location.
If a new resource is created, return HttpCreated (201 Created). If Meta.always_return_data = True, there will be a populated body of serialized data.
post_detail¶
- Resource.post_detail(self, request, **kwargs)¶
Creates a new subcollection of the resource under a resource.
This is not implemented by default because most people’s data models aren’t self-referential.
If a new resource is created, return HttpCreated (201 Created).
delete_list¶
- Resource.delete_list(self, request, **kwargs)¶
Destroys a collection of resources/objects.
Calls obj_delete_list.
If the resources are deleted, return HttpNoContent (204 No Content).
delete_detail¶
- Resource.delete_detail(self, request, **kwargs)¶
Destroys a single resource/object.
Calls obj_delete.
If the resource is deleted, return HttpNoContent (204 No Content). If the resource did not exist, return HttpNotFound (404 Not Found).
patch_list¶
- Resource.patch_list(self, request, **kwargs)¶
Updates a collection in-place.
The exact behavior of PATCH to a list resource is still the matter of some debate in REST circles, and the PATCH RFC isn’t standard. So the behavior this method implements (described below) is something of a stab in the dark. It’s mostly cribbed from GData, with a smattering of ActiveResource-isms and maybe even an original idea or two.
The PATCH format is one that’s similar to the response returned from a GET on a list resource:
{
"objects": [{object}, {object}, ...],
"deleted_objects": ["URI", "URI", "URI", ...],
}
For each object in objects:
- If the dict does not have a resource_uri key then the item is considered “new” and is handled like a POST to the resource list.
- If the dict has a resource_uri key and the resource_uri refers to an existing resource then the item is a update; it’s treated like a PATCH to the corresponding resource detail.
- If the dict has a resource_uri but the resource doesn’t exist, then this is considered to be a create-via-PUT.
Each entry in deleted_objects referes to a resource URI of an existing resource to be deleted; each is handled like a DELETE to the relevent resource.
In any case:
- If there’s a resource URI it must refer to a resource of this type. It’s an error to include a URI of a different resource.
- PATCH is all or nothing. If a single sub-operation fails, the entire request will fail and all resources will be rolled back.
- For PATCH to work, you must have put in your detail_allowed_methods setting.
- To delete objects via deleted_objects in a PATCH request you must have delete in your detail_allowed_methods setting.
patch_detail¶
- Resource.patch_detail(self, request, **kwargs)¶
Updates a resource in-place.
Calls obj_update.
If the resource is updated, return HttpAccepted (202 Accepted). If the resource did not exist, return HttpNotFound (404 Not Found).
ModelResource Methods¶
A subclass of Resource designed to work with Django’s Models.
This class will introspect a given Model and build a field list based on the fields found on the model (excluding relational fields).
Given that it is aware of Django’s ORM, it also handles the CRUD data operations of the resource.
should_skip_field¶
- ModelResource.should_skip_field(cls, field)¶
Class method
Given a Django model field, return if it should be included in the contributed ApiFields.
api_field_from_django_field¶
- ModelResource.api_field_from_django_field(cls, f, default=CharField)¶
Class method
Returns the field type that would likely be associated with each Django type.
get_fields¶
- ModelResource.get_fields(cls, fields=None, excludes=None)¶
Class method
Given any explicit fields to include and fields to exclude, add additional fields based on the associated model.
check_filtering¶
- ModelResource.check_filtering(self, field_name, filter_type='exact', filter_bits=None)¶
Given a field name, a optional filter type and an optional list of additional relations, determine if a field can be filtered on.
If a filter does not meet the needed conditions, it should raise an InvalidFilterError.
If the filter meets the conditions, a list of attribute names (not field names) will be returned.
build_filters¶
- ModelResource.build_filters(self, filters=None)¶
Given a dictionary of filters, create the necessary ORM-level filters.
Keys should be resource fields, NOT model fields.
Valid values are either a list of Django filter types (i.e. ['startswith', 'exact', 'lte']), the ALL constant or the ALL_WITH_RELATIONS constant.
At the declarative level:
filtering = {
'resource_field_name': ['exact', 'startswith', 'endswith', 'contains'],
'resource_field_name_2': ['exact', 'gt', 'gte', 'lt', 'lte', 'range'],
'resource_field_name_3': ALL,
'resource_field_name_4': ALL_WITH_RELATIONS,
...
}
Accepts the filters as a dict. None by default, meaning no filters.
apply_sorting¶
- ModelResource.apply_sorting(self, obj_list, options=None)¶
Given a dictionary of options, apply some ORM-level sorting to the provided QuerySet.
Looks for the order_by key and handles either ascending (just the field name) or descending (the field name with a - in front).
The field name should be the resource field, NOT model field.
apply_filters¶
- ModelResource.apply_filters(self, request, applicable_filters)¶
An ORM-specific implementation of apply_filters.
The default simply applies the applicable_filters as **kwargs, but should make it possible to do more advanced things.
get_object_list¶
- ModelResource.get_object_list(self, request)¶
A ORM-specific implementation of get_object_list.
Returns a QuerySet that may have been limited by other overrides.
obj_get_list¶
- ModelResource.obj_get_list(self, filters=None, **kwargs)¶
A ORM-specific implementation of obj_get_list.
Takes an optional filters dictionary, which can be used to narrow the query.
obj_get¶
- ModelResource.obj_get(self, **kwargs)¶
A ORM-specific implementation of obj_get.
Takes optional kwargs, which are used to narrow the query to find the instance.
obj_create¶
- ModelResource.obj_create(self, bundle, **kwargs)¶
A ORM-specific implementation of obj_create.
obj_update¶
- ModelResource.obj_update(self, bundle, **kwargs)¶
A ORM-specific implementation of obj_update.
obj_delete_list¶
- ModelResource.obj_delete_list(self, **kwargs)¶
A ORM-specific implementation of obj_delete_list.
Takes optional kwargs, which can be used to narrow the query.
obj_delete_list_for_update¶
- ModelResource.obj_delete_list_for_update(self, **kwargs)¶
A ORM-specific implementation of obj_delete_list_for_update.
Takes optional kwargs, which can be used to narrow the query.
obj_delete¶
- ModelResource.obj_delete(self, **kwargs)¶
A ORM-specific implementation of obj_delete.
Takes optional kwargs, which are used to narrow the query to find the instance.
rollback¶
- ModelResource.rollback(self, bundles)¶
A ORM-specific implementation of rollback.
Given the list of bundles, delete all models pertaining to those bundles.
save_m2m¶
- ModelResource.save_m2m(self, bundle)¶
Handles the saving of related M2M data.
Due to the way Django works, the M2M data must be handled after the main instance, which is why this isn’t a part of the main save bits.
Currently slightly inefficient in that it will clear out the whole relation and recreate the related data as needed.
Bundles¶
What Are Bundles?¶
Bundles are a small abstraction that allow Tastypie to pass data between resources. This allows us not to depend on passing request to every single method (especially in places where this would be overkill). It also allows resources to work with data coming into the application paired together with an unsaved instance of the object in question. Finally, it aids in keeping Tastypie more thread-safe.
Think of it as package of user data & an object instance (either of which are optionally present).
Attributes¶
All data within a bundle can be optional, especially depending on how it’s being used. If you write custom code using Bundle, make sure appropriate guards are in place.
obj¶
Either a Python object or None.
Usually a Django model, though it may/may not have been saved already.
data¶
Always a plain Python dictionary of data. If not provided, it will be empty.
request¶
Either the Django request that’s part of the issued request or an empty HttpRequest if it wasn’t provided.
Api¶
In terms of a REST-style architecture, the “api” is a collection of resources. In Tastypie, the Api gathers together the Resources & provides a nice way to use them as a set. It handles many of the URLconf details for you, provides a helpful “top-level” view to show what endpoints are available & some extra URL resolution juice.
Quick Start¶
A sample api definition might look something like (usually located in a URLconf):
from tastypie.api import Api
from myapp.api.resources import UserResource, EntryResource
v1_api = Api(api_name='v1')
v1_api.register(UserResource())
v1_api.register(EntryResource())
# Standard bits...
urlpatterns = patterns('',
(r'^api/', include(v1_api.urls)),
)
Api Methods¶
Implements a registry to tie together the various resources that make up an API.
Especially useful for navigation, HATEOAS and for providing multiple versions of your API.
Optionally supplying api_name allows you to name the API. Generally, this is done with version numbers (i.e. v1, v2, etc.) but can be named any string.
register¶
- Api.register(self, resource, canonical=True):
Registers an instance of a Resource subclass with the API.
Optionally accept a canonical argument, which indicates that the resource being registered is the canonical variant. Defaults to True.
canonical_resource_for¶
- Api.canonical_resource_for(self, resource_name):
Returns the canonical resource for a given resource_name.
override_urls¶
- Api.override_urls(self):
Deprecated. Will be removed by v1.0.0. Please use Api.prepend_urls instead.
prepend_urls¶
- Api.prepend_urls(self):
A hook for adding your own URLs or matching before the default URLs. Useful for adding custom endpoints or overriding the built-in ones.
Should return a list of individual URLconf lines (NOT wrapped in patterns).
urls¶
- Api.urls(self):
Property
Provides URLconf details for the Api and all registered Resources beneath it.
top_level¶
- Api.top_level(self, request, api_name=None):
A view that returns a serialized list of all resources registers to the Api. Useful for discovery.
Resource Fields¶
When designing an API, an important component is defining the representation of the data you’re presenting. Like Django models, you can control the representation of a Resource using fields. There are a variety of fields for various types of data.
Quick Start¶
For the impatient:
from tastypie import fields, utils
from tastypie.resources import Resource
from myapp.api.resources import ProfileResource, NoteResource
class PersonResource(Resource):
name = fields.CharField(attribute='name')
age = fields.IntegerField(attribute='years_old', null=True)
created = fields.DateTimeField(readonly=True, help_text='When the person was created', default=utils.now)
is_active = fields.BooleanField(default=True)
profile = fields.ToOneField(ProfileResource, 'profile')
notes = fields.ToManyField(NoteResource, 'notes', full=True)
Standard Data Fields¶
All standard data fields have a common base class ApiField which handles the basic implementation details.
Note
You should not use the ApiField class directly. Please use one of the subclasses that is more correct for your data.
Common Field Options¶
All ApiField objects accept the following options.
attribute¶
- ApiField.attribute¶
A string naming an instance attribute of the object wrapped by the Resource. The attribute will be accessed during the dehydrate or or written during the hydrate.
Defaults to None, meaning data will be manually accessed.
default¶
- ApiField.default¶
Provides default data when the object being dehydrated/hydrated has no data on the field.
Defaults to tastypie.fields.NOT_PROVIDED.
null¶
- ApiField.null¶
Indicates whether or not a None is allowable data on the field. Defaults to False.
blank¶
- ApiField.blank¶
Indicates whether or not data may be omitted on the field. Defaults to False.
This is useful for allowing the user to omit data that you can populate based on the request, such as the user or site to associate a record with.
readonly¶
- ApiField.readonly¶
Indicates whether the field is used during the hydrate or not. Defaults to False.
Field Types¶
DateField¶
A date field.
DateTimeField¶
A datetime field.
DecimalField¶
A decimal field.
DictField¶
A dictionary field.
FloatField¶
A floating point field.
IntegerField¶
An integer field.
Covers models.IntegerField, models.PositiveIntegerField, models.PositiveSmallIntegerField and models.SmallIntegerField.
ListField¶
A list field.
TimeField¶
A time field.
Relationship Fields¶
Provides access to data that is related within the database.
The RelatedField base class is not intended for direct use but provides functionality that ToOneField and ToManyField build upon.
The contents of this field actually point to another Resource, rather than the related object. This allows the field to represent its data in different ways.
The abstractions based around this are “leaky” in that, unlike the other fields provided by tastypie, these fields don’t handle arbitrary objects very well. The subclasses use Django’s ORM layer to make things go, though there is no ORM-specific code at this level.
Common Field Options¶
In addition to the common attributes for all ApiField, relationship fields accept the following.
full¶
- RelatedField.full¶
Indicates how the related Resource will appear post-dehydrate. If False, the related Resource will appear as a URL to the endpoint of that resource. If True, the result of the sub-resource’s dehydrate will be included in full. You can further control post-dehydrate behaviour when requesting a resource or a list of resources by setting full_list and full_detail.
full_list¶
- RelatedField.full_list¶
Indicates how the related Resource will appear post-dehydrate when requesting a list of resources. The value is one of True, False or a callable that accepts a bundle and returns True or False. If False, the related Resource will appear as a URL to the endpoint of that resource if accessing a list of resources. If True and full is also True, the result of thesub-resource’s dehydrate will be included in full. Default is True
full_detail¶
- RelatedField.full_detail¶
Indicates how the related Resource will appear post-dehydrate when requesting a single resource. The value is one of True, False or a callable that accepts a bundle and returns True or False. If False, the related Resource will appear as a URL to the endpoint of that resource if accessing a specific resources. If True and full is also True, the result of thesub-resource’s dehydrate will be included in full. Default is True
Field Types¶
ToOneField¶
Provides access to related data via foreign key.
This subclass requires Django’s ORM layer to work properly.
OneToOneField¶
An alias to ToOneField for those who prefer to mirror django.db.models.
ForeignKey¶
An alias to ToOneField for those who prefer to mirror django.db.models.
ToManyField¶
Provides access to related data via a join table.
This subclass requires Django’s ORM layer to work properly.
This field also has special behavior when dealing with attribute in that it can take a callable. For instance, if you need to filter the reverse relation, you can do something like:
subjects = fields.ToManyField(SubjectResource, attribute=lambda bundle: Subject.objects.filter(notes=bundle.obj, name__startswith='Personal'))
Note that the hydrate portions of this field are quite different than any other field. hydrate_m2m actually handles the data and relations. This is due to the way Django implements M2M relationships.
ManyToManyField¶
An alias to ToManyField for those who prefer to mirror django.db.models.
OneToManyField¶
An alias to ToManyField for those who prefer to mirror django.db.models.
Caching¶
When adding an API to your site, it’s important to understand that most consumers of the API will not be people, but instead machines. This means that the traditional “fetch-read-click” cycle is no longer measured in minutes but in seconds or milliseconds.
As such, caching is a very important part of the deployment of your API. Tastypie ships with two classes to make working with caching easier. These caches store at the object level, reducing access time on the database.
However, it’s worth noting that these do NOT cache serialized representations. For heavy traffic, we’d encourage the use of a caching proxy, especially Varnish, as it shines under this kind of usage. It’s far faster than Django views and already neatly handles most situations.
The first section below demonstrates how to cache at the Django level, reducing the amount of work required to satisfy a request. In many cases your API serves web browsers or is behind by a caching proxy such as Varnish and it is possible to set HTTP Cache-Control headers to avoid issuing a request to your application at all. This is discussed in the HTTP Cache-Control section below.
Usage¶
Using these classes is simple. Simply provide them (or your own class) as a Meta option to the Resource in question. For example:
from django.contrib.auth.models import User
from tastypie.cache import SimpleCache
from tastypie.resources import ModelResource
class UserResource(ModelResource):
class Meta:
queryset = User.objects.all()
resource_name = 'auth/user'
excludes = ['email', 'password', 'is_superuser']
# Add it here.
cache = SimpleCache(timeout=10)
Caching Options¶
Tastypie ships with the following Cache classes:
NoCache¶
The no-op cache option, this does no caching but serves as an api-compatible plug. Very useful for development.
SimpleCache¶
This option does basic object caching, attempting to find the object in the cache & writing the object to the cache. It uses Django’s current CACHE_BACKEND to store cached data. The constructor receive a timeout parameter to control per-resource the default timeout for the cache.
Implementing Your Own Cache¶
Implementing your own Cache class is as simple as subclassing NoCache and overriding the get & set methods. For example, a json-backed cache might look like:
import json
from django.conf import settings
from tastypie.cache import NoCache
class JSONCache(NoCache):
def _load(self):
data_file = open(settings.TASTYPIE_JSON_CACHE, 'r')
return json.load(data_file)
def _save(self, data):
data_file = open(settings.TASTYPIE_JSON_CACHE, 'w')
return json.dump(data, data_file)
def get(self, key):
data = self._load()
return data.get(key, None)
def set(self, key, value, timeout=60):
data = self._load()
data[key] = value
self._save(data)
Note that this is NOT necessarily an optimal solution, but is simply demonstrating how one might go about implementing your own Cache.
HTTP Cache-Control¶
The HTTP protocol defines a Cache-Control header, which can be used to tell clients and intermediaries who is allowed to cache a response and for how long. Mark Nottingham has a general caching introduction and the Django cache documentation describes how to set caching-related headers in your code. The range of possible options is beyond the scope of this documentation, but it’s important to know that, by default, Tastypie will prevent responses from being cached to ensure that clients always receive current information.
To override the default no-cache response, your Resource should ensure that your cache class implements cache_control. The default SimpleCache does this by default. It uses the timeout passed to the initialization as the max-age and s-maxage. By default, it does not claim to know if the results should be public or privately cached but this can be changed by passing either a public=True or a private=True to the initialization of the SimpleClass.
Behind the scenes, the return value from the cache_control method is passed to the cache_control helper provided by Django. If you wish to add your own methods to it, you can do so by overloading the cache_control method and modifying the dictionary it returns.:
from tastypie.cache import SimpleCache
class NoTransformCache(SimpleCache):
def cache_control(self):
control = super(NoTransformCache, self).cache_control()
control.update({"no_transform": True})
return control
HTTP Vary¶
The HTTP protocol defines a Vary header, which can be used to tell clients and intermediaries on what headers your response varies. This allows clients to store a correct response for each type. By default, Tastypie will send the Vary: Accept header so that a seperate response is cached for each Content-Type. However, if you wish to change this, simply pass a list to the varies kwarg of any Cache class.
It is important to note that if a list is passed, Tastypie not automatically include the Vary: Accept and you should include it as a member of your list.:
class ExampleResource(Resource):
class Meta:
cache = SimpleCache(varies=["Accept", "Cookie"])
Validation¶
Validation allows you to ensure that the data being submitted by the user is appropriate for storage. This can range from simple type checking on up to complex validation that compares different fields together.
If the data is valid, an empty dictionary is returned and processing continues as normal. If the data is invalid, a dictionary of error messages (keys being the field names, values being a list of error messages) is immediately returned to the user, serialized in the format they requested.
Usage¶
Using these classes is simple. Simply provide them (or your own class) as a Meta option to the Resource in question. For example:
from django.contrib.auth.models import User
from tastypie.validation import Validation
from tastypie.resources import ModelResource
class UserResource(ModelResource):
class Meta:
queryset = User.objects.all()
resource_name = 'auth/user'
excludes = ['email', 'password', 'is_superuser']
# Add it here.
validation = Validation()
Validation Options¶
Tastypie ships with the following Validation classes:
Validation¶
The no-op validation option, the data submitted is always considered to be valid.
This is the default class hooked up to Resource/ModelResource.
FormValidation¶
A more complex form of validation, this class accepts a form_class argument to its constructor. You supply a Django Form (or ModelForm, though save will never get called) and Tastypie will verify the data in the Bundle against the form.
This class DOES NOT alter the data sent, only verifies it. If you want to alter the data, please use the CleanedDataFormValidation class instead.
Warning
Data in the bundle must line up with the fieldnames in the Form. If they do not, you’ll need to either munge the data or change your form.
Usage looks like:
from django import forms
class NoteForm(forms.Form):
title = forms.CharField(max_length=100)
slug = forms.CharField(max_length=50)
content = forms.CharField(required=False, widget=forms.Textarea)
is_active = forms.BooleanField()
form = FormValidation(form_class=NoteForm)
CleanedDataFormValidation¶
Similar to the FormValidation class, this uses a Django Form to handle validation. However, it will use the form.cleaned_data to replace the bundle data sent by user! Usage is identical to FormValidation.
Implementing Your Own Validation¶
Implementing your own Validation classes is a simple process. The constructor can take whatever **kwargs it needs (if any). The only other method to implement is the is_valid method:
from tastypie.validation import Validation
class AwesomeValidation(Validation):
def is_valid(self, bundle, request=None):
if not bundle.data:
return {'__all__': 'Not quite what I had in mind.'}
errors = {}
for key, value in bundle.data.items():
if not isinstance(value, basestring):
continue
if not 'awesome' in value:
errors[key] = ['NOT ENOUGH AWESOME. NEEDS MORE.']
return errors
Under this validation, every field that’s a string is checked for the word ‘awesome’. If it’s not in the string, it’s an error.
Authentication¶
Authentication is the component needed to verify who a certain user is and to validate their access to the API.
Authentication answers the question “Who is this person?” This usually involves requiring credentials, such as an API key or username/password or oAuth tokens.
Usage¶
Using these classes is simple. Simply provide them (or your own class) as a Meta option to the Resource in question. For example:
from django.contrib.auth.models import User
from tastypie.authentication import BasicAuthentication
from tastypie.resources import ModelResource
class UserResource(ModelResource):
class Meta:
queryset = User.objects.all()
resource_name = 'auth/user'
excludes = ['email', 'password', 'is_superuser']
# Add it here.
authentication = BasicAuthentication()
Authentication Options¶
Tastypie ships with the following Authentication classes:
Authentication¶
The no-op authentication option, the client is always allowed through. Very useful for development and read-only APIs.
BasicAuthentication¶
This authentication scheme uses HTTP Basic Auth to check a user’s credentials. The username is their django.contrib.auth.models.User username (assuming it is present) and their password should also correspond to that entry.
Warning
If you’re using Apache & mod_wsgi, you will need to enable WSGIPassAuthorization On. See this post for details.
ApiKeyAuthentication¶
As an alternative to requiring sensitive data like a password, the ApiKeyAuthentication allows you to collect just username & a machine-generated api key. Tastypie ships with a special Model just for this purpose, so you’ll need to ensure tastypie is in INSTALLED_APPS and that the model’s database tables have been created (e.g. via django-admin.py syncdb).
To use this mechanism, the end user can either specify an Authorization header or pass the username/api_key combination as GET/POST parameters. Examples:
# As a header
# Format is ``Authorization: ApiKey <username>:<api_key>
Authorization: ApiKey daniel:204db7bcfafb2deb7506b89eb3b9b715b09905c8
# As GET params
http://127.0.0.1:8000/api/v1/entries/?username=daniel&api_key=204db7bcfafb2deb7506b89eb3b9b715b09905c8
Tastypie includes a signal function you can use to auto-create ApiKey objects. Hooking it up looks like:
from django.contrib.auth.models import User
from django.db import models
from tastypie.models import create_api_key
models.signals.post_save.connect(create_api_key, sender=User)
Warning
If you’re using Apache & mod_wsgi, you will need to enable WSGIPassAuthorization On, otherwise mod_wsgi strips out the Authorization header. See this post for details (even though it only mentions Basic auth).
Note
In some cases it may be useful to make the ApiKey model an abstract base class. To enable this, set settings.TASTYPIE_ABSTRACT_APIKEY to True. See the documentation for this setting for more information.
SessionAuthentication¶
This authentication scheme uses the built-in Django sessions to check if a user is logged. This is typically useful when used by Javascript on the same site as the API is hosted on.
It requires that the user has logged in & has an active session. They also must have a valid CSRF token.
DigestAuthentication¶
This authentication scheme uses HTTP Digest Auth to check a user’s credentials. The username is their django.contrib.auth.models.User username (assuming it is present) and their password should be their machine-generated api key. As with ApiKeyAuthentication, tastypie should be included in INSTALLED_APPS.
Warning
If you’re using Apache & mod_wsgi, you will need to enable WSGIPassAuthorization On. See this post for details (even though it only mentions Basic auth).
OAuthAuthentication¶
Handles OAuth, which checks a user’s credentials against a separate service. Currently verifies against OAuth 1.0a services.
This does NOT provide OAuth authentication in your API, strictly consumption.
Warning
If you’re used to in-browser OAuth flow (click a “Sign In” button, get redirected, login on remote service, get redirected back), this isn’t the same. Most prominently, expecting that would cause API clients to have to use tools like mechanize to fill in forms, which would be difficult.
This authentication expects that you’re already followed some sort of OAuth flow & that the credentials (Nonce/token/etc) are simply being passed to it. It merely checks that the credentials are valid. No requests are made to remote services as part of this authentication class.
MultiAuthentication¶
This authentication class actually wraps any number of other authentication classes, attempting each until successfully authenticating. For example:
from django.contrib.auth.models import User
from tastypie.authentication import BasicAuthentication, ApiKeyAuthentication, MultiAuthentication
from tastypie.authorization import DjangoAuthorization
from tastypie.resources import ModelResource
class UserResource(ModelResource):
class Meta:
queryset = User.objects.all()
resource_name = 'auth/user'
excludes = ['email', 'password', 'is_superuser']
authentication = MultiAuthentication(BasicAuthentication(), ApiKeyAuthentication())
authorization = DjangoAuthorization()
In the case of an authentication returning a customized HttpUnauthorized, MultiAuthentication defaults to the first returned one. Authentication schemes that need to control the response, such as the included BasicAuthentication and DigestAuthentication, should be placed first.
Implementing Your Own Authentication/Authorization¶
Implementing your own Authentication classes is a simple process. Authentication has two methods to override (one of which is optional but recommended to be customized):
from tastypie.authentication import Authentication
class SillyAuthentication(Authentication):
def is_authenticated(self, request, **kwargs):
if 'daniel' in request.user.username:
return True
return False
# Optional but recommended
def get_identifier(self, request):
return request.user.username
Under this scheme, only users with ‘daniel’ in their username will be allowed in.
Authorization¶
Authorization is the component needed to verify what someone can do with the resources within an API.
Authorization answers the question “Is permission granted for this user to take this action?” This usually involves checking permissions such as Create/Read/Update/Delete access, or putting limits on what data the user can access.
Usage¶
Using these classes is simple. Simply provide them (or your own class) as a Meta option to the Resource in question. For example:
from django.contrib.auth.models import User
from tastypie.authorization import DjangoAuthorization
from tastypie.resources import ModelResource
class UserResource(ModelResource):
class Meta:
queryset = User.objects.all()
resource_name = 'auth/user'
excludes = ['email', 'password', 'is_superuser']
# Add it here.
authorization = DjangoAuthorization()
Authorization Options¶
Tastypie ships with the following Authorization classes:
Authorization¶
The no-op authorization option, no permissions checks are performed.
Warning
This is a potentially dangerous option, as it means ANY recognized user can modify ANY data they encounter in the API. Be careful who you trust.
ReadOnlyAuthorization¶
This authorization class only permits reading data, regardless of what the Resource might think is allowed. This is the default Authorization class and the safe option.
DjangoAuthorization¶
The most advanced form of authorization, this checks the permission a user has granted to them (via django.contrib.auth.models.Permission). In conjunction with the admin, this is a very effective means of control.
The Authorization API¶
An Authorization-compatible class implements the following methods:
- read_list
- read_detail
- create_list
- create_detail
- update_list
- update_detail
- delete_list
- delete_detail
Each method takes two parameters, object_list & bundle.
object_list is the collection of objects being processed as part of the request. FILTERING & other restrictions to the set will have already been applied prior to this call.
bundle is the populated Bundle object for the request. You’ll likely frequently be accessing bundle.request.user, though raw access to the data can be helpful.
What you return from the method varies based on the type of method.
Return Values: The List Case¶
In the case of the *_list methods, you’ll want to filter the object_list & return only the objects the user has access to.
Returning an empty list simply won’t allow the action to be applied to any objects. However, they will not get a HTTP error status code.
If you’d rather they received an unauthorized status code, raising Unauthorized will return a HTTP 401.
Return Values: The Detail Case¶
In the case of the *_detail methods, you’ll have access to the object_list (so you know if a given object fits within the overall set), BUT you’ll want to be inspecting bundle.obj & either returning True if they should be allowed to continue or raising the Unauthorized exception if not.
Raising Unauthorized will cause a HTTP 401 error status code in the response.
Implementing Your Own Authorization¶
Implementing your own Authorization classes is a relatively simple process. Anything that is API-compatible is acceptable, only the method names matter to Tastypie.
An example implementation of a user only being able to “their” objects might look like:
from tastypie.authorization import Authorization
from tastypie.exceptions import Unauthorized
class UserObjectsOnlyAuthorization(Authorization):
def read_list(self, object_list, bundle):
# This assumes a ``QuerySet`` from ``ModelResource``.
return object_list.filter(user=bundle.request.user)
def read_detail(self, object_list, bundle):
# Is the requested object owned by the user?
return bundle.obj.user == bundle.request.user
def create_list(self, object_list, bundle):
# Assuming their auto-assigned to ``user``.
return object_list
def create_detail(self, object_list, bundle):
return bundle.obj.user == bundle.request.user
def update_list(self, object_list, bundle):
allowed = []
# Since they may not all be saved, iterate over them.
for obj in object_list:
if obj.user == bundle.request.user:
allowed.append(obj)
return allowed
def update_detail(self, object_list, bundle):
return bundle.obj.user == bundle.request.user
def delete_list(self, object_list, bundle):
# Sorry user, no deletes for you!
raise Unauthorized("Sorry, no deletes.")
def delete_detail(self, object_list, bundle):
raise Unauthorized("Sorry, no deletes.")
Serialization¶
Serialization can be one of the most contentious areas of an API. Everyone has their own requirements, their own preferred output format & the desire to have control over what is returned.
As a result, Tastypie ships with a serializer that tries to meet the basic needs of most use cases, and the flexibility to go outside of that when you need to.
Usage¶
Using this class is simple. It is the default option on all Resource classes unless otherwise specified. The following code is identical to the defaults but demonstrate how you could use your own serializer:
from django.contrib.auth.models import User
from tastypie.resources import ModelResource
from tastypie.serializers import Serializer
class UserResource(ModelResource):
class Meta:
queryset = User.objects.all()
resource_name = 'auth/user'
excludes = ['email', 'password', 'is_superuser']
# Add it here.
serializer = Serializer()
Configuring Allowed Formats¶
The default Serializer supports the following formats:
- json
- jsonp (Disabled by default)
- xml
- yaml
- html
- plist (see http://explorapp.com/biplist/)
Not everyone wants to install or support all the serialization options. If you would list to customize the list of supported formats for your entire site the TASTYPIE_DEFAULT_FORMATS setting allows you to set the default format list site-wide.
If you wish to change the format list for a specific resource, you can pass the list of supported formats using the formats= kwarg. For example, to provide only JSON & binary plist serialization:
from django.contrib.auth.models import User
from tastypie.resources import ModelResource
from tastypie.serializers import Serializer
class UserResource(ModelResource):
class Meta:
queryset = User.objects.all()
resource_name = 'auth/user'
excludes = ['email', 'password', 'is_superuser']
serializer = Serializer(formats=['json', 'plist'])
Enabling the built-in (but disabled by default) JSONP support looks like:
from django.contrib.auth.models import User
from tastypie.resources import ModelResource
from tastypie.serializers import Serializer
class UserResource(ModelResource):
class Meta:
queryset = User.objects.all()
resource_name = 'auth/user'
excludes = ['email', 'password', 'is_superuser']
serializer = Serializer(formats=['json', 'jsonp', 'xml', 'yaml', 'html', 'plist'])
Serialization Security¶
Deserialization of input from unknown or untrusted sources is an intrinsically risky endeavor and vulnerabilities are regularly found in popular format libraries. Tastypie adopts and recommends the following approach:
Support the minimum required set of formats in your application. If you do not require a format, it’s much safer to disable it completely. See TASTYPIE_DEFAULT_FORMATS setting.
Some parsers offer additional safety check for use with untrusted content. The standard Tastypie Serializer attempts to be secure by default using features like PyYAML’s safe_load function and the defusedxml security wrapper for popular Python XML libraries.
Note
Tastypie’s precautions only apply to the default Serializer. If you have written your own serializer subclass we strongly recommend that you review your code to ensure that it uses the same precautions.
If backwards compatibility forces you to load files which require risky features we strongly recommend enabling those features only for the necessary resources and making your authorization checks as strict as possible. The Authentication and Authorization checks happen before deserialization so, for example, a resource which only allowed POST or PUT requests to be made by administrators is far less exposed than a general API open to the unauthenticated internet.
Implementing Your Own Serializer¶
There are several different use cases here. We’ll cover simple examples of wanting a tweaked format & adding a different format.
To tweak a format, simply override it’s to_<format> & from_<format> methods. So adding the server time to all output might look like so:
import time
from django.utils import simplejson
from django.core.serializers import json
from tastypie.serializers import Serializer
class CustomJSONSerializer(Serializer):
def to_json(self, data, options=None):
options = options or {}
data = self.to_simple(data, options)
# Add in the current time.
data['requested_time'] = time.time()
return simplejson.dumps(data, cls=json.DjangoJSONEncoder, sort_keys=True)
def from_json(self, content):
data = simplejson.loads(content)
if 'requested_time' in data:
# Log the request here...
pass
return data
In the case of adding a different format, let’s say you want to add a CSV output option to the existing set. Your Serializer subclass might look like:
import csv
import StringIO
from tastypie.serializers import Serializer
class CSVSerializer(Serializer):
formats = ['json', 'jsonp', 'xml', 'yaml', 'html', 'plist', 'csv']
content_types = {
'json': 'application/json',
'jsonp': 'text/javascript',
'xml': 'application/xml',
'yaml': 'text/yaml',
'html': 'text/html',
'plist': 'application/x-plist',
'csv': 'text/csv',
}
def to_csv(self, data, options=None):
options = options or {}
data = self.to_simple(data, options)
raw_data = StringIO.StringIO()
# Untested, so this might not work exactly right.
for item in data:
writer = csv.DictWriter(raw_data, item.keys(), extrasaction='ignore')
writer.write(item)
return raw_data
def from_csv(self, content):
raw_data = StringIO.StringIO(content)
data = []
# Untested, so this might not work exactly right.
for item in csv.DictReader(raw_data):
data.append(item)
return data
Serializer Methods¶
A swappable class for serialization.
This handles most types of data as well as the following output formats:
* json
* jsonp
* xml
* yaml
* html
* plist
It was designed to make changing behavior easy, either by overridding the various format methods (i.e. to_json), by changing the formats/content_types options or by altering the other hook methods.
get_mime_for_format¶
- Serializer.get_mime_for_format(self, format):
Given a format, attempts to determine the correct MIME type.
If not available on the current Serializer, returns application/json by default.
format_datetime¶
- Serializer.format_datetime(data):
A hook to control how datetimes are formatted.
Can be overridden at the Serializer level (datetime_formatting) or globally (via settings.TASTYPIE_DATETIME_FORMATTING).
Default is iso-8601, which looks like “2010-12-16T03:02:14”.
format_date¶
- Serializer.format_date(data):
A hook to control how dates are formatted.
Can be overridden at the Serializer level (datetime_formatting) or globally (via settings.TASTYPIE_DATETIME_FORMATTING).
Default is iso-8601, which looks like “2010-12-16”.
format_time¶
- Serializer.format_time(data):
A hook to control how times are formatted.
Can be overridden at the Serializer level (datetime_formatting) or globally (via settings.TASTYPIE_DATETIME_FORMATTING).
Default is iso-8601, which looks like “03:02:14”.
serialize¶
- Serializer.serialize(self, bundle, format='application/json', options={}):
Given some data and a format, calls the correct method to serialize the data and returns the result.
deserialize¶
- Serializer.deserialize(self, content, format='application/json'):
Given some data and a format, calls the correct method to deserialize the data and returns the result.
to_simple¶
- Serializer.to_simple(self, data, options):
For a piece of data, attempts to recognize it and provide a simplified form of something complex.
This brings complex Python data structures down to native types of the serialization format(s).
to_etree¶
- Serializer.to_etree(self, data, options=None, name=None, depth=0):
Given some data, converts that data to an etree.Element suitable for use in the XML output.
from_etree¶
- Serializer.from_etree(self, data):
Not the smartest deserializer on the planet. At the request level, it first tries to output the deserialized subelement called “object” or “objects” and falls back to deserializing based on hinted types in the XML element attribute “type”.
to_json¶
- Serializer.to_json(self, data, options=None):
Given some Python data, produces JSON output.
from_json¶
- Serializer.from_json(self, content):
Given some JSON data, returns a Python dictionary of the decoded data.
to_jsonp¶
- Serializer.to_jsonp(self, data, options=None):
Given some Python data, produces JSON output wrapped in the provided callback.
from_xml¶
- Serializer.from_xml(self, content):
Given some XML data, returns a Python dictionary of the decoded data.
to_yaml¶
- Serializer.to_yaml(self, data, options=None):
Given some Python data, produces YAML output.
from_yaml¶
- Serializer.from_yaml(self, content):
Given some YAML data, returns a Python dictionary of the decoded data.
to_plist¶
- Serializer.to_plist(self, data, options=None):
Given some Python data, produces binary plist output.
from_plist¶
- Serializer.from_plist(self, content):
Given some binary plist data, returns a Python dictionary of the decoded data.
to_html¶
- Serializer.to_html(self, data, options=None):
Reserved for future usage.
The desire is to provide HTML output of a resource, making an API available to a browser. This is on the TODO list but not currently implemented.
from_html¶
- Serializer.from_html(self, content):
Reserved for future usage.
The desire is to handle form-based (maybe Javascript?) input, making an API available to a browser. This is on the TODO list but not currently implemented.
Throttling¶
Sometimes, the client on the other end may request data too frequently or you have a business use case that dictates that the client should be limited to a certain number of requests per hour.
For this, Tastypie includes throttling as a way to limit the number of requests in a timeframe.
Usage¶
To specify a throttle, add the Throttle class to the Meta class on the Resource:
from django.contrib.auth.models import User
from tastypie.resources import ModelResource
from tastypie.throttle import BaseThrottle
class UserResource(ModelResource):
class Meta:
queryset = User.objects.all()
resource_name = 'auth/user'
excludes = ['email', 'password', 'is_superuser']
# Add it here.
throttle = BaseThrottle(throttle_at=100)
Throttle Options¶
Each of the Throttle classes accepts the following initialization arguments:
- throttle_at - the number of requests at which the user should be throttled. Default is 150 requests.
- timeframe - the length of time (in seconds) in which the user make up to the throttle_at requests. Default is 3600 seconds ( 1 hour).
- expiration - the length of time to retain the times the user has accessed the api in the cache. Default is 604800 (1 week).
Tastypie ships with the following Throttle classes:
BaseThrottle¶
The no-op throttle option, this does no throttling but implements much of the common logic and serves as an api-compatible plug. Very useful for development.
CacheThrottle¶
This uses just the cache to manage throttling. Fast but prone to cache misses and/or cache restarts.
CacheDBThrottle¶
A write-through option that uses the cache first & foremost, but also writes through to the database to persist access times. Useful for logging client accesses & with RAM-only caches.
Implementing Your Own Throttle¶
Writing a Throttle class is not quite as simple as the other components. There are two important methods, should_be_throttled & accessed. The should_be_throttled method dictates whether or not the client should be throttled. The accessed method allows for the recording of the hit to the API.
An example of a subclass might be:
import random
from tastypie.throttle import BaseThrottle
class RandomThrottle(BaseThrottle):
def should_be_throttled(self, identifier, **kwargs):
if random.randint(0, 10) % 2 == 0:
return True
return False
def accessed(self, identifier, **kwargs):
pass
This throttle class would pick a random number between 0 & 10. If the number is even, their request is allowed through; otherwise, their request is throttled & rejected.
Paginator¶
Similar to Django’s Paginator, Tastypie includes a Paginator object which limits result sets down to sane amounts for passing to the client.
This is used in place of Django’s Paginator due to the way pagination works. limit & offset (tastypie) are used in place of page (Django) so none of the page-related calculations are necessary.
This implementation also provides additional details like the total_count of resources seen and convenience links to the previous/next pages of data as available.
Usage¶
Using this class is simple, but slightly different than the other classes used by Tastypie. Like the others, you provide the Paginator (or your own subclass) as a Meta option to the Resource in question. Unlike the others, you provide the class, NOT an instance. For example:
from django.contrib.auth.models import User
from tastypie.paginator import Paginator
from tastypie.resources import ModelResource
class UserResource(ModelResource):
class Meta:
queryset = User.objects.all()
resource_name = 'auth/user'
excludes = ['email', 'password', 'is_superuser']
# Add it here.
paginator_class = Paginator
Warning
The default paginator contains the total_count value, which shows how many objects are in the underlying object list.
Obtaining this data from the database may be inefficient, especially with large datasets, and unfiltered API requests.
See http://wiki.postgresql.org/wiki/Slow_Counting and http://www.wikivs.com/wiki/MySQL_vs_PostgreSQL#COUNT.28.2A.29 for reference, on why this may be a problem when using PostgreSQL and MySQL’s InnoDB engine.
Here’s an example solution to this problem.
Implementing Your Own Paginator¶
Adding other features to a paginator usually consists of overriding one of the built-in methods. For instance, adding a page number to the output might look like:
from tastypie.paginator import Paginator
class PageNumberPaginator(Paginator):
def page(self):
output = super(PageNumberPaginator, self).page()
output['page_number'] = int(self.offset / self.limit) + 1
return output
Another common request is to alter the structure Tastypie uses in the list view. Here’s an example of renaming:
from tastypie.paginator import Paginator
class BlogEntryPaginator(Paginator):
def page(self):
output = super(BlogEntryPaginator, self).page()
# First keep a reference.
output['pagination'] = output['meta']
output['entries'] = output['objects']
# Now nuke the original keys.
del output['meta']
del output['objects']
return output
Estimated count instead of total count¶
Here’s an example, of how you can omit total_count from the resource, and instead add an estimated_count for efficiency. See the warning above for details:
import json
from django.db import connection
from tastypie.paginator import Paginator
class EstimatedCountPaginator(Paginator):
def get_next(self, limit, offset, count):
# The parent method needs an int which is higher than "limit + offset"
# to return a url. Setting it to an unreasonably large value, so that
# the parent method will always return the url.
count = 2 ** 64
return super(NoTotalCountPaginator, self).get_next(limit, offset, count)
def get_count(self):
return None
def get_estimated_count(self):
"""Get the estimated count by using the database query planner."""
# If you do not have PostgreSQL as your DB backend, alter this method
# accordingly.
return self._get_postgres_estimated_count()
def _get_postgres_estimated_count(self):
# This method only works with postgres >= 9.0.
# If you need postgres vesrions less than 9.0, remove "(format json)"
# below and parse the text explain output.
def _get_postgres_version():
# Due to django connections being lazy, we need a cursor to make
# sure the connection.connection attribute is not None.
connection.cursor()
return connection.connection.server_version
try:
if _get_postgres_version() < 90000:
return
except AttributeError:
return
cursor = connection.cursor()
query = self.objects.all().query
# Remove limit and offset from the query, and extract sql and params.
query.low_mark = None
query.high_mark = None
query, params = self.objects.query.sql_with_params()
# Fetch the estimated rowcount from EXPLAIN json output.
query = 'explain (format json) %s' % query
cursor.execute(query, params)
explain = cursor.fetchone()[0]
# Older psycopg2 versions do not convert json automatically.
if isinstance(explain, basestring):
explain = json.loads(explain)
rows = explain[0]['Plan']['Plan Rows']
return rows
def page(self):
data = super(NoTotalCountPaginator, self).page()
data['meta']['estimated_count'] = self.get_estimated_count()
return data
GeoDjango¶
Tastypie features support for GeoDjango! Resources return and accept GeoJSON (or similarly-formatted analogs for other formats) and all spatial lookup filters are supported. Distance lookups are not yet supported.
Usage¶
Here’s an example geographic model for leaving notes in polygonal regions:
from django.contrib.gis import models
class GeoNote(models.Model):
content = models.TextField()
polys = models.MultiPolygonField(null=True, blank=True)
objects = models.GeoManager()
To define a resource that takes advantage of the geospatial features, we use tastypie.contrib.gis.resources.ModelResource:
from tastypie.contrib.gis.resources import ModelResource
class GeoNoteResource(ModelResource):
class Meta:
resource_name = 'geonotes'
queryset = GeoNote.objects.all()
filtering = {
'polys': ALL,
}
Now when we do a GET on our GeoNoteResource we get back GeoJSON in our response:
{
"content": "My note content",
"id": "1",
"polys": {
"coordinates": [[[
[-122.511067, 37.771276], [-122.510037, 37.766390999999999],
[-122.510037, 37.763812999999999], [-122.456822, 37.765847999999998],
[-122.45296, 37.766458999999998], [-122.454848, 37.773989999999998],
[-122.475362, 37.773040000000002], [-122.511067, 37.771276]
]]],
"type": "MultiPolygon"
},
"resource_uri": "/api/v1/geonotes/1/"
}
When updating or creating new resources, simply provide GeoJSON or the GeoJSON analog for your perferred format.
Filtering¶
We can filter using any standard GeoDjango spatial lookup filter. Simply provide a GeoJSON (or the analog) as a GET parameter value.
Let’s find all of our GeoNote resources that contain a point inside of Golden Gate Park:
/api/v1/geonotes/?polys__contains={"type": "Point", "coordinates": [-122.475233, 37.768617]}
Returns:
{
"meta": {
"limit": 20, "next": null, "offset": 0, "previous": null, "total_count": 1},
"objects": [
{
"content": "My note content",
"id": "1",
"polys": {
"coordinates": [[[
[-122.511067, 37.771276], [-122.510037, 37.766390999999999],
[-122.510037, 37.763812999999999], [-122.456822, 37.765847999999998],
[-122.45296, 37.766458999999998], [-122.454848, 37.773989999999998],
[-122.475362, 37.773040000000002], [-122.511067, 37.771276]
]]],
"type": "MultiPolygon"
},
"resource_uri": "/api/geonotes/1/"
}
]
}
We get back the GeoNote resource defining Golden Gate Park. Awesome!
ContentTypes and GenericForeignKeys¶
Content Types and GenericForeignKeys are for relationships where the model on one end is not defined by the model’s schema.
If you’re using GenericForeignKeys in django, you can use a GenericForeignKeyField in Tastypie.
Usage¶
Here’s an example model with a GenericForeignKey taken from the Django docs:
from django.db import models
from django.contrib.contenttypes.models import ContentType
from django.contrib.contenttypes import generic
class TaggedItem(models.Model):
tag = models.SlugField()
content_type = models.ForeignKey(ContentType)
object_id = models.PositiveIntegerField()
content_object = generic.GenericForeignKey('content_type', 'object_id')
def __unicode__(self):
return self.tag
A simple ModelResource for this model might look like this:
from tastypie.contrib.contenttypes.fields import GenericForeignKeyField
from tastypie.resources import ModelResource
from .models import Note, Quote, TaggedItem
class QuoteResource(ModelResource):
class Meta:
resource_name = 'quotes'
queryset = Quote.objects.all()
class NoteResource(ModelResource):
class Meta:
resource_name = 'notes'
queryset = Note.objects.all()
class TaggedItemResource(ModelResource):
content_object = GenericForeignKeyField({
Note: NoteResource,
Quote: QuoteResource
}, 'content_object')
class Meta:
resource_name = 'tagged_items'
queryset = TaggedItem.objects.all()
Like ToOneField, you must add your GenericForeignKey attribute to your ModelResource definition. It will not be added automatically like most other field or attribute types. When you define it, you must also define the other models and match them to their resources in a dictionary, and pass that as the first argument, the second argument is the name of the attribute on the model that holds the GenericForeignKey.
Tastypie Cookbook¶
Creating a Full OAuth 2.0 API¶
It is common to use django to provision OAuth 2.0 tokens for users and then have Tasty Pie use these tokens to authenticate users to the API. Follow this tutorial and use this custom authentication class to enable OAuth 2.0 authentication with Tasty Pie.:
# api.py
from tastypie.resources import ModelResource
from tastypie.authorization import DjangoAuthorization
from polls.models import Poll, Choice
from tastypie import fields
from authentication import OAuth20Authentication
class ChoiceResource(ModelResource):
class Meta:
queryset = Choice.objects.all()
resource_name = 'choice'
authorization = DjangoAuthorization()
authentication = OAuth20Authentication()
class PollResource(ModelResource):
choices = fields.ToManyField(ChoiceResource, 'choice_set', full=True)
class Meta:
queryset = Poll.objects.all()
resource_name = 'poll'
authorization = DjangoAuthorization()
authentication = OAuth20Authentication()
Adding Custom Values¶
You might encounter cases where you wish to include additional data in a response which is not obtained from a field or method on your model. You can easily extend the dehydrate() method to provide additional values:
class MyModelResource(Resource):
class Meta:
qs = MyModel.objects.all()
def dehydrate(self, bundle):
bundle.data['custom_field'] = "Whatever you want"
return bundle
Per-Request Alterations To The Queryset¶
A common pattern is needing to limit a queryset by something that changes per-request, for instance the date/time. You can accomplish this by lightly modifying get_object_list:
from tastypie.utils import now
class MyResource(ModelResource):
class Meta:
queryset = MyObject.objects.all()
def get_object_list(self, request):
return super(MyResource, self).get_object_list(request).filter(start_date__gte=now)
Using Your Resource In Regular Views¶
In addition to using your resource classes to power the API, you can also use them to write other parts of your application, such as your views. For instance, if you wanted to encode user information in the page for some Javascript’s use, you could do the following:
# views.py
from django.shortcuts import render_to_response
from myapp.api.resources import UserResource
def user_detail(request, username):
ur = UserResource()
user = ur.obj_get(username=username)
# Other things get prepped to go into the context then...
ur_bundle = ur.build_bundle(obj=user, request=request)
return render_to_response('myapp/user_detail.html', {
# Other things here.
"user_json": ur.serialize(None, ur.full_dehydrate(ur_bundle), 'application/json'),
})
Example of getting a list of users:
def user_list(request):
res = UserResource()
request_bundle = res.build_bundle(request=request)
queryset = res.obj_get_list(request_bundle)
bundles = []
for obj in queryset:
bundle = res.build_bundle(obj=obj, request=request)
bundles.append(res.full_dehydrate(bundle, for_list=True))
list_json = res.serialize(None, bundles, "application/json")
return render_to_response('myapp/user_list.html', {
# Other things here.
"list_json": list_json,
})
Then in template you could convert JSON into JavaScript object:
<script>
var json = "{{list_json|escapejs}}";
var users = JSON.parse(json);
</script>
Using Non-PK Data For Your URLs¶
By convention, ModelResources usually expose the detail endpoints utilizing the primary key of the Model they represent. However, this is not a strict requirement. Each URL can take other named URLconf parameters that can be used for the lookup.
For example, if you want to expose User resources by username, you can do something like the following:
# myapp/api/resources.py
class UserResource(ModelResource):
class Meta:
queryset = User.objects.all()
detail_uri_name = 'username'
def prepend_urls(self):
return [
url(r"^(?P<resource_name>%s)/(?P<username>[\w\d_.-]+)/$" % self._meta.resource_name, self.wrap_view('dispatch_detail'), name="api_dispatch_detail"),
]
The added URLconf matches before the standard URLconf included by default & matches on the username provided in the URL.
Nested Resources¶
You can also do “nested resources” (resources within another related resource) by lightly overriding the prepend_urls method & adding on a new method to handle the children:
class ParentResource(ModelResource):
children = fields.ToManyField(ChildResource, 'children')
def prepend_urls(self):
return [
url(r"^(?P<resource_name>%s)/(?P<pk>\w[\w/-]*)/children%s$" % (self._meta.resource_name, trailing_slash()), self.wrap_view('get_children'), name="api_get_children"),
]
def get_children(self, request, **kwargs):
try:
bundle = self.build_bundle(data={'pk': kwargs['pk']}, request=request)
obj = self.cached_obj_get(bundle=bundle, **self.remove_api_resource_names(kwargs))
except ObjectDoesNotExist:
return HttpGone()
except MultipleObjectsReturned:
return HttpMultipleChoices("More than one resource is found at this URI.")
child_resource = ChildResource()
return child_resource.get_detail(request, parent_id=obj.pk)
Another alternative approach is to override the dispatch method:
# myapp/api/resources.py
class EntryResource(ModelResource):
user = fields.ForeignKey(UserResource, 'user')
class Meta:
queryset = Entry.objects.all()
resource_name = 'entry'
def dispatch(self, request_type, request, **kwargs):
username = kwargs.pop('username')
kwargs['user'] = get_object_or_404(User, username=username)
return super(EntryResource, self).dispatch(request_type, request, **kwargs)
# urls.py
from django.conf.urls.defaults import *
from myapp.api import EntryResource
entry_resource = EntryResource()
urlpatterns = patterns('',
# The normal jazz here, then...
(r'^api/(?P<username>\w+)/', include(entry_resource.urls)),
)
Adding Search Functionality¶
Another common request is being able to integrate search functionality. This approach uses Haystack, though you could hook it up to any search technology. We leave the CRUD methods of the resource alone, choosing to add a new endpoint at /api/v1/notes/search/:
from django.conf.urls.defaults import *
from django.core.paginator import Paginator, InvalidPage
from django.http import Http404
from haystack.query import SearchQuerySet
from tastypie.resources import ModelResource
from tastypie.utils import trailing_slash
from notes.models import Note
class NoteResource(ModelResource):
class Meta:
queryset = Note.objects.all()
resource_name = 'notes'
def prepend_urls(self):
return [
url(r"^(?P<resource_name>%s)/search%s$" % (self._meta.resource_name, trailing_slash()), self.wrap_view('get_search'), name="api_get_search"),
]
def get_search(self, request, **kwargs):
self.method_check(request, allowed=['get'])
self.is_authenticated(request)
self.throttle_check(request)
# Do the query.
sqs = SearchQuerySet().models(Note).load_all().auto_query(request.GET.get('q', ''))
paginator = Paginator(sqs, 20)
try:
page = paginator.page(int(request.GET.get('page', 1)))
except InvalidPage:
raise Http404("Sorry, no results on that page.")
objects = []
for result in page.object_list:
bundle = self.build_bundle(obj=result.object, request=request)
bundle = self.full_dehydrate(bundle)
objects.append(bundle)
object_list = {
'objects': objects,
}
self.log_throttled_access(request)
return self.create_response(request, object_list)
Creating per-user resources¶
One might want to create an API which will require every user to authenticate and every user will be working only with objects associated with them. Let’s see how to implement it for two basic operations: listing and creation of an object.
For listing we want to list only objects for which ‘user’ field matches ‘request.user’. This could be done by applying a filter in the apply_authorization_limits method of your resource.
For creating we’d have to wrap obj_create method of ModelResource. Then the resulting code will look something like:
# myapp/api/resources.py
class EnvironmentResource(ModelResource):
class Meta:
queryset = Environment.objects.all()
resource_name = 'environment'
list_allowed_methods = ['get', 'post']
authentication = ApiKeyAuthentication()
authorization = Authorization()
def obj_create(self, bundle, **kwargs):
return super(EnvironmentResource, self).obj_create(bundle, user=bundle.request.user)
def apply_authorization_limits(self, request, object_list):
return object_list.filter(user=request.user)
camelCase JSON Serialization¶
The convention in the world of Javascript has standardized on camelCase, where Tastypie uses underscore syntax, which can lead to “ugly” looking code in Javascript. You can create a custom serializer that emits values in camelCase instead:
from tastypie.serializers import Serializer
import re
import json
class CamelCaseJSONSerializer(Serializer):
formats = ['json']
content_types = {
'json': 'application/json',
}
def to_json(self, data, options=None):
# Changes underscore_separated names to camelCase names to go from python convention to javacsript convention
data = self.to_simple(data, options)
def underscoreToCamel(match):
return match.group()[0] + match.group()[2].upper()
def camelize(data):
if isinstance(data, dict):
new_dict = {}
for key, value in data.items():
new_key = re.sub(r"[a-z]_[a-z]", underscoreToCamel, key)
new_dict[new_key] = camelize(value)
return new_dict
if isinstance(data, (list, tuple)):
for i in range(len(data)):
data[i] = camelize(data[i])
return data
return data
camelized_data = camelize(data)
return json.dumps(camelized_data, sort_keys=True)
def from_json(self, content):
# Changes camelCase names to underscore_separated names to go from javascript convention to python convention
data = json.loads(content)
def camelToUnderscore(match):
return match.group()[0] + "_" + match.group()[1].lower()
def underscorize(data):
if isinstance(data, dict):
new_dict = {}
for key, value in data.items():
new_key = re.sub(r"[a-z][A-Z]", camelToUnderscore, key)
new_dict[new_key] = underscorize(value)
return new_dict
if isinstance(data, (list, tuple)):
for i in range(len(data)):
data[i] = underscorize(data[i])
return data
return data
underscored_data = underscorize(data)
return underscored_data
Pretty-printed JSON Serialization¶
By default, Tastypie outputs JSON with no indentation or newlines (equivalent to calling json.dumps() with indent set to None). You can override this behavior in a custom serializer:
import json as simplejson
from django.core.serializers import json
from tastypie.serializers import Serializer
class PrettyJSONSerializer(Serializer):
json_indent = 2
def to_json(self, data, options=None):
options = options or {}
data = self.to_simple(data, options)
return simplejson.dumps(data, cls=json.DjangoJSONEncoder,
sort_keys=True, ensure_ascii=False, indent=self.json_indent)
Determining format via URL¶
Sometimes it’s required to allow selecting the response format by specifying it in the API URL, for example /api/v1/users.json instead of /api/v1/users/?format=json. The following snippet allows that kind of syntax additional to the default URL scheme:
# myapp/api/resources.py
# Piggy-back on internal csrf_exempt existence handling
from tastypie.resources import csrf_exempt
class UserResource(ModelResource):
class Meta:
queryset = User.objects.all()
def prepend_urls(self):
"""
Returns a URL scheme based on the default scheme to specify
the response format as a file extension, e.g. /api/v1/users.json
"""
return [
url(r"^(?P<resource_name>%s)\.(?P<format>\w+)$" % self._meta.resource_name, self.wrap_view('dispatch_list'), name="api_dispatch_list"),
url(r"^(?P<resource_name>%s)/schema\.(?P<format>\w+)$" % self._meta.resource_name, self.wrap_view('get_schema'), name="api_get_schema"),
url(r"^(?P<resource_name>%s)/set/(?P<pk_list>\w[\w/;-]*)\.(?P<format>\w+)$" % self._meta.resource_name, self.wrap_view('get_multiple'), name="api_get_multiple"),
url(r"^(?P<resource_name>%s)/(?P<pk>\w[\w/-]*)\.(?P<format>\w+)$" % self._meta.resource_name, self.wrap_view('dispatch_detail'), name="api_dispatch_detail"),
]
def determine_format(self, request):
"""
Used to determine the desired format from the request.format
attribute.
"""
if (hasattr(request, 'format') and
request.format in self._meta.serializer.formats):
return self._meta.serializer.get_mime_for_format(request.format)
return super(UserResource, self).determine_format(request)
def wrap_view(self, view):
@csrf_exempt
def wrapper(request, *args, **kwargs):
request.format = kwargs.pop('format', None)
wrapped_view = super(UserResource, self).wrap_view(view)
return wrapped_view(request, *args, **kwargs)
return wrapper
Adding to the Django Admin¶
If you’re using the django admin and ApiKeyAuthentication, you may want to see or edit ApiKeys next to users. To do this, you need to unregister the built-in UserAdmin, alter the inlines, and re-register it. This could go in any of your admin.py files. You may also want to register ApiAccess and ApiKey models on their own.:
from tastypie.admin import ApiKeyInline
from tastypie.models import ApiAccess, ApiKey
from django.contrib.auth.admin import UserAdmin
from django.contrib.auth.models import User
admin.site.register(ApiKey)
admin.site.register(ApiAccess)
class UserModelAdmin(UserAdmin):
inlines = UserAdmin.inlines + [ApiKeyInline]
admin.site.unregister(User)
admin.site.register(User,UserModelAdmin)
Using SessionAuthentication¶
If your users are logged into the site & you want Javascript to be able to access the API (assuming jQuery), the first thing to do is setup SessionAuthentication:
from django.contrib.auth.models import User
from tastypie.authentication import SessionAuthentication
from tastypie.resources import ModelResource
class UserResource(ModelResource):
class Meta:
resource_name = 'users'
queryset = User.objects.all()
authentication = SessionAuthentication()
Then you’d build a template like:
<html>
<head>
<title></title>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.7.2/jquery.min.js"></script>
<script type="text/javascript">
$(document).ready(function() {
// We use ``.ajax`` here due to the overrides.
$.ajax({
// Substitute in your API endpoint here.
url: '/api/v1/users/',
contentType: 'application/json',
// The ``X-CSRFToken`` evidently can't be set in the
// ``headers`` option, so force it here.
// This method requires jQuery 1.5+.
beforeSend: function(jqXHR, settings) {
// Pull the token out of the DOM.
jqXHR.setRequestHeader('X-CSRFToken', $('input[name=csrfmiddlewaretoken]').val());
},
success: function(data, textStatus, jqXHR) {
// Your processing of the data here.
console.log(data);
}
});
});
</script>
</head>
<body>
<!-- Include the CSRF token in the body of the HTML -->
{% csrf_token %}
</body>
</html>
There are other ways to make this function, with other libraries or other techniques for supplying the token (see https://docs.djangoproject.com/en/dev/ref/contrib/csrf/#ajax for an alternative). This is simply a starting point for getting things working.
Debugging Tastypie¶
There are some common problems people run into when using Tastypie for the first time. Some of the common problems and things to try appear below.
“I’m getting XML output in my browser but I want JSON output!”¶
This is actually not a bug and JSON support is present in your Resource. This issue is that Tastypie respects the Accept header your browser sends. Most browsers send something like:
Accept: application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,image/png,*/*;q=0.5
Note that application/xml comes first, which is a format that Tastypie handles by default, hence why you receive XML.
If you use curl from the command line, you should receive JSON by default:
curl http://localhost:8000/api/v1/
If you want JSON in the browser, simply append ?format=json to your URL. Tastypie always respects this override first, before it falls back to the Accept header.
“What’s the format for a POST or PUT?”¶
You can view full schema for your resource through Inspecting The Resource’s Schema.
In general, Tastypie will accept resources in the same format as it gives you. This means that you can see what any POST or PUT should look like by performing a GET of that resource.
Creating a duplicate of an entry, using Python and Requests:
import requests
import json
response = requests.get('http://localhost:8000/api/v1/entry/1/')
event = json.loads(response.content)
del event['id'] # We want the server to assign a new id
response = requests.post('http://localhost:8000/api/v1/entry/',
data=json.dumps(event),
headers={'content-type': 'application/json'})
The new event should be almost identical, with the exception of readonly fields. This method may fail if your model has a unique constraint, or otherwise fails validation.
This is less likely to happen on PUT, except for application logic changes (e.g. a last_update field). The following two curl commands replace and entry with an copy:
curl -H 'Accept: application/json' 'http://localhost:8000/api/v1/entry/1/' | \
curl -H 'Content-Type: application/json' -X PUT --data @- "http://localhost:8000/api/v1/entry/1/"
You can do this over an entire collection as well:
curl -H 'Accept: application/json' 'http://localhost:8000/api/v1/entry/?limit=0' | \
curl -H 'Content-Type: application/json' -X PUT --data @- "http://localhost:8000/api/v1/entry/"
“Why is my syncdb with superuser failing with a DatabaseError?”¶
More specifically, this specific DatabaseError:
django.db.utils.DatabaseError: no such table: tastypie_apikey
This is a side effect of the (disabled by default) create_api_key signal as described in the Authentication section of the documentation when used in conjunction with South.
To work around this issue, you can disable the create_api_key signal until you have completed running syncdb --migrate for the first time.
Sites Using Tastypie¶
The following sites are a partial list of people using Tastypie. I’m always interested in adding more sites, so please find me (daniellindsley) via IRC or start a mailing list thread.
LJWorld Marketplace¶
Forkinit¶
Read-only API access to recipes.
Read The Docs¶
A hosted documentation site, primarily for Python docs. General purpose read-write access.
Luzme¶
An e-book search site that lets you fetch pricing information.
Politifact¶
To power their mobile (iPhone/Android/Playbook) applications.
LocalWiki¶
LocalWiki is a tool for collaborating in local, geographic communities. It’s using Tastypie to provide an geospatially-aware REST API.
I-Am-CC.org¶
I-Am-CC.org is a tool for releasing Instagram photos under a Creative Commons license.
Dbpatterns¶
Dbpatterns is a service that allows you to create, share, explore database models on the web.
Contributing¶
Tastypie is open-source and, as such, grows (or shrinks) & improves in part due to the community. Below are some guidelines on how to help with the project.
Philosophy¶
- Tastypie is BSD-licensed. All contributed code must be either
- the original work of the author, contributed under the BSD, or...
- work taken from another project released under a BSD-compatible license.
- GPL’d (or similar) works are not eligible for inclusion.
- Tastypie’s git master branch should always be stable, production-ready & passing all tests.
- Major releases (1.x.x) are commitments to backward-compatibility of the public APIs. Any documented API should ideally not change between major releases. The exclusion to this rule is in the event of either a security issue or to accommodate changes in Django itself.
- Minor releases (x.3.x) are for the addition of substantial features or major bugfixes.
- Patch releases (x.x.4) are for minor features or bugfixes.
Guidelines For Reporting An Issue/Feature¶
So you’ve found a bug or have a great idea for a feature. Here’s the steps you should take to help get it added/fixed in Tastypie:
- First, check to see if there’s an existing issue/pull request for the bug/feature. All issues are at https://github.com/toastdriven/django-tastypie/issues and pull reqs are at https://github.com/toastdriven/django-tastypie/pulls.
- If there isn’t one there, please file an issue. The ideal report includes:
- A description of the problem/suggestion.
- How to recreate the bug.
- If relevant, including the versions of your:
- Python interpreter
- Django
- Tastypie
- Optionally of the other dependencies involved
- Ideally, creating a pull request with a (failing) test case demonstrating what’s wrong. This makes it easy for us to reproduce & fix the problem. Instructions for running the tests are at Welcome to Tastypie!
You might also hop into the IRC channel (#tastypie on irc.freenode.net) & raise your question there, as there may be someone who can help you with a work-around.
Guidelines For Contributing Code¶
If you’re ready to take the plunge & contribute back some code/docs, the process should look like:
- Fork the project on GitHub into your own account.
- Clone your copy of Tastypie.
- Make a new branch in git & commit your changes there.
- Push your new branch up to GitHub.
- Again, ensure there isn’t already an issue or pull request out there on it. If there is & you feel you have a better fix, please take note of the issue number & mention it in your pull request.
- Create a new pull request (based on your branch), including what the problem/feature is, versions of your software & referencing any related issues/pull requests.
In order to be merged into Tastypie, contributions must have the following:
- A solid patch that:
- is clear.
- works across all supported versions of Python/Django.
- follows the existing style of the code base (mostly PEP-8).
- comments included as needed.
- A test case that demonstrates the previous flaw that now passes with the included patch.
- If it adds/changes a public API, it must also include documentation for those changes.
- Must be appropriately licensed (see “Philosophy”).
- Adds yourself to the AUTHORS file.
If your contribution lacks any of these things, they will have to be added by a core contributor before being merged into Tastypie proper, which may take substantial time for the all-volunteer team to get to.
Guidelines For Core Contributors¶
If you’ve been granted the commit bit, here’s how to shepherd the changes in:
Any time you go to work on Tastypie, please use git pull --rebase to fetch the latest changes.
Any new features/bug fixes must meet the above guidelines for contributing code (solid patch/tests passing/docs included).
Commits are typically cherry-picked onto a branch off master.
- This is done so as not to include extraneous commits, as some people submit pull reqs based on their git master that has other things applied to it.
A set of commits should be squashed down to a single commit.
- git merge --squash is a good tool for performing this, as is git rebase -i HEAD~N.
- This is done to prevent anyone using the git repo from accidently pulling work-in-progress commits.
Commit messages should use past tense, describe what changed & thank anyone involved. Examples:
"""Added a new way to do per-object authorization.""" """Fixed a bug in ``Serializer.to_xml``. Thanks to joeschmoe for the report!""" """BACKWARD-INCOMPATIBLE: Altered the arguments passed to ``Bundle.__init__``. Further description appears here if the change warrants an explanation as to why it was done."""
For any patches applied from a contributor, please ensure their name appears in the AUTHORS file.
When closing issues or pull requests, please reference the SHA in the closing message (i.e. Thanks! Fixed in SHA: 6b93f6). GitHub will automatically link to it.
Release Notes¶
v0.9.13¶
SECURITY HARDENING
The latest version of Tastypie includes a number of important security fixes and all users are strongly encouraged to upgrade.
Please note that the fixes might cause backwards incompatibility issues, so please check the upgrade notes carefully.
Security hardening improvements¶
XML decoding has been wrapped in the defusedxml library
XML requests may no longer include DTDs by default
Deserialization will return HTTP 400 for any XML decode errors
Don’t even use XML and want to disable it? There’s a simple TASTYPIE_DEFAULT_FORMATS setting setting to globally restrict the set of supported formats (closes #833):
http://django-tastypie.readthedocs.org/en/v0.9.14/settings.html#tastypie-default-formats
Content negotiation will return an error for malformed accept headers (closes #832)
The Api class itself now allows a custom serializer (closes #817)
The serialization documentation has been upgraded with security advice:
Upgrade notes:
- If you use XML serialization (enabled by default):
- defusedxml is now required
- defusedxml requires lxml 3 or later
pip install defusedxml "lxml>=3"
Python 2.5 is no longer officially supported because defusedxml requires Python 2.6 or later. If you cannot upgrade to a newer version of Python please consider disabling XML support entirely.
v0.9.14¶
date: | 2013-03-19 |
---|
An emergency release removing a failed attempt at using rose to handle versioning.
Features¶
- None
Bugfixes¶
- Removed the dependency on rose, which wasn’t effective at de-duplicating the version information. :(
v0.9.15¶
date: | 2013-05-02 |
---|
This release is primarily a bugfix release. It makes using Tastypie with Django 1.5 more friendly, better exceptions
Features¶
- Drops Python 2.5 support. Yes, this is a feature that will pave the way for Tastypie on Python 3 support.
- Added TASTYPIE_ABSTRACT_APIKEY, which allows switching the ApiKey model out. (SHA: b8f4b9c)
Bugfixes¶
Better support for Django 1.5:
- Removed deprecation warnings (SHA: bb01761)
- Numerous custom User improvements (SHA: d24b390)
Expanded places use_in is used (SHA: b32c45)
Authorization is now only called once with a full bundle (SHA: f06f41)
Changed for_list to accept a boolean (SHA: 01e620)
Only save related models that have changed (SHA: 6efdea)
Better exception reporting, especially in conjunction with Sentry
- (SHA: 3f9ce0)
- (SHA: 4adf11)
Configuration warning about defusedxml (SHA: aa8d9fd)
Fixed a dependency in setup.py (SHA: cb0fe7)
Release notes became a thing! Hooray! (SHA: 95e2499)
Documentation updates:
- Typo in CleanedDataFormValidation (SHA: bf252a)
- CamelCase JSON (SHA: bf252a)
- Docstring typo (SHA: e86dad)
- Per-user resource (SHA: a77b28c)
- Added more details about creating the ApiKey model (SHA: 80f9b8)
Getting Help¶
There are two primary ways of getting help. We have a mailing list hosted at Google (http://groups.google.com/group/django-tastypie/) and an IRC channel (#tastypie on irc.freenode.net) to get help, want to bounce idea or generally shoot the breeze.
Quick Start¶
Add tastypie to INSTALLED_APPS.
Create an api directory in your app with a bare __init__.py.
Create an <my_app>/api/resources.py file and place the following in it:
from tastypie.resources import ModelResource from my_app.models import MyModel class MyModelResource(ModelResource): class Meta: queryset = MyModel.objects.all() allowed_methods = ['get']
In your root URLconf, add the following code (around where the admin code might be):
from tastypie.api import Api from my_app.api.resources import MyModelResource v1_api = Api(api_name='v1') v1_api.register(MyModelResource()) urlpatterns = patterns('', # ...more URLconf bits here... # Then add: (r'^api/', include(v1_api.urls)), )
Hit http://localhost:8000/api/v1/?format=json in your browser!
Requirements¶
Tastypie requires the following modules. If you use Pip, you can install the necessary bits via the included requirements.txt:
Required¶
- Python 2.6+
- Django 1.3+
- mimeparse 0.1.3+ (http://code.google.com/p/mimeparse/)
- Older versions will work, but their behavior on JSON/JSONP is a touch wonky.
- dateutil (http://labix.org/python-dateutil) >= 1.5, < 2.0
Optional¶
- python_digest (https://bitbucket.org/akoha/python-digest/)
- lxml (http://lxml.de/) and defusedxml (https://bitbucket.org/tiran/defusedxml) if using the XML serializer
- pyyaml (http://pyyaml.org/) if using the YAML serializer
- biplist (http://explorapp.com/biplist/) if using the binary plist serializer
Why Tastypie?¶
There are other, better known API frameworks out there for Django. You need to assess the options available and decide for yourself. That said, here are some common reasons for tastypie.
- You need an API that is RESTful and uses HTTP well.
- You want to support deep relations.
- You DON’T want to have to write your own serializer to make the output right.
- You want an API framework that has little magic, very flexible and maps well to the problem domain.
- You want/need XML serialization that is treated equally to JSON (and YAML is there too).
- You want to support my perceived NIH syndrome, which is less about NIH and more about trying to help out friends/coworkers.
Reference Material¶
Running The Tests¶
The easiest way to get setup to run Tastypie’s tests looks like:
$ git clone https://github.com/toastdriven/django-tastypie.git
$ cd django-tastypie
$ virtualenv env
$ . env/bin/activate
$ ./env/bin/pip install -U -r requirements.txt
Then running the tests is as simple as:
# From the same directory as above:
$ ./env/bin/pip install -U -r tests/requirements.txt
$ cd tests
$ ./run_all_test.sh
Tastypie is maintained with all tests passing at all times. If you find a failure, please report it along with the versions of the installed software.
Commercial Support¶
If you’re using Tastypie in a commercial environment, paid support is available from Toast Driven. Services offered include:
- Advice/help with setup
- Implementation in your project
- Bugfixes in Tastypie itself
- Features in Tastypie itself
If you’re interested, please contact Daniel Lindsley (daniel@toastdriven.com).
Getting Started with Tastypie¶
Tastypie is a reusable app (that is, it relies only on it’s own code and focuses on providing just a REST-style API) and is suitable for providing an API to any application without having to modify the sources of that app.
Not everyone’s needs are the same, so Tastypie goes out of its way to provide plenty of hooks for overriding or extending how it works.
Note
If you hit a stumbling block, you can join #tastypie on irc.freenode.net to get help.
This tutorial assumes that you have a basic understanding of Django as well as how proper REST-style APIs ought to work. We will only explain the portions of the code that are Tastypie-specific in any kind of depth.
For example purposes, we’ll be adding an API to a simple blog application. Here is myapp/models.py:
from tastypie.utils.timezone import now
from django.contrib.auth.models import User
from django.db import models
from django.template.defaultfilters import slugify
class Entry(models.Model):
user = models.ForeignKey(User)
pub_date = models.DateTimeField(default=now)
title = models.CharField(max_length=200)
slug = models.SlugField()
body = models.TextField()
def __unicode__(self):
return self.title
def save(self, *args, **kwargs):
# For automatic slug generation.
if not self.slug:
self.slug = slugify(self.title)[:50]
return super(Entry, self).save(*args, **kwargs)
With that, we’ll move on to installing and configuring Tastypie.
Installation¶
Installing Tastypie is as simple as checking out the source and adding it to your project or PYTHONPATH.
- Download the dependencies:
- Python 2.4+
- Django 1.0+ (tested on Django 1.1+)
- mimeparse 0.1.3+ (http://code.google.com/p/mimeparse/)
- Older versions will work, but their behavior on JSON/JSONP is a touch wonky.
- dateutil (http://labix.org/python-dateutil)
- OPTIONAL - lxml (http://lxml.de/) if using the XML serializer
- OPTIONAL - pyyaml (http://pyyaml.org/) if using the YAML serializer
- OPTIONAL - uuid (present in 2.5+, downloadable from http://pypi.python.org/pypi/uuid/) if using the ApiKey authentication
Note
Once tastypie reaches version 1.0, it will become officially available on PyPI. Once that is the case, a sudo pip install tastypie or sudo easy_install tastypie should be available.
Configuration¶
The only mandatory configuration is adding 'tastypie' to your INSTALLED_APPS. This isn’t strictly necessary, as Tastypie has only two non-required models, but may ease usage.
You have the option to set up a number of settings (see Tastypie Settings) but they all have sane defaults and are not required unless you need to tweak their values.
Creating Resources¶
REST-style architecture talks about resources, so unsurprisingly integrating with Tastypie involves creating Resource classes. For our simple application, we’ll create a file for these in myapp/api.py, though they can live anywhere in your application:
# myapp/api.py
from tastypie.resources import ModelResource
from myapp.models import Entry
class EntryResource(ModelResource):
class Meta:
queryset = Entry.objects.all()
resource_name = 'entry'
This class, by virtue of being a ModelResource subclass, will introspect all non-relational fields on the Entry model and create it’s own ApiFields that map to those fields, much like the way Django’s ModelForm class introspects.
Note
The resource_name within the Meta class is optional. If not provided, it is automatically generated off the classname, removing any instances of Resource and lowercasing the string. So EntryResource would become just entry.
We’ve included the resource_name attribute in this example for clarity, especially when looking at the URLs, but you should feel free to omit it if you’re comfortable with the automatic behavior.
Hooking Up The Resource(s)¶
Now that we have our EntryResource, we can hook it up in our URLconf. To do this, we simply instantiate the resource in our URLconf and hook up its urls:
# urls.py
from django.conf.urls.defaults import *
from myapp.api import EntryResource
entry_resource = EntryResource()
urlpatterns = patterns('',
# The normal jazz here...
(r'^blog/', include('myapp.urls')),
(r'^api/', include(entry_resource.urls)),
)
Now it’s just a matter of firing up server (./manage.py runserver) and going to http://127.0.0.1:8000/api/entry/?format=json. You should get back a list of Entry-like objects.
Note
The ?format=json is an override required to make things look decent in the browser (accept headers vary between browsers). Tastypie properly handles the Accept header. So the following will work properly:
curl -H "Accept: application/json" http://127.0.0.1:8000/api/entry/
But if you’re sure you want something else (or want to test in a browser), Tastypie lets you specify ?format=... when you really want to force a certain type.
At this point, a bunch of other URLs are also available. Try out any/all of the following (assuming you have at least three records in the database):
However, if you try sending a POST/PUT/DELETE to the resource, you find yourself getting “401 Unauthorized” errors. For safety, Tastypie ships with the authorization class (“what are you allowed to do”) set to ReadOnlyAuthorization. This makes it safe to expose on the web, but prevents us from doing POST/PUT/DELETE. Let’s enable those:
# myapp/api.py
from tastypie.authorization import Authorization
from tastypie.resources import ModelResource
from myapp.models import Entry
class EntryResource(ModelResource):
class Meta:
queryset = Entry.objects.all()
resource_name = 'entry'
authorization= Authorization()
Warning
This is now great for testing in development but VERY INSECURE. You should never put a Resource like this out on the internet. Please spend some time looking at the authentication/authorization classes available in Tastypie.
With just nine lines of code, we have a full working REST interface to our Entry model. In addition, full GET/POST/PUT/DELETE support is already there, so it’s possible to really work with all of the data. Well, almost.
You see, you’ll note that not quite all of our data is there. Markedly absent is the user field, which is a ForeignKey to Django’s User model. Tastypie does NOT introspect related data because it has no way to know how you want to represent that data.
And since that relation isn’t there, any attempt to POST/PUT new data will fail, because no user is present, which is a required field on the model.
This is easy to fix, but we’ll need to flesh out our API a little more.
Creating More Resources¶
In order to handle our user relation, we’ll need to create a UserResource and tell the EntryResource to use it. So we’ll modify myapp/api.py to match the following code:
# myapp/api.py
from django.contrib.auth.models import User
from tastypie import fields
from tastypie.resources import ModelResource
from myapp.models import Entry
class UserResource(ModelResource):
class Meta:
queryset = User.objects.all()
resource_name = 'user'
class EntryResource(ModelResource):
user = fields.ForeignKey(UserResource, 'user')
class Meta:
queryset = Entry.objects.all()
resource_name = 'entry'
We simply created a new ModelResource subclass called UserResource. Then we added a field to EntryResource that specified that the user field points to a UserResource for that data.
Now we should be able to get all of the fields back in our response. But since we have another full, working resource on our hands, we should hook that up to our API as well. And there’s a better way to do it.
Adding To The Api¶
Tastypie ships with an Api class, which lets you bind multiple Resources together to form a coherent API. Adding it to the mix is simple.
We’ll go back to our URLconf (urls.py) and change it to match the following:
# urls.py
from django.conf.urls.defaults import *
from tastypie.api import Api
from myapp.api import EntryResource, UserResource
v1_api = Api(api_name='v1')
v1_api.register(UserResource())
v1_api.register(EntryResource())
urlpatterns = patterns('',
# The normal jazz here...
(r'^blog/', include('myapp.urls')),
(r'^api/', include(v1_api.urls)),
)
Note that we’re now creating an Api instance, registering our EntryResource and UserResource instances with it and that we’ve modified the urls to now point to v1_api.urls.
This makes even more data accessible, so if we start up the runserver again, the following URLs should work:
- http://127.0.0.1:8000/api/v1/?format=json
- http://127.0.0.1:8000/api/v1/user/?format=json
- http://127.0.0.1:8000/api/v1/user/1/?format=json
- http://127.0.0.1:8000/api/v1/user/schema/?format=json
- http://127.0.0.1:8000/api/v1/user/set/1;3/?format=json
- http://127.0.0.1:8000/api/v1/entry/?format=json
- http://127.0.0.1:8000/api/v1/entry/1/?format=json
- http://127.0.0.1:8000/api/v1/entry/schema/?format=json
- http://127.0.0.1:8000/api/v1/entry/set/1;3/?format=json
Additionally, the representations out of EntryResource will now include the user field and point to an endpoint like /api/v1/users/1/ to access that user’s data. And full POST/PUT delete support should now work.
But there’s several new problems. One is that our new UserResource leaks too much data, including fields like email, password, is_active and is_staff. Another is that we may not want to allow end users to alter User data. Both of these problems are easily fixed as well.
Limiting Data And Access¶
Cutting out the email, password, is_active and is_staff fields is easy to do. We simply modify our UserResource code to match the following:
class UserResource(ModelResource):
class Meta:
queryset = User.objects.all()
resource_name = 'user'
excludes = ['email', 'password', 'is_active', 'is_staff', 'is_superuser']
The excludes directive tells UserResource which fields not to include in the output. If you’d rather whitelist fields, you could do:
class UserResource(ModelResource):
class Meta:
queryset = User.objects.all()
resource_name = 'user'
fields = ['username', 'first_name', 'last_name', 'last_login']
Now that the undesirable fields are no longer included, we can look at limiting access. This is also easy and involves making our UserResource look like:
class UserResource(ModelResource):
class Meta:
queryset = User.objects.all()
resource_name = 'user'
excludes = ['email', 'password', 'is_active', 'is_staff', 'is_superuser']
allowed_methods = ['get']
Now only HTTP GET requests will be allowed on /api/v1/user/ endpoints. If you require more granular control, both list_allowed_methods and detail_allowed_methods options are supported.
Beyond The Basics¶
We now have a full working API for our application. But Tastypie supports many more features, like:
- Authentication
- Authorization
- Caching
- Throttling
- Resources (filtering & sorting)
- Serialization
Tastypie is also very easy to override and extend. For some common patterns and approaches, you should refer to the Tastypie Cookbook documentation.
Interacting With The API¶
Now that you’ve got a shiny new REST-style API in place, let’s demonstrate how to interact with it. We’ll assume that you have cURL installed on your system (generally available on most modern Mac & Linux machines), but any tool that allows you to control headers & bodies on requests will do.
We’ll assume that we’re interacting with the following Tastypie code:
# myapp/api/resources.py
from django.contrib.auth.models import User
from tastypie.authorization import Authorization
from tastypie import fields
from tastypie.resources import ModelResource, ALL, ALL_WITH_RELATIONS
from myapp.models import Entry
class UserResource(ModelResource):
class Meta:
queryset = User.objects.all()
resource_name = 'user'
excludes = ['email', 'password', 'is_active', 'is_staff', 'is_superuser']
filtering = {
'username': ALL,
}
class EntryResource(ModelResource):
user = fields.ForeignKey(UserResource, 'user')
class Meta:
queryset = Entry.objects.all()
resource_name = 'entry'
authorization = Authorization()
filtering = {
'user': ALL_WITH_RELATIONS,
'pub_date': ['exact', 'lt', 'lte', 'gte', 'gt'],
}
# urls.py
from django.conf.urls.defaults import *
from tastypie.api import Api
from myapp.api.resources import EntryResource, UserResource
v1_api = Api(api_name='v1')
v1_api.register(UserResource())
v1_api.register(EntryResource())
urlpatterns = patterns('',
# The normal jazz here...
(r'^blog/', include('myapp.urls')),
(r'^api/', include(v1_api.urls)),
)
Let’s fire up a shell & start exploring the API!
Front Matter¶
Tastypie tries to treat all clients & all serialization types as equally as possible. It also tries to be a good ‘Net citizen & respects the HTTP method used as well as the Accepts headers sent. Between these two, you control all interactions with Tastypie through relatively few endpoints.
Warning
Should you try these URLs in your browser, be warned you WILL need to append ?format=json (or xml or yaml) to the URL. Your browser requests application/xml before application/json, so you’ll always get back XML if you don’t specify it.
That’s also why it’s recommended that you explore via curl, because you avoid your browser’s opinionated requests & get something closer to what any programmatic clients will get.
Fetching Data¶
Since reading data out of an API is a very common activity (and the easiest type of request to make), we’ll start there. Tastypie tries to expose various parts of the API & interlink things within the API (HATEOAS).
Api-Wide¶
We’ll start at the highest level:
curl http://localhost:8000/api/v1/
You’ll get back something like:
{
"entry": {
"list_endpoint": "/api/v1/entry/",
"schema": "/api/v1/entry/schema/"
},
"user": {
"list_endpoint": "/api/v1/user/",
"schema": "/api/v1/user/schema/"
}
}
This lists out all the different Resource classes you registered in your URLconf with the API. Each one is listed by the resource_name you gave it and provides the list_endpoint & the schema for the resource.
Note that these links try to direct you to other parts of the API, to make exploration/discovery easier. We’ll use these URLs in the next several sections.
To demonstrate another format, you could run the following to get the XML variant of the same information:
curl -H "Accept: application/xml" http://localhost:8000/api/v1/
To which you’d receive:
<?xml version="1.0" encoding="utf-8"?>
<response>
<entry type="hash">
<list_endpoint>/api/v1/entry/</list_endpoint>
<schema>/api/v1/entry/schema/</schema>
</entry>
<user type="hash">
<list_endpoint>/api/v1/user/</list_endpoint>
<schema>/api/v1/user/schema/</schema>
</user>
</response>
We’ll stick to JSON for the rest of this document, but using XML should be OK to do at any time.
Inspecting The Resource’s Schema¶
Since the api-wide view gave us a schema URL, let’s inspect that next. We’ll use the entry resource. Again, a simple GET request by curl:
curl http://localhost:8000/api/v1/entry/schema/
This time, we get back a lot more data:
{
"default_format": "application/json",
"fields": {
"body": {
"help_text": "Unicode string data. Ex: \"Hello World\"",
"nullable": false,
"readonly": false,
"type": "string"
},
"id": {
"help_text": "Unicode string data. Ex: \"Hello World\"",
"nullable": false,
"readonly": false,
"type": "string"
},
"pub_date": {
"help_text": "A date & time as a string. Ex: \"2010-11-10T03:07:43\"",
"nullable": false,
"readonly": false,
"type": "datetime"
},
"resource_uri": {
"help_text": "Unicode string data. Ex: \"Hello World\"",
"nullable": false,
"readonly": true,
"type": "string"
},
"slug": {
"help_text": "Unicode string data. Ex: \"Hello World\"",
"nullable": false,
"readonly": false,
"type": "string"
},
"title": {
"help_text": "Unicode string data. Ex: \"Hello World\"",
"nullable": false,
"readonly": false,
"type": "string"
},
"user": {
"help_text": "A single related resource. Can be either a URI or set of nested resource data.",
"nullable": false,
"readonly": false,
"type": "related"
}
},
"filtering": {
"pub_date": ["exact", "lt", "lte", "gte", "gt"],
"user": 2
}
}
This lists out the default_format this resource responds with, the fields on the resource & the filtering options available. This information can be used to prepare the other aspects of the code for the data it can obtain & ways to filter the resources.
Getting A Collection Of Resources¶
Let’s get down to fetching live data. From the api-wide view, we’ll hit the list_endpoint for entry:
curl http://localhost:8000/api/v1/entry/
We get back data that looks like:
{
"meta": {
"limit": 20,
"next": null,
"offset": 0,
"previous": null,
"total_count": 3
},
"objects": [{
"body": "Welcome to my blog!",
"id": "1",
"pub_date": "2011-05-20T00:46:38",
"resource_uri": "/api/v1/entry/1/",
"slug": "first-post",
"title": "First Post",
"user": "/api/v1/user/1/"
},
{
"body": "Well, it's been awhile and I still haven't updated. ",
"id": "2",
"pub_date": "2011-05-21T00:46:58",
"resource_uri": "/api/v1/entry/2/",
"slug": "second-post",
"title": "Second Post",
"user": "/api/v1/user/1/"
},
{
"body": "I'm really excited to get started with this new blog. It's gonna be great!",
"id": "3",
"pub_date": "2011-05-20T00:47:30",
"resource_uri": "/api/v1/entry/3/",
"slug": "my-blog",
"title": "My Blog",
"user": "/api/v1/user/2/"
}]
}
Some things to note:
- By default, you get a paginated set of objects (20 per page is the default).
- In the meta, you get a previous & next. If available, these are URIs to the previous & next pages.
- You get a list of resources/objects under the objects key.
- Each resources/object has a resource_uri field that points to the detail view for that object.
- The foreign key to User is represented as a URI by default. If you’re looking for the full UserResource to be embedded in this view, you’ll need to add full=True to the fields.ToOneField.
If you want to skip paginating, simply run:
curl http://localhost:8000/api/v1/entry/?limit=0
Be warned this will return all objects, so it may be a CPU/IO-heavy operation on large datasets.
Let’s try filtering on the resource. Since we know we can filter on the user, we’ll fetch all posts by the daniel user with:
curl http://localhost:8000/api/v1/entry/?user__username=daniel
We get back what we asked for:
{
"meta": {
"limit": 20,
"next": null,
"offset": 0,
"previous": null,
"total_count": 2
},
"objects": [{
"body": "Welcome to my blog!",
"id": "1",
"pub_date": "2011-05-20T00:46:38",
"resource_uri": "/api/v1/entry/1/",
"slug": "first-post",
"title": "First Post",
"user": "/api/v1/user/1/"
},
{
"body": "Well, it's been awhile and I still haven't updated. ",
"id": "2",
"pub_date": "2011-05-21T00:46:58",
"resource_uri": "/api/v1/entry/2/",
"slug": "second-post",
"title": "Second Post",
"user": "/api/v1/user/1/"
}]
}
Where there were three posts before, now there are only two.
Getting A Detail Resource¶
Since each resource/object in the list view had a resource_uri, let’s explore what’s there:
curl http://localhost:8000/api/v1/entry/1/
We get back a similar set of data that we received from the list view:
{
"body": "Welcome to my blog!",
"id": "1",
"pub_date": "2011-05-20T00:46:38",
"resource_uri": "/api/v1/entry/1/",
"slug": "first-post",
"title": "First Post",
"user": "/api/v1/user/1/"
}
Where this proves useful (for example) is present in the data we got back. We know the URI of the User associated with this blog entry. Let’s run:
curl http://localhost:8000/api/v1/user/1/
Without ever seeing any aspect of the UserResource & just following the URI given, we get back:
{
"date_joined": "2011-05-20T00:42:14.990617",
"first_name": "",
"id": "1",
"last_login": "2011-05-20T00:44:57.510066",
"last_name": "",
"resource_uri": "/api/v1/user/1/",
"username": "daniel"
}
You can do a similar fetch using the following Javascript/jQuery (though be wary of same-domain policy):
$.ajax({
url: 'http://localhost:8000/api/v1/user/1/',
type: 'GET',
accepts: 'application/json',
dataType: 'json'
})
Selecting A Subset Of Resources¶
Sometimes you may want back more than one record, but not an entire list view nor do you want to do multiple requests. Tastypie includes a “set” view, which lets you cherry-pick the objects you want. For example, if we just want the first & third Entry resources, we’d run:
curl "http://localhost:8000/api/v1/entry/set/1;3/"
Note
Quotes are needed in this case because of the semicolon delimiter between primary keys. Without the quotes, bash tries to split it into two statements. No extraordinary quoting will be necessary in your application (unless your API client is written in bash :D).
And we get back just those two objects:
{
"objects": [{
"body": "Welcome to my blog!",
"id": "1",
"pub_date": "2011-05-20T00:46:38",
"resource_uri": "/api/v1/entry/1/",
"slug": "first-post",
"title": "First Post",
"user": "/api/v1/user/1/"
},
{
"body": "I'm really excited to get started with this new blog. It's gonna be great!",
"id": "3",
"pub_date": "2011-05-20T00:47:30",
"resource_uri": "/api/v1/entry/3/",
"slug": "my-blog",
"title": "My Blog",
"user": "/api/v1/user/2/"
}]
}
Note that, like the list view, you get back a list of objects. Unlike the list view, there is NO pagination applied to these objects. You asked for them, you’re going to get them all.
Sending Data¶
Tastypie also gives you full write capabilities in the API. Since the EntryResource has the no-limits Authentication & Authorization on it, we can freely write data.
Warning
Note that this is a huge security hole as well. Don’t put unauthorized write-enabled resources on the Internet, because someone will trash your data.
This is why ReadOnlyAuthorization is the default in Tastypie & why you must override to provide more access.
The good news is that there are no new URLs to learn. The “list” & “detail” URLs we’ve been using to fetch data ALSO support the POST/PUT/DELETE HTTP methods.
Creating A New Resource (POST)¶
Let’s add a new entry. To create new data, we’ll switch from GET requests to the familiar POST request.
Note
Tastypie encourages “round-trippable” data, which means the data you can GET should be able to be POST/PUT’d back to recreate the same object.
If you’re ever in question about what you should send, do a GET on another object & see what Tastypie thinks it should look like.
To create new resources/objects, you will POST to the list endpoint of a resource. Trying to POST to a detail endpoint has a different meaning in the REST mindset (meaning to add a resource as a child of a resource of the same type).
As with all Tastypie requests, the headers we request are important. Since we’ve been using primarily JSON throughout, let’s send a new entry in JSON format:
curl --dump-header - -H "Content-Type: application/json" -X POST --data '{"body": "This will prbbly be my lst post.", "pub_date": "2011-05-22T00:46:38", "slug": "another-post", "title": "Another Post", "user": "/api/v1/user/1/"}' http://localhost:8000/api/v1/entry/
The Content-Type header here informs Tastypie that we’re sending it JSON. We send the data as a JSON-serialized body (NOT as form-data in the form of URL parameters). What we get back is the following response:
HTTP/1.0 201 CREATED
Date: Fri, 20 May 2011 06:48:36 GMT
Server: WSGIServer/0.1 Python/2.7
Content-Type: text/html; charset=utf-8
Location: http://localhost:8000/api/v1/entry/4/
You’ll also note that we get a correct HTTP status code back (201) & a Location header, which gives us the URI to our newly created resource.
Passing --dump-header - is important, because it gives you all the headers as well as the status code. When things go wrong, this will be useful information to help with debugging. For instance, if we send a request without a user:
curl --dump-header - -H "Content-Type: application/json" -X POST --data '{"body": "This will prbbly be my lst post.", "pub_date": "2011-05-22T00:46:38", "slug": "another-post", "title": "Another Post"}' http://localhost:8000/api/v1/entry/
We get back:
HTTP/1.0 400 BAD REQUEST
Date: Fri, 20 May 2011 06:53:02 GMT
Server: WSGIServer/0.1 Python/2.7
Content-Type: text/html; charset=utf-8
The 'user' field has no data and doesn't allow a default or null value.
You can do a similar POST using the following Javascript/jQuery (though be wary of same-domain policy):
# This may require the ``json2.js`` library for older browsers.
var data = JSON.stringify({
"body": "This will prbbly be my lst post.",
"pub_date": "2011-05-22T00:46:38",
"slug": "another-post",
"title": "Another Post"
});
$.ajax({
url: 'http://localhost:8000/api/v1/entry/',
type: 'POST',
contentType: 'application/json',
data: data,
dataType: 'json',
processData: false
})
Updating An Existing Resource (PUT)¶
You might have noticed that we made some typos when we submitted the POST request. We can fix this using a PUT request to the detail endpoint (modify this instance of a resource).:
curl --dump-header - -H "Content-Type: application/json" -X PUT --data '{"body": "This will probably be my last post.", "pub_date": "2011-05-22T00:46:38", "slug": "another-post", "title": "Another Post", "user": "/api/v1/user/1/"}' http://localhost:8000/api/v1/entry/4/
After fixing up the body, we get back:
HTTP/1.0 204 NO CONTENT
Date: Fri, 20 May 2011 07:13:21 GMT
Server: WSGIServer/0.1 Python/2.7
Content-Length: 0
Content-Type: text/html; charset=utf-8
We get a 204 status code, meaning our update was successful. We don’t get a Location header back because we did the PUT on a detail URL, which presumably did not change.
Note
A PUT request requires that the entire resource representation be enclosed. Missing fields may cause errors, or be filled in by default values.
Partially Updating An Existing Resource (PATCH)¶
In some cases, you may not want to send the entire resource when updating. To update just a subset of the fields, we can send a PATCH request to the detail endpoint.:
curl --dump-header - -H "Content-Type: application/json" -X PATCH --data '{"body": "This actually is my last post."}' http://localhost:8000/api/v1/entry/4/
To which we should get back:
HTTP/1.0 202 ACCEPTED
Date: Fri, 20 May 2011 07:13:21 GMT
Server: WSGIServer/0.1 Python/2.7
Content-Length: 0
Content-Type: text/html; charset=utf-8
Updating A Whole Collection Of Resources (PUT)¶
You can also, in rare circumstances, update an entire collection of objects. By sending a PUT request to the list view of a resource, you can replace the entire collection.
Warning
This deletes all of the objects first, then creates the objects afresh. This is done because determining which objects are the same is actually difficult to get correct in the general case for all people.
Send a request like:
curl --dump-header - -H "Content-Type: application/json" -X PUT --data '{"objects": [{"body": "Welcome to my blog!","id": "1","pub_date": "2011-05-20T00:46:38","resource_uri": "/api/v1/entry/1/","slug": "first-post","title": "First Post","user": "/api/v1/user/1/"},{"body": "I'm really excited to get started with this new blog. It's gonna be great!","id": "3","pub_date": "2011-05-20T00:47:30","resource_uri": "/api/v1/entry/3/","slug": "my-blog","title": "My Blog","user": "/api/v1/user/2/"}]}' http://localhost:8000/api/v1/entry/
And you’ll get back a response like:
HTTP/1.0 204 NO CONTENT
Date: Fri, 20 May 2011 07:13:21 GMT
Server: WSGIServer/0.1 Python/2.7
Content-Length: 0
Content-Type: text/html; charset=utf-8
Deleting Data¶
No CRUD setup would be complete without the ability to delete resources/objects. Deleting also requires significantly less complicated requests than POST/PUT.
Deleting A Single Resource¶
We’ve decided that we don’t like the entry we added & edited earlier. Let’s delete it (but leave the other objects alone):
curl --dump-header - -H "Content-Type: application/json" -X DELETE http://localhost:8000/api/v1/entry/4/
Once again, we get back the “Accepted” response of a 204:
HTTP/1.0 204 NO CONTENT
Date: Fri, 20 May 2011 07:28:01 GMT
Server: WSGIServer/0.1 Python/2.7
Content-Length: 0
Content-Type: text/html; charset=utf-8
If we request that resource, we get a 410 to show it’s no longer there:
curl --dump-header - http://localhost:8000/api/v1/entry/4/
HTTP/1.0 410 GONE
Date: Fri, 20 May 2011 07:29:02 GMT
Server: WSGIServer/0.1 Python/2.7
Content-Type: text/html; charset=utf-8
Additionally, if we try to run the DELETE again (using the same original command), we get the “Gone” response again:
HTTP/1.0 410 GONE
Date: Fri, 20 May 2011 07:30:00 GMT
Server: WSGIServer/0.1 Python/2.7
Content-Type: text/html; charset=utf-8
Deleting A Whole Collection Of Resources¶
Finally, it’s possible to remove an entire collection of resources. This is as destructive as it sounds. Once again, we use the DELETE method, this time on the entire list endpoint:
curl --dump-header - -H "Content-Type: application/json" -X DELETE http://localhost:8000/api/v1/entry/
As a response, we get:
HTTP/1.0 204 NO CONTENT
Date: Fri, 20 May 2011 07:32:51 GMT
Server: WSGIServer/0.1 Python/2.7
Content-Length: 0
Content-Type: text/html; charset=utf-8
Hitting the list view:
curl --dump-header - http://localhost:8000/api/v1/entry/
Gives us a 200 but no objects:
{
"meta": {
"limit": 20,
"next": null,
"offset": 0,
"previous": null,
"total_count": 0
},
"objects": []
}
Bulk Operations¶
As an optimization, it is possible to do many creations, updates, and deletions to a collection in a single request by sending a PATCH to the list endpoint.:
curl --dump-header - -H "Content-Type: application/json" -X PATCH --data '{"objects": [{"body": "Surprise! Another post!.", "pub_date": "2012-02-16T00:46:38", "slug": "yet-another-post", "title": "Yet Another Post"}], "deleted_objects": ["http://localhost:8000/api/v1/entry/4/"]}' http://localhost:8000/api/v1/entry/
We should get back:
HTTP/1.0 202 ACCEPTED
Date: Fri, 16 Feb 2012 00:46:38 GMT
Server: WSGIServer/0.1 Python/2.7
Content-Length: 0
Content-Type: text/html; charset=utf-8
The Accepted response means the server has accepted the request, but gives no details on the result. In order to see any created resources, we would need to do a get GET on the list endpoint.
For detailed information on the format of a bulk request, see patch_list.
You Did It!¶
That’s a whirlwind tour of interacting with a Tastypie API. There’s additional functionality present, such as:
- POST/PUT the other supported content-types
- More filtering/order_by/limit/offset tricks
- Using overridden URLconfs to support complex or non-PK lookups
- Authentication
But this grounds you in the basics & hopefully clarifies usage/debugging better.
Tastypie Settings¶
This is a comprehensive list of the settings Tastypie recognizes.
API_LIMIT_PER_PAGE¶
Optional
This setting controls the default number of records Tastypie will show in a list view.
This is only used when a user does not specify a limit GET parameter and the Resource subclass has not overridden the number to be shown.
An example:
API_LIMIT_PER_PAGE = 50
If you don’t want to limit the number of records by default, you can set this setting to 0:
API_LIMIT_PER_PAGE = 0
Defaults to 20.
TASTYPIE_FULL_DEBUG¶
Optional
This setting controls what the behavior is when an unhandled exception occurs.
If set to True and settings.DEBUG = True, the standard Django technical 500 is displayed.
If not set or set to False, Tastypie will return a serialized response. If settings.DEBUG is True, you’ll get the actual exception message plus a traceback. If settings.DEBUG is False, Tastypie will call mail_admins() and provide a canned error message (which you can override with TASTYPIE_CANNED_ERROR) in the response.
An example:
TASTYPIE_FULL_DEBUG = True
Defaults to False.
TASTYPIE_CANNED_ERROR¶
Optional
This setting allows you to override the canned error response when an unhandled exception is raised and settings.DEBUG is False.
An example:
TASTYPIE_CANNED_ERROR = "Oops, we broke it!"
Defaults to "Sorry, this request could not be processed. Please try again later.".
TASTYPIE_ALLOW_MISSING_SLASH¶
Optional
This setting allows your URLs to be missing the final slash. Useful for integrating with other systems.
You must also have settings.APPEND_SLASH = False so that Django does not emit HTTP 302 redirects.
An example:
TASTYPIE_ALLOW_MISSING_SLASH = True
Defaults to False.
TASTYPIE_DATETIME_FORMATTING¶
Optional
This setting allows you to globally choose what format your datetime/date/time data will be formatted in. Valid options are iso-8601, iso-8601-strict & rfc-2822.
An example:
TASTYPIE_DATETIME_FORMATTING = 'rfc-2822'
Defaults to iso-8601. iso-8601 includes microseconds if available, use iso-8601-strict to strip them.
TASTYPIE_DEFAULT_FORMATS¶
Optional
This setting allows you to globally configure the list of allowed serialization formats for your entire site.
An example:
TASTYPIE_DEFAULT_FORMATS = ['json', 'xml']
Defaults to ['json', 'xml', 'yaml', 'html', 'plist'].
TASTYPIE_ABSTRACT_APIKEY¶
Optional
This setting makes the ApiKey model an abstract base class. This may be useful in multi-database setups where many databases each have their own table for user data and ApiKeyAuthentication is not used. Without this setting, the tastypie_apikey table would have to be created on each database containing user account data (such as Django’s built-in auth_user table generated by django.contrib.auth.models.User). Valid options are True & False.
An example:
TASTYPIE_ABSTRACT_APIKEY = True
Defaults to False.
Using Tastypie With Non-ORM Data Sources¶
Much of this documentation demonstrates the use of Tastypie with Django’s ORM. You might think that Tastypie depended on the ORM, when in fact, it was purpose-built to handle non-ORM data. This documentation should help you get started providing APIs using other data sources.
Virtually all of the code that makes Tastypie actually process requests & return data is within the Resource class. ModelResource is actually a light wrapper around Resource that provides ORM-specific access. The methods that ModelResource overrides are the same ones you’ll need to override when hooking up your data source.
Approach¶
When working with Resource, many things are handled for you. All the authentication/authorization/caching/serialization/throttling bits should work as normal and Tastypie can support all the REST-style methods. Schemas & discovery views all work the same as well.
What you don’t get out of the box are the fields you’re choosing to expose & the lowest level data access methods. If you want a full read-write API, there are nine methods you need to implement. They are:
- detail_uri_kwargs
- get_object_list
- obj_get_list
- obj_get
- obj_create
- obj_update
- obj_delete_list
- obj_delete
- rollback
If read-only is all you’re exposing, you can cut that down to four methods to override.
Using Riak for MessageResource¶
As an example, we’ll take integrating with Riak (a Dynamo-like NoSQL store) since it has both a simple API and demonstrate what hooking up to a non-relational datastore looks like:
# We need a generic object to shove data in/get data from.
# Riak generally just tosses around dictionaries, so we'll lightly
# wrap that.
class RiakObject(object):
def __init__(self, initial=None):
self.__dict__['_data'] = {}
if hasattr(initial, 'items'):
self.__dict__['_data'] = initial
def __getattr__(self, name):
return self._data.get(name, None)
def __setattr__(self, name, value):
self.__dict__['_data'][name] = value
def to_dict(self):
return self._data
class MessageResource(Resource):
# Just like a Django ``Form`` or ``Model``, we're defining all the
# fields we're going to handle with the API here.
uuid = fields.CharField(attribute='uuid')
user_uuid = fields.CharField(attribute='user_uuid')
message = fields.CharField(attribute='message')
created = fields.IntegerField(attribute='created')
class Meta:
resource_name = 'riak'
object_class = RiakObject
authorization = Authorization()
# Specific to this resource, just to get the needed Riak bits.
def _client(self):
return riak.RiakClient()
def _bucket(self):
client = self._client()
# Note that we're hard-coding the bucket to use. Fine for
# example purposes, but you'll want to abstract this.
return client.bucket('messages')
# The following methods will need overriding regardless of your
# data source.
def detail_uri_kwargs(self, bundle_or_obj):
kwargs = {}
if isinstance(bundle_or_obj, Bundle):
kwargs['pk'] = bundle_or_obj.obj.uuid
else:
kwargs['pk'] = bundle_or_obj.uuid
return kwargs
def get_object_list(self, request):
query = self._client().add('messages')
query.map("function(v) { var data = JSON.parse(v.values[0].data); return [[v.key, data]]; }")
results = []
for result in query.run():
new_obj = RiakObject(initial=result[1])
new_obj.uuid = result[0]
results.append(new_obj)
return results
def obj_get_list(self, request=None, **kwargs):
# Filtering disabled for brevity...
return self.get_object_list(request)
def obj_get(self, request=None, **kwargs):
bucket = self._bucket()
message = bucket.get(kwargs['pk'])
return RiakObject(initial=message.get_data())
def obj_create(self, bundle, request=None, **kwargs):
bundle.obj = RiakObject(initial=kwargs)
bundle = self.full_hydrate(bundle)
bucket = self._bucket()
new_message = bucket.new(bundle.obj.uuid, data=bundle.obj.to_dict())
new_message.store()
return bundle
def obj_update(self, bundle, request=None, **kwargs):
return self.obj_create(bundle, request, **kwargs)
def obj_delete_list(self, request=None, **kwargs):
bucket = self._bucket()
for key in bucket.get_keys():
obj = bucket.get(key)
obj.delete()
def obj_delete(self, request=None, **kwargs):
bucket = self._bucket()
obj = bucket.get(kwargs['pk'])
obj.delete()
def rollback(self, bundles):
pass
This represents a full, working, Riak-powered API endpoint. All REST-style actions (GET/POST/PUT/DELETE) all work correctly. The only shortcut taken in this example was skipping filter-abilty, as adding in the MapReduce bits would have decreased readability.
All said and done, just nine methods needed overriding, eight of which were highly specific to how data access is done.
Tools¶
Here are some tools that might help in interacting with the API that Tastypie provides:
Browser¶
JSONView¶
- Firefox - https://addons.mozilla.org/en-US/firefox/addon/jsonview/
- Chrome - https://chrome.google.com/webstore/detail/chklaanhfefbnpoihckbnefhakgolnmc
A plugin (actually two different ones that closely mirror each other) that nicely reformats JSON data in the browser.
Extensions¶
Tastypie-msgpack¶
https://github.com/stephenmcd/tastypie-msgpack
Adds MsgPack support to Tastypie’s serializer.
Python¶
Slumber¶
Slumber is a small Python library that makes it easy to access & work with APIs. It works for many others, but works especially well with Tastypie.
Hammock¶
https://github.com/kadirpekel/hammock
Hammock is a fun module lets you deal with rest APIs by converting them into dead simple programmatic APIs. It uses popular requests module in backyard to provide full-fledged rest experience.
Here is what it looks like:
>>> import hammock
>>> api = hammock.Hammock('http://localhost:8000')
>>> api.users('foo').posts('bar').comments.GET()
<Response [200]>
drest¶
drest is another small Python library. It focuses on extensibility & can also work with many different API, with an emphasis on Tastypie.
json.tool¶
Included with Python, this tool makes reformatting JSON easy. For example:
$ curl http://localhost:8000/api/v1/note/ | python -m json.tool
Will return nicely reformatted data like:
{
"meta": {
"total_count": 1
},
"objects": [
{
"content": "Hello world!",
"user": "/api/v1/user/1/"
}
]
}
Javascript¶
backbone-tastypie¶
https://github.com/PaulUithol/backbone-tastypie
A small layer that makes Backbone & Tastypie plan nicely together.
backbone-relational¶
https://github.com/PaulUithol/Backbone-relational/
Allows Backbone to work with relational data, like the kind of data Tastypie provides.
Testing¶
Having integrated unit tests that cover your API’s behavior is important, as it helps provide verification that your API code is still valid & working correctly with the rest of your application.
Tastypie provides some basic facilities that build on top of Django’s testing support, in the form of a specialized TestApiClient & ResourceTestCase.
The ResourceTestCase builds on top of Django’s TestCase. It provides quite a few extra assertion methods that are specific to APIs. Under the hood, it uses the TestApiClient to perform requests properly.
The TestApiClient builds on & exposes an interface similar to that of Django’s Client. However, under the hood, it hands all the setup needed to construct a proper request.
Example Usage¶
The typical use case will primarily consist of subclassing the ResourceTestCase class & using the built-in assertions to ensure your API is behaving correctly. For the purposes of this example, we’ll assume the resource in question looks like:
from tastypie.authentication import BasicAuthentication
from tastypie.resources import ModelResource
from entries.models import Entry
class EntryResource(ModelResource):
class Meta:
queryset = Entry.objects.all()
authentication = BasicAuthentication()
An example usage might look like:
import datetime
from django.contrib.auth.models import User
from tastypie.test import ResourceTestCase
from entries.models import Entry
class EntryResourceTest(ResourceTestCase):
# Use ``fixtures`` & ``urls`` as normal. See Django's ``TestCase``
# documentation for the gory details.
fixtures = ['test_entries.json']
def setUp(self):
super(EntryResourceTest, self).setUp()
# Create a user.
self.username = 'daniel'
self.password = 'pass'
self.user = User.objects.create_user(self.username, 'daniel@example.com', self.password)
# Fetch the ``Entry`` object we'll use in testing.
# Note that we aren't using PKs because they can change depending
# on what other tests are running.
self.entry_1 = Entry.objects.get(slug='first-post')
# We also build a detail URI, since we will be using it all over.
# DRY, baby. DRY.
self.detail_url = '/api/v1/entry/{0}/'.format(self.entry_1.pk)
# The data we'll send on POST requests. Again, because we'll use it
# frequently (enough).
self.post_data = {
'user': '/api/v1/user/{0}/'.format(self.user.pk),
'title': 'Second Post!',
'slug': 'second-post',
'created': '2012-05-01T22:05:12'
}
def get_credentials(self):
return self.create_basic(username=self.username, password=self.password)
def test_get_list_unauthorzied(self):
self.assertHttpUnauthorized(self.api_client.get('/api/v1/entries/', format='json'))
def test_get_list_json(self):
resp = self.api_client.get('/api/v1/entries/', format='json', authentication=self.get_credentials())
self.assertValidJSONResponse(resp)
# Scope out the data for correctness.
self.assertEqual(len(self.deserialize(resp)['objects']), 12)
# Here, we're checking an entire structure for the expected data.
self.assertEqual(self.deserialize(resp)['objects'][0], {
'pk': str(self.entry_1.pk),
'user': '/api/v1/user/{0}/'.format(self.user.pk),
'title': 'First post',
'slug': 'first-post',
'created': '2012-05-01T19:13:42',
'resource_uri': '/api/v1/entry/{0}/'.format(self.entry_1.pk)
})
def test_get_list_xml(self):
self.assertValidXMLResponse(self.api_client.get('/api/v1/entries/', format='xml', authentication=self.get_credentials()))
def test_get_detail_unauthenticated(self):
self.assertHttpUnauthorized(self.api_client.get(self.detail_url, format='json'))
def test_get_detail_json(self):
resp = self.api_client.get(self.detail_url, format='json', authentication=self.get_credentials())
self.assertValidJSONResponse(resp)
# We use ``assertKeys`` here to just verify the keys, not all the data.
self.assertKeys(self.deserialize(resp), ['created', 'slug', 'title', 'user'])
self.assertEqual(self.deserialize(resp)['name'], 'First post')
def test_get_detail_xml(self):
self.assertValidXMLResponse(self.api_client.get(self.detail_url, format='xml', authentication=self.get_credentials()))
def test_post_list_unauthenticated(self):
self.assertHttpUnauthorized(self.api_client.post('/api/v1/entries/', format='json', data=self.post_data))
def test_post_list(self):
# Check how many are there first.
self.assertEqual(Entry.objects.count(), 5)
self.assertHttpCreated(self.api_client.post('/api/v1/entries/', format='json', data=self.post_data, authentication=self.get_credentials()))
# Verify a new one has been added.
self.assertEqual(Entry.objects.count(), 6)
def test_put_detail_unauthenticated(self):
self.assertHttpUnauthorized(self.api_client.put(self.detail_url, format='json', data={}))
def test_put_detail(self):
# Grab the current data & modify it slightly.
original_data = self.deserialize(self.api_client.get(self.detail_url, format='json', authentication=self.get_credentials()))
new_data = original_data.copy()
new_data['title'] = 'Updated: First Post'
new_data['created'] = '2012-05-01T20:06:12'
self.assertEqual(Entry.objects.count(), 5)
self.assertHttpAccepted(self.api_client.put(self.detail_url, format='json', data=new_data, authentication=self.get_credentials()))
# Make sure the count hasn't changed & we did an update.
self.assertEqual(Entry.objects.count(), 5)
# Check for updated data.
self.assertEqual(Entry.objects.get(pk=25).title, 'Updated: First Post')
self.assertEqual(Entry.objects.get(pk=25).slug, 'first-post')
self.assertEqual(Entry.objects.get(pk=25).created, datetime.datetime(2012, 3, 1, 13, 6, 12))
def test_delete_detail_unauthenticated(self):
self.assertHttpUnauthorized(self.api_client.delete(self.detail_url, format='json'))
def test_delete_detail(self):
self.assertEqual(Entry.objects.count(), 5)
self.assertHttpAccepted(self.api_client.delete(self.detail_url, format='json', authentication=self.get_credentials()))
self.assertEqual(Entry.objects.count(), 4)
Note that this example doesn’t cover other cases, such as filtering, PUT to a list endpoint, DELETE to a list endpoint, PATCH support, etc.
ResourceTestCase API Reference¶
The ResourceTestCase exposes the following methods for use. Most are enhanced assertions or provide API-specific behaviors.
get_credentials¶
- ResourceTestCase.get_credentials(self)¶
A convenience method for the user as a way to shorten up the often repetitious calls to create the same authentication.
Raises NotImplementedError by default.
Usage:
class MyResourceTestCase(ResourceTestCase):
def get_credentials(self):
return self.create_basic('daniel', 'pass')
# Then the usual tests...
create_basic¶
- ResourceTestCase.create_basic(self, username, password)¶
Creates & returns the HTTP Authorization header for use with BASIC Auth.
create_apikey¶
- ResourceTestCase.create_apikey(self, username, api_key)¶
Creates & returns the HTTP Authorization header for use with ApiKeyAuthentication.
create_digest¶
- ResourceTestCase.create_digest(self, username, api_key, method, uri)¶
Creates & returns the HTTP Authorization header for use with Digest Auth.
create_oauth¶
- ResourceTestCase.create_oauth(self, user)¶
Creates & returns the HTTP Authorization header for use with Oauth.
assertHttpOK¶
- ResourceTestCase.assertHttpOK(self, resp)¶
Ensures the response is returning a HTTP 200.
assertHttpCreated¶
- ResourceTestCase.assertHttpCreated(self, resp)¶
Ensures the response is returning a HTTP 201.
assertHttpAccepted¶
- ResourceTestCase.assertHttpAccepted(self, resp)¶
Ensures the response is returning either a HTTP 202 or a HTTP 204.
assertHttpMultipleChoices¶
- ResourceTestCase.assertHttpMultipleChoices(self, resp)¶
Ensures the response is returning a HTTP 300.
assertHttpSeeOther¶
- ResourceTestCase.assertHttpSeeOther(self, resp)¶
Ensures the response is returning a HTTP 303.
assertHttpNotModified¶
- ResourceTestCase.assertHttpNotModified(self, resp)¶
Ensures the response is returning a HTTP 304.
assertHttpBadRequest¶
- ResourceTestCase.assertHttpBadRequest(self, resp)¶
Ensures the response is returning a HTTP 400.
assertHttpForbidden¶
- ResourceTestCase.assertHttpForbidden(self, resp)¶
Ensures the response is returning a HTTP 403.
assertHttpNotFound¶
- ResourceTestCase.assertHttpNotFound(self, resp)¶
Ensures the response is returning a HTTP 404.
assertHttpMethodNotAllowed¶
- ResourceTestCase.assertHttpMethodNotAllowed(self, resp)¶
Ensures the response is returning a HTTP 405.
assertHttpConflict¶
- ResourceTestCase.assertHttpConflict(self, resp)¶
Ensures the response is returning a HTTP 409.
assertHttpGone¶
- ResourceTestCase.assertHttpGone(self, resp)¶
Ensures the response is returning a HTTP 410.
assertHttpTooManyRequests¶
- ResourceTestCase.assertHttpTooManyRequests(self, resp)¶
Ensures the response is returning a HTTP 429.
assertHttpApplicationError¶
- ResourceTestCase.assertHttpApplicationError(self, resp)¶
Ensures the response is returning a HTTP 500.
assertHttpNotImplemented¶
- ResourceTestCase.assertHttpNotImplemented(self, resp)¶
Ensures the response is returning a HTTP 501.
assertValidJSON¶
- ResourceTestCase.assertValidJSON(self, data)¶
Given the provided data as a string, ensures that it is valid JSON & can be loaded properly.
assertValidXML¶
- ResourceTestCase.assertValidXML(self, data)¶
Given the provided data as a string, ensures that it is valid XML & can be loaded properly.
assertValidYAML¶
- ResourceTestCase.assertValidYAML(self, data)¶
Given the provided data as a string, ensures that it is valid YAML & can be loaded properly.
assertValidPlist¶
- ResourceTestCase.assertValidPlist(self, data)¶
Given the provided data as a string, ensures that it is valid binary plist & can be loaded properly.
assertValidJSONResponse¶
- ResourceTestCase.assertValidJSONResponse(self, resp)¶
Given a HttpResponse coming back from using the client, assert that you get back:
- An HTTP 200
- The correct content-type (application/json)
- The content is valid JSON
assertValidXMLResponse¶
- ResourceTestCase.assertValidXMLResponse(self, resp)¶
Given a HttpResponse coming back from using the client, assert that you get back:
- An HTTP 200
- The correct content-type (application/xml)
- The content is valid XML
assertValidYAMLResponse¶
- ResourceTestCase.assertValidYAMLResponse(self, resp)¶
Given a HttpResponse coming back from using the client, assert that you get back:
- An HTTP 200
- The correct content-type (text/yaml)
- The content is valid YAML
assertValidPlistResponse¶
- ResourceTestCase.assertValidPlistResponse(self, resp)¶
Given a HttpResponse coming back from using the client, assert that you get back:
- An HTTP 200
- The correct content-type (application/x-plist)
- The content is valid binary plist data
deserialize¶
- ResourceTestCase.deserialize(self, resp)¶
Given a HttpResponse coming back from using the client, this method checks the Content-Type header & attempts to deserialize the data based on that.
It returns a Python datastructure (typically a dict) of the serialized data.
serialize¶
- ResourceTestCase.serialize(self, data, format='application/json')¶
Given a Python datastructure (typically a dict) & a desired content-type, this method will return a serialized string of that data.
assertKeys¶
- ResourceTestCase.assertKeys(self, data, expected)¶
This method ensures that the keys of the data match up to the keys of expected.
It covers the (extremely) common case where you want to make sure the keys of a response match up to what is expected. This is typically less fragile than testing the full structure, which can be prone to data changes.
TestApiClient API Reference¶
The TestApiClient simulates a HTTP client making calls to the API. It’s important to note that it uses Django’s testing infrastructure, so it’s not making actual calls against a webserver.
__init__¶
- TestApiClient.__init__(self, serializer=None)¶
Sets up a fresh TestApiClient instance.
If you are employing a custom serializer, you can pass the class to the serializer= kwarg.
get_content_type¶
- TestApiClient.get_content_type(self, short_format)¶
Given a short name (such as json or xml), returns the full content-type for it (application/json or application/xml in this case).
get¶
- TestApiClient.get(self, uri, format='json', data=None, authentication=None, **kwargs)¶
Performs a simulated GET request to the provided URI.
Optionally accepts a data kwarg, which in the case of GET, lets you send along GET parameters. This is useful when testing filtering or other things that read off the GET params. Example:
from tastypie.test import TestApiClient
client = TestApiClient()
response = client.get('/api/v1/entry/1/', data={'format': 'json', 'title__startswith': 'a', 'limit': 20, 'offset': 60})
Optionally accepts an authentication kwarg, which should be an HTTP header with the correct authentication data already setup.
All other **kwargs passed in get passed through to the Django TestClient. See https://docs.djangoproject.com/en/dev/topics/testing/#module-django.test.client for details.
post¶
- TestApiClient.post(self, uri, format='json', data=None, authentication=None, **kwargs)¶
Performs a simulated POST request to the provided URI.
Optionally accepts a data kwarg. Unlike GET, in POST the data gets serialized & sent as the body instead of becoming part of the URI. Example:
from tastypie.test import TestApiClient
client = TestApiClient()
response = client.post('/api/v1/entry/', data={
'created': '2012-05-01T20:02:36',
'slug': 'another-post',
'title': 'Another Post',
'user': '/api/v1/user/1/',
})
Optionally accepts an authentication kwarg, which should be an HTTP header with the correct authentication data already setup.
All other **kwargs passed in get passed through to the Django TestClient. See https://docs.djangoproject.com/en/dev/topics/testing/#module-django.test.client for details.
put¶
- TestApiClient.put(self, uri, format='json', data=None, authentication=None, **kwargs)¶
Performs a simulated PUT request to the provided URI.
Optionally accepts a data kwarg. Unlike GET, in PUT the data gets serialized & sent as the body instead of becoming part of the URI. Example:
from tastypie.test import TestApiClient
client = TestApiClient()
response = client.put('/api/v1/entry/1/', data={
'created': '2012-05-01T20:02:36',
'slug': 'another-post',
'title': 'Another Post',
'user': '/api/v1/user/1/',
})
Optionally accepts an authentication kwarg, which should be an HTTP header with the correct authentication data already setup.
All other **kwargs passed in get passed through to the Django TestClient. See https://docs.djangoproject.com/en/dev/topics/testing/#module-django.test.client for details.
patch¶
- TestApiClient.patch(self, uri, format='json', data=None, authentication=None, **kwargs)¶
Performs a simulated PATCH request to the provided URI.
Optionally accepts a data kwarg. Unlike GET, in PATCH the data gets serialized & sent as the body instead of becoming part of the URI. Example:
from tastypie.test import TestApiClient
client = TestApiClient()
response = client.patch('/api/v1/entry/1/', data={
'created': '2012-05-01T20:02:36',
'slug': 'another-post',
'title': 'Another Post',
'user': '/api/v1/user/1/',
})
Optionally accepts an authentication kwarg, which should be an HTTP header with the correct authentication data already setup.
All other **kwargs passed in get passed through to the Django TestClient. See https://docs.djangoproject.com/en/dev/topics/testing/#module-django.test.client for details.
delete¶
- TestApiClient.delete(self, uri, format='json', data=None, authentication=None, **kwargs)¶
Performs a simulated DELETE request to the provided URI.
Optionally accepts a data kwarg, which in the case of DELETE, lets you send along DELETE parameters. This is useful when testing filtering or other things that read off the DELETE params. Example:
from tastypie.test import TestApiClient
client = TestApiClient()
response = client.delete('/api/v1/entry/1/', data={'format': 'json'})
Optionally accepts an authentication kwarg, which should be an HTTP header with the correct authentication data already setup.
All other **kwargs passed in get passed through to the Django TestClient. See https://docs.djangoproject.com/en/dev/topics/testing/#module-django.test.client for details.
Compatibility Notes¶
Tastypie does its best to be a good third-party app, trying to interoperate with the widest range of Django environments it can. However, there are times where certain things aren’t possible. We’ll do our best to document them here.
ApiKey Database Index¶
When the ApiKey model was added to Tastypie, an index was lacking on the key field. This was the case until the v0.9.12 release. The model was updated & a migration was added (0002_add_apikey_index.py). However, due to the way MySQL works & the way Django generates index names, this migration would fail miserably on many MySQL installs.
If you are using MySQL, South & the ApiKey authentication class, you should manually add an index for the the ApiKey.key field. Something to the effect of:
BEGIN; -- LOLMySQL
CREATE INDEX tastypie_apikey_key_index ON tastypie_apikey (`key`);
COMMIT;
Resources¶
In terms of a REST-style architecture, a “resource” is a collection of similar data. This data could be a table of a database, a collection of other resources or a similar form of data storage. In Tastypie, these resources are generally intermediaries between the end user & objects, usually Django models. As such, Resource (and its model-specific twin ModelResource) form the heart of Tastypie’s functionality.
Quick Start¶
A sample resource definition might look something like:
from django.contrib.auth.models import User
from tastypie import fields
from tastypie.authorization import DjangoAuthorization
from tastypie.resources import ModelResource, ALL, ALL_WITH_RELATIONS
from myapp.models import Entry
class UserResource(ModelResource):
class Meta:
queryset = User.objects.all()
resource_name = 'auth/user'
excludes = ['email', 'password', 'is_superuser']
class EntryResource(ModelResource):
user = fields.ForeignKey(UserResource, 'user')
class Meta:
queryset = Entry.objects.all()
list_allowed_methods = ['get', 'post']
detail_allowed_methods = ['get', 'post', 'put', 'delete']
resource_name = 'myapp/entry'
authorization = DjangoAuthorization()
filtering = {
'slug': ALL,
'user': ALL_WITH_RELATIONS,
'created': ['exact', 'range', 'gt', 'gte', 'lt', 'lte'],
}
Why Class-Based?¶
Using class-based resources make it easier to extend/modify the code to meet your needs. APIs are rarely a one-size-fits-all problem space, so Tastypie tries to get the fundamentals right and provide you with enough hooks to customize things to work your way.
As is standard, this raises potential problems for thread-safety. Tastypie has been designed to minimize the possibility of data “leaking” between threads. This does however sometimes introduce some small complexities & you should be careful not to store state on the instances if you’re going to be using the code in a threaded environment.
Why Resource vs. ModelResource?¶
Make no mistake that Django models are far and away the most popular source of data. However, in practice, there are many times where the ORM isn’t the data source. Hooking up things like a NoSQL store (see Using Tastypie With Non-ORM Data Sources), a search solution like Haystack or even managed filesystem data are all good use cases for Resource knowing nothing about the ORM.
Flow Through The Request/Response Cycle¶
Tastypie can be thought of as a set of class-based views that provide the API functionality. As such, many part of the request/response cycle are standard Django behaviors. For instance, all routing/middleware/response-handling aspects are the same as a typical Django app. Where it differs is in the view itself.
As an example, we’ll walk through what a GET request to a list endpoint (say /api/v1/user/?format=json) looks like:
The Resource.urls are checked by Django’s url resolvers.
On a match for the list view, Resource.wrap_view('dispatch_list') is called. wrap_view provides basic error handling & allows for returning serialized errors.
Because dispatch_list was passed to wrap_view, Resource.dispatch_list is called next. This is a thin wrapper around Resource.dispatch.
dispatch does a bunch of heavy lifting. It ensures:
- the requested HTTP method is in allowed_methods (method_check),
- the class has a method that can handle the request (get_list),
- the user is authenticated (is_authenticated),
- the user is authorized (is_authorized),
- & the user has not exceeded their throttle (throttle_check).
At this point, dispatch actually calls the requested method (get_list).
get_list does the actual work of the API. It does:
- A fetch of the available objects via Resource.obj_get_list. In the case of ModelResource, this builds the ORM filters to apply (ModelResource.build_filters). It then gets the QuerySet via ModelResource.get_object_list (which performs Resource.apply_authorization_limits to possibly limit the set the user can work with) and applies the built filters to it.
- It then sorts the objects based on user input (ModelResource.apply_sorting).
- Then it paginates the results using the supplied Paginator & pulls out the data to be serialized.
- The objects in the page have full_dehydrate applied to each of them, causing Tastypie to translate the raw object data into the fields the endpoint supports.
- Finally, it calls Resource.create_response.
create_response is a shortcut method that:
- Determines the desired response format (Resource.determine_format),
- Serializes the data given to it in the proper format,
- And returns a Django HttpResponse (200 OK) with the serialized data.
We bubble back up the call stack to dispatch. The last thing dispatch does is potentially store that a request occurred for future throttling (Resource.log_throttled_access) then either returns the HttpResponse or wraps whatever data came back in a response (so Django doesn’t freak out).
Processing on other endpoints or using the other HTTP methods results in a similar cycle, usually differing only in what “actual work” method gets called (which follows the format of “<http_method>_<list_or_detail>”). In the case of POST/PUT, the hydrate cycle additionally takes place and is used to take the user data & convert it to raw data for storage.
Why Resource URIs?¶
Resource URIs play a heavy role in how Tastypie delivers data. This can seem very different from other solutions which simply inline related data. Though Tastypie can inline data like that (using full=True on the field with the relation), the default is to provide URIs.
URIs are useful because it results in smaller payloads, letting you fetch only the data that is important to you. You can imagine an instance where an object has thousands of related items that you may not be interested in.
URIs are also very cache-able, because the data at each endpoint is less likely to frequently change.
And URIs encourage proper use of each endpoint to display the data that endpoint covers.
Ideology aside, you should use whatever suits you. If you prefer fewer requests & fewer endpoints, use of full=True is available, but be aware of the consequences of each approach.
Accessing The Current Request¶
Being able to change behavior based on the current request is a very commmon need. Virtually anywhere within Resource/ModelResource, if a bundle is available, you can access it using bundle.request. This is useful for altering querysets, ensuring headers are present, etc.
Most methods you may need to override/extend should get a bundle passed to them.
If you’re using the Resource/ModelResource directly, with no request available, an empty Request will be supplied instead. If this is a common pattern/usage in your code, you’ll want to accommodate for data that potentially isn’t there.
Advanced Data Preparation¶
Not all data can be easily pull off an object/model attribute. And sometimes, you (or the client) may need to send data that doesn’t neatly fit back into the data model on the server side. For this, Tastypie has the “dehydrate/hydrate” cycle.
The Dehydrate Cycle¶
Tastypie uses a “dehydrate” cycle to prepare data for serialization, which is to say that it takes the raw, potentially complicated data model & turns it into a (generally simpler) processed data structure for client consumption. This usually means taking a complex data object & turning it into a dictionary of simple data types.
Broadly speaking, this takes the bundle.obj instance & builds bundle.data, which is what is actually serialized.
The cycle looks like:
- Put the data model into a Bundle instance, which is then passed through the various methods.
- Run through all fields on the Resource, letting each field perform its own dehydrate method on the bundle.
- While processing each field, look for a dehydrate_<fieldname> method on the Resource. If it’s present, call it with the bundle.
- Finally, after all fields are processed, if the dehydrate method is present on the Resource, it is called & given the entire bundle.
The goal of this cycle is to populate the bundle.data dictionary with data suitable for serialization. With the exception of the alter_* methods (as hooks to manipulate the overall structure), this cycle controls what is actually handed off to be serialized & sent to the client.
Per-field dehydrate¶
Each field (even custom ApiField subclasses) has its own dehydrate method. If it knows how to access data (say, given the attribute kwarg), it will attempt to populate values itself.
The return value is put in the bundle.data dictionary (by the Resource) with the fieldname as the key.
dehydrate_FOO¶
Since not all data may be ready for consumption based on just attribute access (or may require an advanced lookup/calculation), this hook enables you to fill in data or massage whatever the field generated.
Note
The FOO here is not literal. Instead, it is a placeholder that should be replaced with the fieldname in question.
Defining these methods is especially common when denormalizing related data, providing statistics or filling in unrelated data.
A simple example:
class MyResource(ModelResource):
# The ``title`` field is already added to the class by ``ModelResource``
# and populated off ``Note.title``. But we want allcaps titles...
class Meta:
queryset = Note.objects.all()
def dehydrate_title(self, bundle):
return bundle.data['title'].upper()
A complex example:
class MyResource(ModelResource):
# As is, this is just an empty field. Without the ``dehydrate_rating``
# method, no data would be populated for it.
rating = fields.FloatField(readonly=True)
class Meta:
queryset = Note.objects.all()
def dehydrate_rating(self, bundle):
total_score = 0.0
# Make sure we don't have to worry about "divide by zero" errors.
if not bundle.obj.rating_set.count():
return rating
# We'll run over all the ``Rating`` objects & calculate an average.
for rating in bundle.obj.rating_set.all():
total_score += rating.rating
return total_score / bundle.obj.rating_set.count()
The return value is updated in the bundle.data. You should avoid altering bundle.data here if you can help it.
dehydrate¶
The dehydrate method takes a now fully-populated bundle.data & make any last alterations to it. This is useful for when a piece of data might depend on more than one field, if you want to shove in extra data that isn’t worth having its own field or if you want to dynamically remove things from the data to be returned.
A simple example:
class MyResource(ModelResource):
class Meta:
queryset = Note.objects.all()
def dehydrate(self, bundle):
# Include the request IP in the bundle.
bundle.data['request_ip'] = bundle.request.META.get('REMOTE_ADDR')
return bundle
A complex example:
class MyResource(ModelResource):
class Meta:
queryset = User.objects.all()
excludes = ['email', 'password', 'is_staff', 'is_superuser']
def dehydrate(self, bundle):
# If they're requesting their own record, add in their email address.
if bundle.request.user.pk == bundle.obj.pk:
# Note that there isn't an ``email`` field on the ``Resource``.
# By this time, it doesn't matter, as the built data will no
# longer be checked against the fields on the ``Resource``.
bundle.data['email'] = bundle.obj.email
return bundle
This method should return a bundle, whether it modifies the existing one or creates a whole new one. You can even remove any/all data from the bundle.data if you wish.
The Hydrate Cycle¶
Tastypie uses a “hydrate” cycle to take serializated data from the client and turn it into something the data model can use. This is the reverse process from the dehydrate cycle. In fact, by default, Tastypie’s serialized data should be “round-trip-able”, meaning the data that comes out should be able to be fed back in & result in the same original data model. This usually means taking a dictionary of simple data types & turning it into a complex data object.
Broadly speaking, this takes the recently-deserialized bundle.data dictionary & builds bundle.obj (but does NOT save it).
The cycle looks like:
- Put the data from the client into a Bundle instance, which is then passed through the various methods.
- If the hydrate method is present on the Resource, it is called & given the entire bundle.
- Then run through all fields on the Resource, look for a hydrate_<fieldname> method on the Resource. If it’s present, call it with the bundle.
- Finally after all other processing is done, while processing each field, let each field perform its own hydrate method on the bundle.
The goal of this cycle is to populate the bundle.obj data model with data suitable for saving/persistence. Again, with the exception of the alter_* methods (as hooks to manipulate the overall structure), this cycle controls how the data from the client is interpreted & placed on the data model.
hydrate¶
The hydrate method allows you to make initial changes to the bundle.obj. This includes things like prepopulating fields you don’t expose over the API, recalculating related data or mangling data.
Example:
class MyResource(ModelResource):
# The ``title`` field is already added to the class by ``ModelResource``
# and populated off ``Note.title``. We'll use that title to build a
# ``Note.slug`` as well.
class Meta:
queryset = Note.objects.all()
def hydrate(self, bundle):
# Don't change existing slugs.
# In reality, this would be better implemented at the ``Note.save``
# level, but is for demonstration.
if not bundle.obj.pk:
bundle.obj.slug = slugify(bundle.data['title'])
return bundle
This method should return a bundle, whether it modifies the existing one or creates a whole new one. You can even remove any/all data from the bundle.obj if you wish.
hydrate_FOO¶
Data from the client may not map directly onto the data model or might need augmentation. This hook lets you take that data & convert it.
Note
The FOO here is not literal. Instead, it is a placeholder that should be replaced with the fieldname in question.
A simple example:
class MyResource(ModelResource):
# The ``title`` field is already added to the class by ``ModelResource``
# and populated off ``Note.title``. But we want lowercase titles...
class Meta:
queryset = Note.objects.all()
def hydrate_title(self, bundle):
bundle.data['title'] = bundle.data['title'].lower()
return bundle
The return value is the bundle.
Per-field hydrate¶
Each field (even custom ApiField subclasses) has its own hydrate method. If it knows how to access data (say, given the attribute kwarg), it will attempt to take data from the bundle.data & assign it on the data model.
The return value is put in the bundle.obj attribute for that fieldname.
Reverse “Relationships”¶
Unlike Django’s ORM, Tastypie does not automatically create reverse relations. This is because there is substantial technical complexity involved, as well as perhaps unintentionally exposing related data in an incorrect way to the end user of the API.
However, it is still possible to create reverse relations. Instead of handing the ToOneField or ToManyField a class, pass them a string that represents the full path to the desired class. Implementing a reverse relationship looks like so:
# myapp/api/resources.py
from tastypie import fields
from tastypie.resources import ModelResource
from myapp.models import Note, Comment
class NoteResource(ModelResource):
comments = fields.ToManyField('myapp.api.resources.CommentResource', 'comments')
class Meta:
queryset = Note.objects.all()
class CommentResource(ModelResource):
note = fields.ToOneField(NoteResource, 'notes')
class Meta:
queryset = Comment.objects.all()
Warning
Unlike Django, you can’t use just the class name (i.e. 'CommentResource'), even if it’s in the same module. Tastypie (intentionally) lacks a construct like the AppCache which makes that sort of thing work in Django. Sorry.
Tastypie also supports self-referential relations. If you assume we added the appropriate self-referential ForeignKey to the Note model, implementing a similar relation in Tastypie would look like:
# myapp/api/resources.py
from tastypie import fields
from tastypie.resources import ModelResource
from myapp.models import Note
class NoteResource(ModelResource):
sub_notes = fields.ToManyField('self', 'notes')
class Meta:
queryset = Note.objects.all()
Resource Options (AKA Meta)¶
The inner Meta class allows for class-level configuration of how the Resource should behave. The following options are available:
serializer¶
Controls which serializer class the Resource should use. Default is tastypie.serializers.Serializer().
authentication¶
Controls which authentication class the Resource should use. Default is tastypie.authentication.Authentication().
authorization¶
Controls which authorization class the Resource should use. Default is tastypie.authorization.ReadOnlyAuthorization().
validation¶
Controls which validation class the Resource should use. Default is tastypie.validation.Validation().
paginator_class¶
Controls which paginator class the Resource should use. Default is tastypie.paginator.Paginator.
Note
This is different than the other options in that you supply a class rather than an instance. This is done because the Paginator has some per-request initialization options.
cache¶
Controls which cache class the Resource should use. Default is tastypie.cache.NoCache().
throttle¶
Controls which throttle class the Resource should use. Default is tastypie.throttle.BaseThrottle().
allowed_methods¶
Controls what list & detail REST methods the Resource should respond to. Default is None, which means delegate to the more specific list_allowed_methods & detail_allowed_methods options.
You may specify a list like ['get', 'post', 'put', 'delete', 'patch'] as a shortcut to prevent having to specify the other options.
list_allowed_methods¶
Controls what list REST methods the Resource should respond to. Default is ['get', 'post', 'put', 'delete', 'patch'].
detail_allowed_methods¶
Controls what detail REST methods the Resource should respond to. Default is ['get', 'post', 'put', 'delete', 'patch'].
limit¶
Controls how many results the Resource will show at a time. Default is either the API_LIMIT_PER_PAGE setting (if provided) or 20 if not specified.
max_limit¶
Controls the maximum number of results the Resource will show at a time. If the user-specified limit is higher than this, it will be capped to this limit. Set to 0 or None to allow unlimited results.
api_name¶
An override for the Resource to use when generating resource URLs. Default is None.
resource_name¶
An override for the Resource to use when generating resource URLs. Default is None.
If not provided, the Resource or ModelResource will attempt to name itself. This means a lowercase version of the classname preceding the word Resource if present (i.e. SampleContentResource would become samplecontent).
default_format¶
Specifies the default serialization format the Resource should use if one is not requested (usually by the Accept header or format GET parameter). Default is application/json.
filtering¶
Provides a list of fields that the Resource will accept client filtering on. Default is {}.
Keys should be the fieldnames as strings while values should be a list of accepted filter types.
ordering¶
Specifies the what fields the Resource should should allow ordering on. Default is [].
Values should be the fieldnames as strings. When provided to the Resource by the order_by GET parameter, you can specify either the fieldname (ascending order) or -fieldname (descending order).
object_class¶
Provides the Resource with the object that serves as the data source. Default is None.
In the case of ModelResource, this is automatically populated by the queryset option and is the model class.
queryset¶
Provides the Resource with the set of Django models to respond with. Default is None.
Unused by Resource but present for consistency.
Warning
If you place any callables in this, they’ll only be evaluated once (when the Meta class is instantiated). This especially affects things that are date/time related. Please see the :ref:cookbook for a way around this.
fields¶
Controls what introspected fields the Resource should include. A whitelist of fields. Default is [].
excludes¶
Controls what introspected fields the Resource should NOT include. A blacklist of fields. Default is [].
include_resource_uri¶
Specifies if the Resource should include an extra field that displays the detail URL (within the api) for that resource. Default is True.
include_absolute_url¶
Specifies if the Resource should include an extra field that displays the get_absolute_url for that object (on the site proper). Default is False.
always_return_data¶
Specifies all HTTP methods (except DELETE) should return a serialized form of the data. Default is False.
If False, HttpNoContent (204) is returned on PUT with an empty body & a Location header of where to request the full resource.
If True, HttpResponse (200) is returned on POST/PUT with a body containing all the data in a serialized form.
collection_name¶
Specifies the collection of objects returned in the GET list will be named. Default is objects.
detail_uri_name¶
Specifies the name for the regex group that matches on detail views. Defaults to pk.
Basic Filtering¶
ModelResource provides a basic Django ORM filter interface. Simply list the resource fields which you’d like to filter on and the allowed expression in a filtering property of your resource’s Meta class:
from tastypie.constants import ALL, ALL_WITH_RELATIONS
class MyResource(ModelResource):
class Meta:
filtering = {
"slug": ('exact', 'startswith',),
"title": ALL,
}
Valid filtering values are: Django ORM filters (e.g. startswith, exact, lte, etc. or the ALL or ALL_WITH_RELATIONS constants defined in tastypie.constants.
These filters will be extracted from URL query strings using the same double-underscore syntax as the Django ORM:
/api/v1/myresource/?slug=myslug
/api/v1/myresource/?slug__startswith=test
Advanced Filtering¶
If you need to filter things other than ORM resources or wish to apply additional constraints (e.g. text filtering using django-haystack <http://haystacksearch.org> rather than simple database queries) your Resource may define a custom build_filters() method which allows you to filter the queryset before processing a request:
from haystack.query import SearchQuerySet
class MyResource(Resource):
def build_filters(self, filters=None):
if filters is None:
filters = {}
orm_filters = super(MyResource, self).build_filters(filters)
if "q" in filters:
sqs = SearchQuerySet().auto_query(filters['q'])
orm_filters["pk__in"] = [i.pk for i in sqs]
return orm_filters
Using PUT/DELETE/PATCH In Unsupported Places¶
Some places, like in certain browsers or hosts, don’t allow the PUT/DELETE/PATCH methods. In these environments, you can simulate those kinds of requests by providing an X-HTTP-Method-Override header. For example, to send a PATCH request over POST, you’d send a request like:
curl --dump-header - -H "Content-Type: application/json" -H "X-HTTP-Method-Override: PATCH" -X POST --data '{"title": "I Visited Grandma Today"}' http://localhost:8000/api/v1/entry/1/
Resource Methods¶
Handles the data, request dispatch and responding to requests.
Serialization/deserialization is handled “at the edges” (i.e. at the beginning/end of the request/response cycle) so that everything internally is Python data structures.
This class tries to be non-model specific, so it can be hooked up to other data sources, such as search results, files, other data, etc.
wrap_view¶
- Resource.wrap_view(self, view)¶
Wraps methods so they can be called in a more functional way as well as handling exceptions better.
Note that if BadRequest or an exception with a response attr are seen, there is special handling to either present a message back to the user or return the response traveling with the exception.
base_urls¶
- Resource.base_urls(self)¶
The standard URLs this Resource should respond to. These include the list, detail, schema & multiple endpoints by default.
Should return a list of individual URLconf lines (NOT wrapped in patterns).
override_urls¶
- Resource.override_urls(self)¶
Deprecated. Will be removed by v1.0.0. Please use Resource.prepend_urls instead.
prepend_urls¶
- Resource.prepend_urls(self)¶
A hook for adding your own URLs or matching before the default URLs. Useful for adding custom endpoints or overriding the built-in ones (from base_urls).
Should return a list of individual URLconf lines (NOT wrapped in patterns).
urls¶
- Resource.urls(self)¶
Property
The endpoints this Resource responds to. A combination of base_urls & override_urls.
Mostly a standard URLconf, this is suitable for either automatic use when registered with an Api class or for including directly in a URLconf should you choose to.
determine_format¶
- Resource.determine_format(self, request)¶
Used to determine the desired format.
Largely relies on tastypie.utils.mime.determine_format but here as a point of extension.
serialize¶
- Resource.serialize(self, request, data, format, options=None)¶
Given a request, data and a desired format, produces a serialized version suitable for transfer over the wire.
Mostly a hook, this uses the Serializer from Resource._meta.
deserialize¶
- Resource.deserialize(self, request, data, format='application/json')¶
Given a request, data and a format, deserializes the given data.
It relies on the request properly sending a CONTENT_TYPE header, falling back to application/json if not provided.
Mostly a hook, this uses the Serializer from Resource._meta.
alter_list_data_to_serialize¶
- Resource.alter_list_data_to_serialize(self, request, data)¶
A hook to alter list data just before it gets serialized & sent to the user.
Useful for restructuring/renaming aspects of the what’s going to be sent.
Should accommodate for a list of objects, generally also including meta data.
alter_detail_data_to_serialize¶
- Resource.alter_detail_data_to_serialize(self, request, data)¶
A hook to alter detail data just before it gets serialized & sent to the user.
Useful for restructuring/renaming aspects of the what’s going to be sent.
Should accommodate for receiving a single bundle of data.
alter_deserialized_list_data¶
- Resource.alter_deserialized_list_data(self, request, data)¶
A hook to alter list data just after it has been received from the user & gets deserialized.
Useful for altering the user data before any hydration is applied.
alter_deserialized_detail_data¶
- Resource.alter_deserialized_detail_data(self, request, data)¶
A hook to alter detail data just after it has been received from the user & gets deserialized.
Useful for altering the user data before any hydration is applied.
dispatch_list¶
- Resource.dispatch_list(self, request, **kwargs)¶
A view for handling the various HTTP methods (GET/POST/PUT/DELETE) over the entire list of resources.
Relies on Resource.dispatch for the heavy-lifting.
dispatch_detail¶
- Resource.dispatch_detail(self, request, **kwargs)¶
A view for handling the various HTTP methods (GET/POST/PUT/DELETE) on a single resource.
Relies on Resource.dispatch for the heavy-lifting.
dispatch¶
- Resource.dispatch(self, request_type, request, **kwargs)¶
Handles the common operations (allowed HTTP method, authentication, throttling, method lookup) surrounding most CRUD interactions.
remove_api_resource_names¶
- Resource.remove_api_resource_names(self, url_dict)¶
Given a dictionary of regex matches from a URLconf, removes api_name and/or resource_name if found.
This is useful for converting URLconf matches into something suitable for data lookup. For example:
Model.objects.filter(**self.remove_api_resource_names(matches))
method_check¶
- Resource.method_check(self, request, allowed=None)¶
Ensures that the HTTP method used on the request is allowed to be handled by the resource.
Takes an allowed parameter, which should be a list of lowercase HTTP methods to check against. Usually, this looks like:
# The most generic lookup.
self.method_check(request, self._meta.allowed_methods)
# A lookup against what's allowed for list-type methods.
self.method_check(request, self._meta.list_allowed_methods)
# A useful check when creating a new endpoint that only handles
# GET.
self.method_check(request, ['get'])
is_authorized¶
Handles checking of permissions to see if the user has authorization to GET, POST, PUT, or DELETE this resource. If object is provided, the authorization backend can apply additional row-level permissions checking.
is_authenticated¶
- Resource.is_authenticated(self, request)¶
Handles checking if the user is authenticated and dealing with unauthenticated users.
Mostly a hook, this uses class assigned to authentication from Resource._meta.
throttle_check¶
- Resource.throttle_check(self, request)¶
Handles checking if the user should be throttled.
Mostly a hook, this uses class assigned to throttle from Resource._meta.
log_throttled_access¶
- Resource.log_throttled_access(self, request)¶
Handles the recording of the user’s access for throttling purposes.
Mostly a hook, this uses class assigned to throttle from Resource._meta.
build_bundle¶
- Resource.build_bundle(self, obj=None, data=None, request=None)¶
Given either an object, a data dictionary or both, builds a Bundle for use throughout the dehydrate/hydrate cycle.
If no object is provided, an empty object from Resource._meta.object_class is created so that attempts to access bundle.obj do not fail.
build_filters¶
- Resource.build_filters(self, filters=None)¶
Allows for the filtering of applicable objects.
This needs to be implemented at the user level.
ModelResource includes a full working version specific to Django’s Models.
apply_sorting¶
- Resource.apply_sorting(self, obj_list, options=None)¶
Allows for the sorting of objects being returned.
This needs to be implemented at the user level.
ModelResource includes a full working version specific to Django’s Models.
get_bundle_detail_data¶
- Resource.get_bundle_detail_data(self, bundle)¶
Convenience method to return the detail_uri_name attribute off bundle.obj.
Usually just accesses bundle.obj.pk by default.
get_resource_uri¶
- Resource.get_resource_uri(self, bundle_or_obj=None, url_name='api_dispatch_list')¶
Handles generating a resource URI.
If the bundle_or_obj argument is not provided, it builds the URI for the list endpoint.
If the bundle_or_obj argument is provided, it builds the URI for the detail endpoint.
Return the generated URI. If that URI can not be reversed (not found in the URLconf), it will return an empty string.
resource_uri_kwargs¶
- Resource.resource_uri_kwargs(self, bundle_or_obj=None)¶
Handles generating a resource URI.
If the bundle_or_obj argument is not provided, it builds the URI for the list endpoint.
If the bundle_or_obj argument is provided, it builds the URI for the detail endpoint.
Return the generated URI. If that URI can not be reversed (not found in the URLconf), it will return None.
detail_uri_kwargs¶
- Resource.detail_uri_kwargs(self, bundle_or_obj)¶
This needs to be implemented at the user level.
Given a Bundle or an object, it returns the extra kwargs needed to generate a detail URI.
ModelResource includes a full working version specific to Django’s Models.
get_via_uri¶
- Resource.get_via_uri(self, uri, request=None)¶
This pulls apart the salient bits of the URI and populates the resource via a obj_get.
Optionally accepts a request.
If you need custom behavior based on other portions of the URI, simply override this method.
full_dehydrate¶
- Resource.full_dehydrate(self, bundle, for_list=False)¶
Given a bundle with an object instance, extract the information from it to populate the resource.
The for_list flag is used to control which fields are excluded by the use_in attribute.
dehydrate¶
- Resource.dehydrate(self, bundle)¶
A hook to allow a final manipulation of data once all fields/methods have built out the dehydrated data.
Useful if you need to access more than one dehydrated field or want to annotate on additional data.
Must return the modified bundle.
full_hydrate¶
- Resource.full_hydrate(self, bundle)¶
Given a populated bundle, distill it and turn it back into a full-fledged object instance.
hydrate¶
- Resource.hydrate(self, bundle)¶
A hook to allow a final manipulation of data once all fields/methods have built out the hydrated data.
Useful if you need to access more than one hydrated field or want to annotate on additional data.
Must return the modified bundle.
build_schema¶
- Resource.build_schema(self)¶
Returns a dictionary of all the fields on the resource and some properties about those fields.
Used by the schema/ endpoint to describe what will be available.
dehydrate_resource_uri¶
- Resource.dehydrate_resource_uri(self, bundle)¶
For the automatically included resource_uri field, dehydrate the URI for the given bundle.
Returns empty string if no URI can be generated.
generate_cache_key¶
- Resource.generate_cache_key(self, *args, **kwargs)¶
Creates a unique-enough cache key.
This is based off the current api_name/resource_name/args/kwargs.
get_object_list¶
- Resource.get_object_list(self, request)¶
A hook to allow making returning the list of available objects.
This needs to be implemented at the user level.
ModelResource includes a full working version specific to Django’s Models.
apply_authorization_limits¶
Allows the Authorization class to further limit the object list. Also a hook to customize per Resource.
Calls Authorization.apply_limits if available.
can_update¶
- Resource.can_update(self)¶
Checks to ensure put is within allowed_methods.
Used when hydrating related data.
apply_filters¶
- Resource.apply_filters(self, request, applicable_filters)¶
A hook to alter how the filters are applied to the object list.
This needs to be implemented at the user level.
ModelResource includes a full working version specific to Django’s Models.
obj_get_list¶
- Resource.obj_get_list(self, bundle, **kwargs)¶
Fetches the list of objects available on the resource.
This needs to be implemented at the user level.
ModelResource includes a full working version specific to Django’s Models.
cached_obj_get_list¶
- Resource.cached_obj_get_list(self, bundle, **kwargs)¶
A version of obj_get_list that uses the cache as a means to get commonly-accessed data faster.
obj_get¶
- Resource.obj_get(self, bundle, **kwargs)¶
Fetches an individual object on the resource.
This needs to be implemented at the user level. If the object can not be found, this should raise a NotFound exception.
ModelResource includes a full working version specific to Django’s Models.
cached_obj_get¶
- Resource.cached_obj_get(self, bundle, **kwargs)¶
A version of obj_get that uses the cache as a means to get commonly-accessed data faster.
obj_create¶
- Resource.obj_create(self, bundle, **kwargs)¶
Creates a new object based on the provided data.
This needs to be implemented at the user level.
ModelResource includes a full working version specific to Django’s Models.
lookup_kwargs_with_identifiers¶
- Resource.lookup_kwargs_with_identifiers(self, bundle, kwargs)¶
Kwargs here represent uri identifiers. Ex: /repos/<user_id>/<repo_name>/ We need to turn those identifiers into Python objects for generating lookup parameters that can find them in the DB.
obj_update¶
- Resource.obj_update(self, bundle, **kwargs)¶
Updates an existing object (or creates a new object) based on the provided data.
This needs to be implemented at the user level.
ModelResource includes a full working version specific to Django’s Models.
obj_delete_list¶
- Resource.obj_delete_list(self, bundle, **kwargs)¶
Deletes an entire list of objects.
This needs to be implemented at the user level.
ModelResource includes a full working version specific to Django’s Models.
obj_delete_list_for_update¶
- Resource.obj_delete_list_for_update(self, bundle, **kwargs)¶
Deletes an entire list of objects, specific to PUT list.
This needs to be implemented at the user level.
ModelResource includes a full working version specific to Django’s Models.
obj_delete¶
- Resource.obj_delete(self, bundle, **kwargs)¶
Deletes a single object.
This needs to be implemented at the user level.
ModelResource includes a full working version specific to Django’s Models.
create_response¶
- Resource.create_response(self, request, data, response_class=HttpResponse, **response_kwargs)¶
Extracts the common “which-format/serialize/return-response” cycle.
Mostly a useful shortcut/hook.
is_valid¶
- Resource.is_valid(self, bundle)¶
Handles checking if the data provided by the user is valid.
Mostly a hook, this uses class assigned to validation from Resource._meta.
If validation fails, an error is raised with the error messages serialized inside it.
rollback¶
- Resource.rollback(self, bundles)¶
Given the list of bundles, delete all objects pertaining to those bundles.
This needs to be implemented at the user level. No exceptions should be raised if possible.
ModelResource includes a full working version specific to Django’s Models.
get_list¶
- Resource.get_list(self, request, **kwargs)¶
Returns a serialized list of resources.
Calls obj_get_list to provide the data, then handles that result set and serializes it.
Should return a HttpResponse (200 OK).
get_detail¶
- Resource.get_detail(self, request, **kwargs)¶
Returns a single serialized resource.
Calls cached_obj_get/obj_get to provide the data, then handles that result set and serializes it.
Should return a HttpResponse (200 OK).
put_list¶
- Resource.put_list(self, request, **kwargs)¶
Replaces a collection of resources with another collection.
Calls delete_list to clear out the collection then obj_create with the provided the data to create the new collection.
Return HttpNoContent (204 No Content) if Meta.always_return_data = False (default).
Return HttpAccepted (202 Accepted) if Meta.always_return_data = True.
put_detail¶
- Resource.put_detail(self, request, **kwargs)¶
Either updates an existing resource or creates a new one with the provided data.
Calls obj_update with the provided data first, but falls back to obj_create if the object does not already exist.
If a new resource is created, return HttpCreated (201 Created). If Meta.always_return_data = True, there will be a populated body of serialized data.
If an existing resource is modified and Meta.always_return_data = False (default), return HttpNoContent (204 No Content). If an existing resource is modified and Meta.always_return_data = True, return HttpAccepted (202 Accepted).
post_list¶
- Resource.post_list(self, request, **kwargs)¶
Creates a new resource/object with the provided data.
Calls obj_create with the provided data and returns a response with the new resource’s location.
If a new resource is created, return HttpCreated (201 Created). If Meta.always_return_data = True, there will be a populated body of serialized data.
post_detail¶
- Resource.post_detail(self, request, **kwargs)¶
Creates a new subcollection of the resource under a resource.
This is not implemented by default because most people’s data models aren’t self-referential.
If a new resource is created, return HttpCreated (201 Created).
delete_list¶
- Resource.delete_list(self, request, **kwargs)¶
Destroys a collection of resources/objects.
Calls obj_delete_list.
If the resources are deleted, return HttpNoContent (204 No Content).
delete_detail¶
- Resource.delete_detail(self, request, **kwargs)¶
Destroys a single resource/object.
Calls obj_delete.
If the resource is deleted, return HttpNoContent (204 No Content). If the resource did not exist, return HttpNotFound (404 Not Found).
patch_list¶
- Resource.patch_list(self, request, **kwargs)¶
Updates a collection in-place.
The exact behavior of PATCH to a list resource is still the matter of some debate in REST circles, and the PATCH RFC isn’t standard. So the behavior this method implements (described below) is something of a stab in the dark. It’s mostly cribbed from GData, with a smattering of ActiveResource-isms and maybe even an original idea or two.
The PATCH format is one that’s similar to the response returned from a GET on a list resource:
{
"objects": [{object}, {object}, ...],
"deleted_objects": ["URI", "URI", "URI", ...],
}
For each object in objects:
- If the dict does not have a resource_uri key then the item is considered “new” and is handled like a POST to the resource list.
- If the dict has a resource_uri key and the resource_uri refers to an existing resource then the item is a update; it’s treated like a PATCH to the corresponding resource detail.
- If the dict has a resource_uri but the resource doesn’t exist, then this is considered to be a create-via-PUT.
Each entry in deleted_objects referes to a resource URI of an existing resource to be deleted; each is handled like a DELETE to the relevent resource.
In any case:
- If there’s a resource URI it must refer to a resource of this type. It’s an error to include a URI of a different resource.
- PATCH is all or nothing. If a single sub-operation fails, the entire request will fail and all resources will be rolled back.
- For PATCH to work, you must have put in your detail_allowed_methods setting.
- To delete objects via deleted_objects in a PATCH request you must have delete in your detail_allowed_methods setting.
patch_detail¶
- Resource.patch_detail(self, request, **kwargs)¶
Updates a resource in-place.
Calls obj_update.
If the resource is updated, return HttpAccepted (202 Accepted). If the resource did not exist, return HttpNotFound (404 Not Found).
ModelResource Methods¶
A subclass of Resource designed to work with Django’s Models.
This class will introspect a given Model and build a field list based on the fields found on the model (excluding relational fields).
Given that it is aware of Django’s ORM, it also handles the CRUD data operations of the resource.
should_skip_field¶
- ModelResource.should_skip_field(cls, field)¶
Class method
Given a Django model field, return if it should be included in the contributed ApiFields.
api_field_from_django_field¶
- ModelResource.api_field_from_django_field(cls, f, default=CharField)¶
Class method
Returns the field type that would likely be associated with each Django type.
get_fields¶
- ModelResource.get_fields(cls, fields=None, excludes=None)¶
Class method
Given any explicit fields to include and fields to exclude, add additional fields based on the associated model.
check_filtering¶
- ModelResource.check_filtering(self, field_name, filter_type='exact', filter_bits=None)¶
Given a field name, a optional filter type and an optional list of additional relations, determine if a field can be filtered on.
If a filter does not meet the needed conditions, it should raise an InvalidFilterError.
If the filter meets the conditions, a list of attribute names (not field names) will be returned.
build_filters¶
- ModelResource.build_filters(self, filters=None)¶
Given a dictionary of filters, create the necessary ORM-level filters.
Keys should be resource fields, NOT model fields.
Valid values are either a list of Django filter types (i.e. ['startswith', 'exact', 'lte']), the ALL constant or the ALL_WITH_RELATIONS constant.
At the declarative level:
filtering = {
'resource_field_name': ['exact', 'startswith', 'endswith', 'contains'],
'resource_field_name_2': ['exact', 'gt', 'gte', 'lt', 'lte', 'range'],
'resource_field_name_3': ALL,
'resource_field_name_4': ALL_WITH_RELATIONS,
...
}
Accepts the filters as a dict. None by default, meaning no filters.
apply_sorting¶
- ModelResource.apply_sorting(self, obj_list, options=None)¶
Given a dictionary of options, apply some ORM-level sorting to the provided QuerySet.
Looks for the order_by key and handles either ascending (just the field name) or descending (the field name with a - in front).
The field name should be the resource field, NOT model field.
apply_filters¶
- ModelResource.apply_filters(self, request, applicable_filters)¶
An ORM-specific implementation of apply_filters.
The default simply applies the applicable_filters as **kwargs, but should make it possible to do more advanced things.
get_object_list¶
- ModelResource.get_object_list(self, request)¶
A ORM-specific implementation of get_object_list.
Returns a QuerySet that may have been limited by other overrides.
obj_get_list¶
- ModelResource.obj_get_list(self, filters=None, **kwargs)¶
A ORM-specific implementation of obj_get_list.
Takes an optional filters dictionary, which can be used to narrow the query.
obj_get¶
- ModelResource.obj_get(self, **kwargs)¶
A ORM-specific implementation of obj_get.
Takes optional kwargs, which are used to narrow the query to find the instance.
obj_create¶
- ModelResource.obj_create(self, bundle, **kwargs)¶
A ORM-specific implementation of obj_create.
obj_update¶
- ModelResource.obj_update(self, bundle, **kwargs)¶
A ORM-specific implementation of obj_update.
obj_delete_list¶
- ModelResource.obj_delete_list(self, **kwargs)¶
A ORM-specific implementation of obj_delete_list.
Takes optional kwargs, which can be used to narrow the query.
obj_delete_list_for_update¶
- ModelResource.obj_delete_list_for_update(self, **kwargs)¶
A ORM-specific implementation of obj_delete_list_for_update.
Takes optional kwargs, which can be used to narrow the query.
obj_delete¶
- ModelResource.obj_delete(self, **kwargs)¶
A ORM-specific implementation of obj_delete.
Takes optional kwargs, which are used to narrow the query to find the instance.
rollback¶
- ModelResource.rollback(self, bundles)¶
A ORM-specific implementation of rollback.
Given the list of bundles, delete all models pertaining to those bundles.
save_m2m¶
- ModelResource.save_m2m(self, bundle)¶
Handles the saving of related M2M data.
Due to the way Django works, the M2M data must be handled after the main instance, which is why this isn’t a part of the main save bits.
Currently slightly inefficient in that it will clear out the whole relation and recreate the related data as needed.
Bundles¶
What Are Bundles?¶
Bundles are a small abstraction that allow Tastypie to pass data between resources. This allows us not to depend on passing request to every single method (especially in places where this would be overkill). It also allows resources to work with data coming into the application paired together with an unsaved instance of the object in question. Finally, it aids in keeping Tastypie more thread-safe.
Think of it as package of user data & an object instance (either of which are optionally present).
Attributes¶
All data within a bundle can be optional, especially depending on how it’s being used. If you write custom code using Bundle, make sure appropriate guards are in place.
obj¶
Either a Python object or None.
Usually a Django model, though it may/may not have been saved already.
data¶
Always a plain Python dictionary of data. If not provided, it will be empty.
request¶
Either the Django request that’s part of the issued request or an empty HttpRequest if it wasn’t provided.
Api¶
In terms of a REST-style architecture, the “api” is a collection of resources. In Tastypie, the Api gathers together the Resources & provides a nice way to use them as a set. It handles many of the URLconf details for you, provides a helpful “top-level” view to show what endpoints are available & some extra URL resolution juice.
Quick Start¶
A sample api definition might look something like (usually located in a URLconf):
from tastypie.api import Api
from myapp.api.resources import UserResource, EntryResource
v1_api = Api(api_name='v1')
v1_api.register(UserResource())
v1_api.register(EntryResource())
# Standard bits...
urlpatterns = patterns('',
(r'^api/', include(v1_api.urls)),
)
Api Methods¶
Implements a registry to tie together the various resources that make up an API.
Especially useful for navigation, HATEOAS and for providing multiple versions of your API.
Optionally supplying api_name allows you to name the API. Generally, this is done with version numbers (i.e. v1, v2, etc.) but can be named any string.
register¶
- Api.register(self, resource, canonical=True):
Registers an instance of a Resource subclass with the API.
Optionally accept a canonical argument, which indicates that the resource being registered is the canonical variant. Defaults to True.
canonical_resource_for¶
- Api.canonical_resource_for(self, resource_name):
Returns the canonical resource for a given resource_name.
override_urls¶
- Api.override_urls(self):
Deprecated. Will be removed by v1.0.0. Please use Api.prepend_urls instead.
prepend_urls¶
- Api.prepend_urls(self):
A hook for adding your own URLs or matching before the default URLs. Useful for adding custom endpoints or overriding the built-in ones.
Should return a list of individual URLconf lines (NOT wrapped in patterns).
urls¶
- Api.urls(self):
Property
Provides URLconf details for the Api and all registered Resources beneath it.
top_level¶
- Api.top_level(self, request, api_name=None):
A view that returns a serialized list of all resources registers to the Api. Useful for discovery.
Resource Fields¶
When designing an API, an important component is defining the representation of the data you’re presenting. Like Django models, you can control the representation of a Resource using fields. There are a variety of fields for various types of data.
Quick Start¶
For the impatient:
from tastypie import fields, utils
from tastypie.resources import Resource
from myapp.api.resources import ProfileResource, NoteResource
class PersonResource(Resource):
name = fields.CharField(attribute='name')
age = fields.IntegerField(attribute='years_old', null=True)
created = fields.DateTimeField(readonly=True, help_text='When the person was created', default=utils.now)
is_active = fields.BooleanField(default=True)
profile = fields.ToOneField(ProfileResource, 'profile')
notes = fields.ToManyField(NoteResource, 'notes', full=True)
Standard Data Fields¶
All standard data fields have a common base class ApiField which handles the basic implementation details.
Note
You should not use the ApiField class directly. Please use one of the subclasses that is more correct for your data.
Common Field Options¶
All ApiField objects accept the following options.
attribute¶
- ApiField.attribute¶
A string naming an instance attribute of the object wrapped by the Resource. The attribute will be accessed during the dehydrate or or written during the hydrate.
Defaults to None, meaning data will be manually accessed.
default¶
- ApiField.default¶
Provides default data when the object being dehydrated/hydrated has no data on the field.
Defaults to tastypie.fields.NOT_PROVIDED.
null¶
- ApiField.null¶
Indicates whether or not a None is allowable data on the field. Defaults to False.
blank¶
- ApiField.blank¶
Indicates whether or not data may be omitted on the field. Defaults to False.
This is useful for allowing the user to omit data that you can populate based on the request, such as the user or site to associate a record with.
readonly¶
- ApiField.readonly¶
Indicates whether the field is used during the hydrate or not. Defaults to False.
Field Types¶
DateField¶
A date field.
DateTimeField¶
A datetime field.
DecimalField¶
A decimal field.
DictField¶
A dictionary field.
FloatField¶
A floating point field.
IntegerField¶
An integer field.
Covers models.IntegerField, models.PositiveIntegerField, models.PositiveSmallIntegerField and models.SmallIntegerField.
ListField¶
A list field.
TimeField¶
A time field.
Relationship Fields¶
Provides access to data that is related within the database.
The RelatedField base class is not intended for direct use but provides functionality that ToOneField and ToManyField build upon.
The contents of this field actually point to another Resource, rather than the related object. This allows the field to represent its data in different ways.
The abstractions based around this are “leaky” in that, unlike the other fields provided by tastypie, these fields don’t handle arbitrary objects very well. The subclasses use Django’s ORM layer to make things go, though there is no ORM-specific code at this level.
Common Field Options¶
In addition to the common attributes for all ApiField, relationship fields accept the following.
full¶
- RelatedField.full¶
Indicates how the related Resource will appear post-dehydrate. If False, the related Resource will appear as a URL to the endpoint of that resource. If True, the result of the sub-resource’s dehydrate will be included in full. You can further control post-dehydrate behaviour when requesting a resource or a list of resources by setting full_list and full_detail.
full_list¶
- RelatedField.full_list¶
Indicates how the related Resource will appear post-dehydrate when requesting a list of resources. The value is one of True, False or a callable that accepts a bundle and returns True or False. If False, the related Resource will appear as a URL to the endpoint of that resource if accessing a list of resources. If True and full is also True, the result of thesub-resource’s dehydrate will be included in full. Default is True
full_detail¶
- RelatedField.full_detail¶
Indicates how the related Resource will appear post-dehydrate when requesting a single resource. The value is one of True, False or a callable that accepts a bundle and returns True or False. If False, the related Resource will appear as a URL to the endpoint of that resource if accessing a specific resources. If True and full is also True, the result of thesub-resource’s dehydrate will be included in full. Default is True
Field Types¶
ToOneField¶
Provides access to related data via foreign key.
This subclass requires Django’s ORM layer to work properly.
OneToOneField¶
An alias to ToOneField for those who prefer to mirror django.db.models.
ForeignKey¶
An alias to ToOneField for those who prefer to mirror django.db.models.
ToManyField¶
Provides access to related data via a join table.
This subclass requires Django’s ORM layer to work properly.
This field also has special behavior when dealing with attribute in that it can take a callable. For instance, if you need to filter the reverse relation, you can do something like:
subjects = fields.ToManyField(SubjectResource, attribute=lambda bundle: Subject.objects.filter(notes=bundle.obj, name__startswith='Personal'))
Note that the hydrate portions of this field are quite different than any other field. hydrate_m2m actually handles the data and relations. This is due to the way Django implements M2M relationships.
ManyToManyField¶
An alias to ToManyField for those who prefer to mirror django.db.models.
OneToManyField¶
An alias to ToManyField for those who prefer to mirror django.db.models.
Caching¶
When adding an API to your site, it’s important to understand that most consumers of the API will not be people, but instead machines. This means that the traditional “fetch-read-click” cycle is no longer measured in minutes but in seconds or milliseconds.
As such, caching is a very important part of the deployment of your API. Tastypie ships with two classes to make working with caching easier. These caches store at the object level, reducing access time on the database.
However, it’s worth noting that these do NOT cache serialized representations. For heavy traffic, we’d encourage the use of a caching proxy, especially Varnish, as it shines under this kind of usage. It’s far faster than Django views and already neatly handles most situations.
The first section below demonstrates how to cache at the Django level, reducing the amount of work required to satisfy a request. In many cases your API serves web browsers or is behind by a caching proxy such as Varnish and it is possible to set HTTP Cache-Control headers to avoid issuing a request to your application at all. This is discussed in the HTTP Cache-Control section below.
Usage¶
Using these classes is simple. Simply provide them (or your own class) as a Meta option to the Resource in question. For example:
from django.contrib.auth.models import User
from tastypie.cache import SimpleCache
from tastypie.resources import ModelResource
class UserResource(ModelResource):
class Meta:
queryset = User.objects.all()
resource_name = 'auth/user'
excludes = ['email', 'password', 'is_superuser']
# Add it here.
cache = SimpleCache(timeout=10)
Caching Options¶
Tastypie ships with the following Cache classes:
NoCache¶
The no-op cache option, this does no caching but serves as an api-compatible plug. Very useful for development.
SimpleCache¶
This option does basic object caching, attempting to find the object in the cache & writing the object to the cache. It uses Django’s current CACHE_BACKEND to store cached data. The constructor receive a timeout parameter to control per-resource the default timeout for the cache.
Implementing Your Own Cache¶
Implementing your own Cache class is as simple as subclassing NoCache and overriding the get & set methods. For example, a json-backed cache might look like:
import json
from django.conf import settings
from tastypie.cache import NoCache
class JSONCache(NoCache):
def _load(self):
data_file = open(settings.TASTYPIE_JSON_CACHE, 'r')
return json.load(data_file)
def _save(self, data):
data_file = open(settings.TASTYPIE_JSON_CACHE, 'w')
return json.dump(data, data_file)
def get(self, key):
data = self._load()
return data.get(key, None)
def set(self, key, value, timeout=60):
data = self._load()
data[key] = value
self._save(data)
Note that this is NOT necessarily an optimal solution, but is simply demonstrating how one might go about implementing your own Cache.
HTTP Cache-Control¶
The HTTP protocol defines a Cache-Control header, which can be used to tell clients and intermediaries who is allowed to cache a response and for how long. Mark Nottingham has a general caching introduction and the Django cache documentation describes how to set caching-related headers in your code. The range of possible options is beyond the scope of this documentation, but it’s important to know that, by default, Tastypie will prevent responses from being cached to ensure that clients always receive current information.
To override the default no-cache response, your Resource should ensure that your cache class implements cache_control. The default SimpleCache does this by default. It uses the timeout passed to the initialization as the max-age and s-maxage. By default, it does not claim to know if the results should be public or privately cached but this can be changed by passing either a public=True or a private=True to the initialization of the SimpleClass.
Behind the scenes, the return value from the cache_control method is passed to the cache_control helper provided by Django. If you wish to add your own methods to it, you can do so by overloading the cache_control method and modifying the dictionary it returns.:
from tastypie.cache import SimpleCache
class NoTransformCache(SimpleCache):
def cache_control(self):
control = super(NoTransformCache, self).cache_control()
control.update({"no_transform": True})
return control
HTTP Vary¶
The HTTP protocol defines a Vary header, which can be used to tell clients and intermediaries on what headers your response varies. This allows clients to store a correct response for each type. By default, Tastypie will send the Vary: Accept header so that a seperate response is cached for each Content-Type. However, if you wish to change this, simply pass a list to the varies kwarg of any Cache class.
It is important to note that if a list is passed, Tastypie not automatically include the Vary: Accept and you should include it as a member of your list.:
class ExampleResource(Resource):
class Meta:
cache = SimpleCache(varies=["Accept", "Cookie"])
Validation¶
Validation allows you to ensure that the data being submitted by the user is appropriate for storage. This can range from simple type checking on up to complex validation that compares different fields together.
If the data is valid, an empty dictionary is returned and processing continues as normal. If the data is invalid, a dictionary of error messages (keys being the field names, values being a list of error messages) is immediately returned to the user, serialized in the format they requested.
Usage¶
Using these classes is simple. Simply provide them (or your own class) as a Meta option to the Resource in question. For example:
from django.contrib.auth.models import User
from tastypie.validation import Validation
from tastypie.resources import ModelResource
class UserResource(ModelResource):
class Meta:
queryset = User.objects.all()
resource_name = 'auth/user'
excludes = ['email', 'password', 'is_superuser']
# Add it here.
validation = Validation()
Validation Options¶
Tastypie ships with the following Validation classes:
Validation¶
The no-op validation option, the data submitted is always considered to be valid.
This is the default class hooked up to Resource/ModelResource.
FormValidation¶
A more complex form of validation, this class accepts a form_class argument to its constructor. You supply a Django Form (or ModelForm, though save will never get called) and Tastypie will verify the data in the Bundle against the form.
This class DOES NOT alter the data sent, only verifies it. If you want to alter the data, please use the CleanedDataFormValidation class instead.
Warning
Data in the bundle must line up with the fieldnames in the Form. If they do not, you’ll need to either munge the data or change your form.
Usage looks like:
from django import forms
class NoteForm(forms.Form):
title = forms.CharField(max_length=100)
slug = forms.CharField(max_length=50)
content = forms.CharField(required=False, widget=forms.Textarea)
is_active = forms.BooleanField()
form = FormValidation(form_class=NoteForm)
CleanedDataFormValidation¶
Similar to the FormValidation class, this uses a Django Form to handle validation. However, it will use the form.cleaned_data to replace the bundle data sent by user! Usage is identical to FormValidation.
Implementing Your Own Validation¶
Implementing your own Validation classes is a simple process. The constructor can take whatever **kwargs it needs (if any). The only other method to implement is the is_valid method:
from tastypie.validation import Validation
class AwesomeValidation(Validation):
def is_valid(self, bundle, request=None):
if not bundle.data:
return {'__all__': 'Not quite what I had in mind.'}
errors = {}
for key, value in bundle.data.items():
if not isinstance(value, basestring):
continue
if not 'awesome' in value:
errors[key] = ['NOT ENOUGH AWESOME. NEEDS MORE.']
return errors
Under this validation, every field that’s a string is checked for the word ‘awesome’. If it’s not in the string, it’s an error.
Authentication¶
Authentication is the component needed to verify who a certain user is and to validate their access to the API.
Authentication answers the question “Who is this person?” This usually involves requiring credentials, such as an API key or username/password or oAuth tokens.
Usage¶
Using these classes is simple. Simply provide them (or your own class) as a Meta option to the Resource in question. For example:
from django.contrib.auth.models import User
from tastypie.authentication import BasicAuthentication
from tastypie.resources import ModelResource
class UserResource(ModelResource):
class Meta:
queryset = User.objects.all()
resource_name = 'auth/user'
excludes = ['email', 'password', 'is_superuser']
# Add it here.
authentication = BasicAuthentication()
Authentication Options¶
Tastypie ships with the following Authentication classes:
Authentication¶
The no-op authentication option, the client is always allowed through. Very useful for development and read-only APIs.
BasicAuthentication¶
This authentication scheme uses HTTP Basic Auth to check a user’s credentials. The username is their django.contrib.auth.models.User username (assuming it is present) and their password should also correspond to that entry.
Warning
If you’re using Apache & mod_wsgi, you will need to enable WSGIPassAuthorization On. See this post for details.
ApiKeyAuthentication¶
As an alternative to requiring sensitive data like a password, the ApiKeyAuthentication allows you to collect just username & a machine-generated api key. Tastypie ships with a special Model just for this purpose, so you’ll need to ensure tastypie is in INSTALLED_APPS and that the model’s database tables have been created (e.g. via django-admin.py syncdb).
To use this mechanism, the end user can either specify an Authorization header or pass the username/api_key combination as GET/POST parameters. Examples:
# As a header
# Format is ``Authorization: ApiKey <username>:<api_key>
Authorization: ApiKey daniel:204db7bcfafb2deb7506b89eb3b9b715b09905c8
# As GET params
http://127.0.0.1:8000/api/v1/entries/?username=daniel&api_key=204db7bcfafb2deb7506b89eb3b9b715b09905c8
Tastypie includes a signal function you can use to auto-create ApiKey objects. Hooking it up looks like:
from django.contrib.auth.models import User
from django.db import models
from tastypie.models import create_api_key
models.signals.post_save.connect(create_api_key, sender=User)
Warning
If you’re using Apache & mod_wsgi, you will need to enable WSGIPassAuthorization On, otherwise mod_wsgi strips out the Authorization header. See this post for details (even though it only mentions Basic auth).
Note
In some cases it may be useful to make the ApiKey model an abstract base class. To enable this, set settings.TASTYPIE_ABSTRACT_APIKEY to True. See the documentation for this setting for more information.
SessionAuthentication¶
This authentication scheme uses the built-in Django sessions to check if a user is logged. This is typically useful when used by Javascript on the same site as the API is hosted on.
It requires that the user has logged in & has an active session. They also must have a valid CSRF token.
DigestAuthentication¶
This authentication scheme uses HTTP Digest Auth to check a user’s credentials. The username is their django.contrib.auth.models.User username (assuming it is present) and their password should be their machine-generated api key. As with ApiKeyAuthentication, tastypie should be included in INSTALLED_APPS.
Warning
If you’re using Apache & mod_wsgi, you will need to enable WSGIPassAuthorization On. See this post for details (even though it only mentions Basic auth).
OAuthAuthentication¶
Handles OAuth, which checks a user’s credentials against a separate service. Currently verifies against OAuth 1.0a services.
This does NOT provide OAuth authentication in your API, strictly consumption.
Warning
If you’re used to in-browser OAuth flow (click a “Sign In” button, get redirected, login on remote service, get redirected back), this isn’t the same. Most prominently, expecting that would cause API clients to have to use tools like mechanize to fill in forms, which would be difficult.
This authentication expects that you’re already followed some sort of OAuth flow & that the credentials (Nonce/token/etc) are simply being passed to it. It merely checks that the credentials are valid. No requests are made to remote services as part of this authentication class.
MultiAuthentication¶
This authentication class actually wraps any number of other authentication classes, attempting each until successfully authenticating. For example:
from django.contrib.auth.models import User
from tastypie.authentication import BasicAuthentication, ApiKeyAuthentication, MultiAuthentication
from tastypie.authorization import DjangoAuthorization
from tastypie.resources import ModelResource
class UserResource(ModelResource):
class Meta:
queryset = User.objects.all()
resource_name = 'auth/user'
excludes = ['email', 'password', 'is_superuser']
authentication = MultiAuthentication(BasicAuthentication(), ApiKeyAuthentication())
authorization = DjangoAuthorization()
In the case of an authentication returning a customized HttpUnauthorized, MultiAuthentication defaults to the first returned one. Authentication schemes that need to control the response, such as the included BasicAuthentication and DigestAuthentication, should be placed first.
Implementing Your Own Authentication/Authorization¶
Implementing your own Authentication classes is a simple process. Authentication has two methods to override (one of which is optional but recommended to be customized):
from tastypie.authentication import Authentication
class SillyAuthentication(Authentication):
def is_authenticated(self, request, **kwargs):
if 'daniel' in request.user.username:
return True
return False
# Optional but recommended
def get_identifier(self, request):
return request.user.username
Under this scheme, only users with ‘daniel’ in their username will be allowed in.
Authorization¶
Authorization is the component needed to verify what someone can do with the resources within an API.
Authorization answers the question “Is permission granted for this user to take this action?” This usually involves checking permissions such as Create/Read/Update/Delete access, or putting limits on what data the user can access.
Usage¶
Using these classes is simple. Simply provide them (or your own class) as a Meta option to the Resource in question. For example:
from django.contrib.auth.models import User
from tastypie.authorization import DjangoAuthorization
from tastypie.resources import ModelResource
class UserResource(ModelResource):
class Meta:
queryset = User.objects.all()
resource_name = 'auth/user'
excludes = ['email', 'password', 'is_superuser']
# Add it here.
authorization = DjangoAuthorization()
Authorization Options¶
Tastypie ships with the following Authorization classes:
Authorization¶
The no-op authorization option, no permissions checks are performed.
Warning
This is a potentially dangerous option, as it means ANY recognized user can modify ANY data they encounter in the API. Be careful who you trust.
ReadOnlyAuthorization¶
This authorization class only permits reading data, regardless of what the Resource might think is allowed. This is the default Authorization class and the safe option.
DjangoAuthorization¶
The most advanced form of authorization, this checks the permission a user has granted to them (via django.contrib.auth.models.Permission). In conjunction with the admin, this is a very effective means of control.
The Authorization API¶
An Authorization-compatible class implements the following methods:
- read_list
- read_detail
- create_list
- create_detail
- update_list
- update_detail
- delete_list
- delete_detail
Each method takes two parameters, object_list & bundle.
object_list is the collection of objects being processed as part of the request. FILTERING & other restrictions to the set will have already been applied prior to this call.
bundle is the populated Bundle object for the request. You’ll likely frequently be accessing bundle.request.user, though raw access to the data can be helpful.
What you return from the method varies based on the type of method.
Return Values: The List Case¶
In the case of the *_list methods, you’ll want to filter the object_list & return only the objects the user has access to.
Returning an empty list simply won’t allow the action to be applied to any objects. However, they will not get a HTTP error status code.
If you’d rather they received an unauthorized status code, raising Unauthorized will return a HTTP 401.
Return Values: The Detail Case¶
In the case of the *_detail methods, you’ll have access to the object_list (so you know if a given object fits within the overall set), BUT you’ll want to be inspecting bundle.obj & either returning True if they should be allowed to continue or raising the Unauthorized exception if not.
Raising Unauthorized will cause a HTTP 401 error status code in the response.
Implementing Your Own Authorization¶
Implementing your own Authorization classes is a relatively simple process. Anything that is API-compatible is acceptable, only the method names matter to Tastypie.
An example implementation of a user only being able to “their” objects might look like:
from tastypie.authorization import Authorization
from tastypie.exceptions import Unauthorized
class UserObjectsOnlyAuthorization(Authorization):
def read_list(self, object_list, bundle):
# This assumes a ``QuerySet`` from ``ModelResource``.
return object_list.filter(user=bundle.request.user)
def read_detail(self, object_list, bundle):
# Is the requested object owned by the user?
return bundle.obj.user == bundle.request.user
def create_list(self, object_list, bundle):
# Assuming their auto-assigned to ``user``.
return object_list
def create_detail(self, object_list, bundle):
return bundle.obj.user == bundle.request.user
def update_list(self, object_list, bundle):
allowed = []
# Since they may not all be saved, iterate over them.
for obj in object_list:
if obj.user == bundle.request.user:
allowed.append(obj)
return allowed
def update_detail(self, object_list, bundle):
return bundle.obj.user == bundle.request.user
def delete_list(self, object_list, bundle):
# Sorry user, no deletes for you!
raise Unauthorized("Sorry, no deletes.")
def delete_detail(self, object_list, bundle):
raise Unauthorized("Sorry, no deletes.")
Serialization¶
Serialization can be one of the most contentious areas of an API. Everyone has their own requirements, their own preferred output format & the desire to have control over what is returned.
As a result, Tastypie ships with a serializer that tries to meet the basic needs of most use cases, and the flexibility to go outside of that when you need to.
Usage¶
Using this class is simple. It is the default option on all Resource classes unless otherwise specified. The following code is identical to the defaults but demonstrate how you could use your own serializer:
from django.contrib.auth.models import User
from tastypie.resources import ModelResource
from tastypie.serializers import Serializer
class UserResource(ModelResource):
class Meta:
queryset = User.objects.all()
resource_name = 'auth/user'
excludes = ['email', 'password', 'is_superuser']
# Add it here.
serializer = Serializer()
Configuring Allowed Formats¶
The default Serializer supports the following formats:
- json
- jsonp (Disabled by default)
- xml
- yaml
- html
- plist (see http://explorapp.com/biplist/)
Not everyone wants to install or support all the serialization options. If you would list to customize the list of supported formats for your entire site the TASTYPIE_DEFAULT_FORMATS setting allows you to set the default format list site-wide.
If you wish to change the format list for a specific resource, you can pass the list of supported formats using the formats= kwarg. For example, to provide only JSON & binary plist serialization:
from django.contrib.auth.models import User
from tastypie.resources import ModelResource
from tastypie.serializers import Serializer
class UserResource(ModelResource):
class Meta:
queryset = User.objects.all()
resource_name = 'auth/user'
excludes = ['email', 'password', 'is_superuser']
serializer = Serializer(formats=['json', 'plist'])
Enabling the built-in (but disabled by default) JSONP support looks like:
from django.contrib.auth.models import User
from tastypie.resources import ModelResource
from tastypie.serializers import Serializer
class UserResource(ModelResource):
class Meta:
queryset = User.objects.all()
resource_name = 'auth/user'
excludes = ['email', 'password', 'is_superuser']
serializer = Serializer(formats=['json', 'jsonp', 'xml', 'yaml', 'html', 'plist'])
Serialization Security¶
Deserialization of input from unknown or untrusted sources is an intrinsically risky endeavor and vulnerabilities are regularly found in popular format libraries. Tastypie adopts and recommends the following approach:
Support the minimum required set of formats in your application. If you do not require a format, it’s much safer to disable it completely. See TASTYPIE_DEFAULT_FORMATS setting.
Some parsers offer additional safety check for use with untrusted content. The standard Tastypie Serializer attempts to be secure by default using features like PyYAML’s safe_load function and the defusedxml security wrapper for popular Python XML libraries.
Note
Tastypie’s precautions only apply to the default Serializer. If you have written your own serializer subclass we strongly recommend that you review your code to ensure that it uses the same precautions.
If backwards compatibility forces you to load files which require risky features we strongly recommend enabling those features only for the necessary resources and making your authorization checks as strict as possible. The Authentication and Authorization checks happen before deserialization so, for example, a resource which only allowed POST or PUT requests to be made by administrators is far less exposed than a general API open to the unauthenticated internet.
Implementing Your Own Serializer¶
There are several different use cases here. We’ll cover simple examples of wanting a tweaked format & adding a different format.
To tweak a format, simply override it’s to_<format> & from_<format> methods. So adding the server time to all output might look like so:
import time
from django.utils import simplejson
from django.core.serializers import json
from tastypie.serializers import Serializer
class CustomJSONSerializer(Serializer):
def to_json(self, data, options=None):
options = options or {}
data = self.to_simple(data, options)
# Add in the current time.
data['requested_time'] = time.time()
return simplejson.dumps(data, cls=json.DjangoJSONEncoder, sort_keys=True)
def from_json(self, content):
data = simplejson.loads(content)
if 'requested_time' in data:
# Log the request here...
pass
return data
In the case of adding a different format, let’s say you want to add a CSV output option to the existing set. Your Serializer subclass might look like:
import csv
import StringIO
from tastypie.serializers import Serializer
class CSVSerializer(Serializer):
formats = ['json', 'jsonp', 'xml', 'yaml', 'html', 'plist', 'csv']
content_types = {
'json': 'application/json',
'jsonp': 'text/javascript',
'xml': 'application/xml',
'yaml': 'text/yaml',
'html': 'text/html',
'plist': 'application/x-plist',
'csv': 'text/csv',
}
def to_csv(self, data, options=None):
options = options or {}
data = self.to_simple(data, options)
raw_data = StringIO.StringIO()
# Untested, so this might not work exactly right.
for item in data:
writer = csv.DictWriter(raw_data, item.keys(), extrasaction='ignore')
writer.write(item)
return raw_data
def from_csv(self, content):
raw_data = StringIO.StringIO(content)
data = []
# Untested, so this might not work exactly right.
for item in csv.DictReader(raw_data):
data.append(item)
return data
Serializer Methods¶
A swappable class for serialization.
This handles most types of data as well as the following output formats:
* json
* jsonp
* xml
* yaml
* html
* plist
It was designed to make changing behavior easy, either by overridding the various format methods (i.e. to_json), by changing the formats/content_types options or by altering the other hook methods.
get_mime_for_format¶
- Serializer.get_mime_for_format(self, format):
Given a format, attempts to determine the correct MIME type.
If not available on the current Serializer, returns application/json by default.
format_datetime¶
- Serializer.format_datetime(data):
A hook to control how datetimes are formatted.
Can be overridden at the Serializer level (datetime_formatting) or globally (via settings.TASTYPIE_DATETIME_FORMATTING).
Default is iso-8601, which looks like “2010-12-16T03:02:14”.
format_date¶
- Serializer.format_date(data):
A hook to control how dates are formatted.
Can be overridden at the Serializer level (datetime_formatting) or globally (via settings.TASTYPIE_DATETIME_FORMATTING).
Default is iso-8601, which looks like “2010-12-16”.
format_time¶
- Serializer.format_time(data):
A hook to control how times are formatted.
Can be overridden at the Serializer level (datetime_formatting) or globally (via settings.TASTYPIE_DATETIME_FORMATTING).
Default is iso-8601, which looks like “03:02:14”.
serialize¶
- Serializer.serialize(self, bundle, format='application/json', options={}):
Given some data and a format, calls the correct method to serialize the data and returns the result.
deserialize¶
- Serializer.deserialize(self, content, format='application/json'):
Given some data and a format, calls the correct method to deserialize the data and returns the result.
to_simple¶
- Serializer.to_simple(self, data, options):
For a piece of data, attempts to recognize it and provide a simplified form of something complex.
This brings complex Python data structures down to native types of the serialization format(s).
to_etree¶
- Serializer.to_etree(self, data, options=None, name=None, depth=0):
Given some data, converts that data to an etree.Element suitable for use in the XML output.
from_etree¶
- Serializer.from_etree(self, data):
Not the smartest deserializer on the planet. At the request level, it first tries to output the deserialized subelement called “object” or “objects” and falls back to deserializing based on hinted types in the XML element attribute “type”.
to_json¶
- Serializer.to_json(self, data, options=None):
Given some Python data, produces JSON output.
from_json¶
- Serializer.from_json(self, content):
Given some JSON data, returns a Python dictionary of the decoded data.
to_jsonp¶
- Serializer.to_jsonp(self, data, options=None):
Given some Python data, produces JSON output wrapped in the provided callback.
from_xml¶
- Serializer.from_xml(self, content):
Given some XML data, returns a Python dictionary of the decoded data.
to_yaml¶
- Serializer.to_yaml(self, data, options=None):
Given some Python data, produces YAML output.
from_yaml¶
- Serializer.from_yaml(self, content):
Given some YAML data, returns a Python dictionary of the decoded data.
to_plist¶
- Serializer.to_plist(self, data, options=None):
Given some Python data, produces binary plist output.
from_plist¶
- Serializer.from_plist(self, content):
Given some binary plist data, returns a Python dictionary of the decoded data.
to_html¶
- Serializer.to_html(self, data, options=None):
Reserved for future usage.
The desire is to provide HTML output of a resource, making an API available to a browser. This is on the TODO list but not currently implemented.
from_html¶
- Serializer.from_html(self, content):
Reserved for future usage.
The desire is to handle form-based (maybe Javascript?) input, making an API available to a browser. This is on the TODO list but not currently implemented.
Throttling¶
Sometimes, the client on the other end may request data too frequently or you have a business use case that dictates that the client should be limited to a certain number of requests per hour.
For this, Tastypie includes throttling as a way to limit the number of requests in a timeframe.
Usage¶
To specify a throttle, add the Throttle class to the Meta class on the Resource:
from django.contrib.auth.models import User
from tastypie.resources import ModelResource
from tastypie.throttle import BaseThrottle
class UserResource(ModelResource):
class Meta:
queryset = User.objects.all()
resource_name = 'auth/user'
excludes = ['email', 'password', 'is_superuser']
# Add it here.
throttle = BaseThrottle(throttle_at=100)
Throttle Options¶
Each of the Throttle classes accepts the following initialization arguments:
- throttle_at - the number of requests at which the user should be throttled. Default is 150 requests.
- timeframe - the length of time (in seconds) in which the user make up to the throttle_at requests. Default is 3600 seconds ( 1 hour).
- expiration - the length of time to retain the times the user has accessed the api in the cache. Default is 604800 (1 week).
Tastypie ships with the following Throttle classes:
BaseThrottle¶
The no-op throttle option, this does no throttling but implements much of the common logic and serves as an api-compatible plug. Very useful for development.
CacheThrottle¶
This uses just the cache to manage throttling. Fast but prone to cache misses and/or cache restarts.
CacheDBThrottle¶
A write-through option that uses the cache first & foremost, but also writes through to the database to persist access times. Useful for logging client accesses & with RAM-only caches.
Implementing Your Own Throttle¶
Writing a Throttle class is not quite as simple as the other components. There are two important methods, should_be_throttled & accessed. The should_be_throttled method dictates whether or not the client should be throttled. The accessed method allows for the recording of the hit to the API.
An example of a subclass might be:
import random
from tastypie.throttle import BaseThrottle
class RandomThrottle(BaseThrottle):
def should_be_throttled(self, identifier, **kwargs):
if random.randint(0, 10) % 2 == 0:
return True
return False
def accessed(self, identifier, **kwargs):
pass
This throttle class would pick a random number between 0 & 10. If the number is even, their request is allowed through; otherwise, their request is throttled & rejected.
Paginator¶
Similar to Django’s Paginator, Tastypie includes a Paginator object which limits result sets down to sane amounts for passing to the client.
This is used in place of Django’s Paginator due to the way pagination works. limit & offset (tastypie) are used in place of page (Django) so none of the page-related calculations are necessary.
This implementation also provides additional details like the total_count of resources seen and convenience links to the previous/next pages of data as available.
Usage¶
Using this class is simple, but slightly different than the other classes used by Tastypie. Like the others, you provide the Paginator (or your own subclass) as a Meta option to the Resource in question. Unlike the others, you provide the class, NOT an instance. For example:
from django.contrib.auth.models import User
from tastypie.paginator import Paginator
from tastypie.resources import ModelResource
class UserResource(ModelResource):
class Meta:
queryset = User.objects.all()
resource_name = 'auth/user'
excludes = ['email', 'password', 'is_superuser']
# Add it here.
paginator_class = Paginator
Warning
The default paginator contains the total_count value, which shows how many objects are in the underlying object list.
Obtaining this data from the database may be inefficient, especially with large datasets, and unfiltered API requests.
See http://wiki.postgresql.org/wiki/Slow_Counting and http://www.wikivs.com/wiki/MySQL_vs_PostgreSQL#COUNT.28.2A.29 for reference, on why this may be a problem when using PostgreSQL and MySQL’s InnoDB engine.
Here’s an example solution to this problem.
Implementing Your Own Paginator¶
Adding other features to a paginator usually consists of overriding one of the built-in methods. For instance, adding a page number to the output might look like:
from tastypie.paginator import Paginator
class PageNumberPaginator(Paginator):
def page(self):
output = super(PageNumberPaginator, self).page()
output['page_number'] = int(self.offset / self.limit) + 1
return output
Another common request is to alter the structure Tastypie uses in the list view. Here’s an example of renaming:
from tastypie.paginator import Paginator
class BlogEntryPaginator(Paginator):
def page(self):
output = super(BlogEntryPaginator, self).page()
# First keep a reference.
output['pagination'] = output['meta']
output['entries'] = output['objects']
# Now nuke the original keys.
del output['meta']
del output['objects']
return output
Estimated count instead of total count¶
Here’s an example, of how you can omit total_count from the resource, and instead add an estimated_count for efficiency. See the warning above for details:
import json
from django.db import connection
from tastypie.paginator import Paginator
class EstimatedCountPaginator(Paginator):
def get_next(self, limit, offset, count):
# The parent method needs an int which is higher than "limit + offset"
# to return a url. Setting it to an unreasonably large value, so that
# the parent method will always return the url.
count = 2 ** 64
return super(NoTotalCountPaginator, self).get_next(limit, offset, count)
def get_count(self):
return None
def get_estimated_count(self):
"""Get the estimated count by using the database query planner."""
# If you do not have PostgreSQL as your DB backend, alter this method
# accordingly.
return self._get_postgres_estimated_count()
def _get_postgres_estimated_count(self):
# This method only works with postgres >= 9.0.
# If you need postgres vesrions less than 9.0, remove "(format json)"
# below and parse the text explain output.
def _get_postgres_version():
# Due to django connections being lazy, we need a cursor to make
# sure the connection.connection attribute is not None.
connection.cursor()
return connection.connection.server_version
try:
if _get_postgres_version() < 90000:
return
except AttributeError:
return
cursor = connection.cursor()
query = self.objects.all().query
# Remove limit and offset from the query, and extract sql and params.
query.low_mark = None
query.high_mark = None
query, params = self.objects.query.sql_with_params()
# Fetch the estimated rowcount from EXPLAIN json output.
query = 'explain (format json) %s' % query
cursor.execute(query, params)
explain = cursor.fetchone()[0]
# Older psycopg2 versions do not convert json automatically.
if isinstance(explain, basestring):
explain = json.loads(explain)
rows = explain[0]['Plan']['Plan Rows']
return rows
def page(self):
data = super(NoTotalCountPaginator, self).page()
data['meta']['estimated_count'] = self.get_estimated_count()
return data
GeoDjango¶
Tastypie features support for GeoDjango! Resources return and accept GeoJSON (or similarly-formatted analogs for other formats) and all spatial lookup filters are supported. Distance lookups are not yet supported.
Usage¶
Here’s an example geographic model for leaving notes in polygonal regions:
from django.contrib.gis import models
class GeoNote(models.Model):
content = models.TextField()
polys = models.MultiPolygonField(null=True, blank=True)
objects = models.GeoManager()
To define a resource that takes advantage of the geospatial features, we use tastypie.contrib.gis.resources.ModelResource:
from tastypie.contrib.gis.resources import ModelResource
class GeoNoteResource(ModelResource):
class Meta:
resource_name = 'geonotes'
queryset = GeoNote.objects.all()
filtering = {
'polys': ALL,
}
Now when we do a GET on our GeoNoteResource we get back GeoJSON in our response:
{
"content": "My note content",
"id": "1",
"polys": {
"coordinates": [[[
[-122.511067, 37.771276], [-122.510037, 37.766390999999999],
[-122.510037, 37.763812999999999], [-122.456822, 37.765847999999998],
[-122.45296, 37.766458999999998], [-122.454848, 37.773989999999998],
[-122.475362, 37.773040000000002], [-122.511067, 37.771276]
]]],
"type": "MultiPolygon"
},
"resource_uri": "/api/v1/geonotes/1/"
}
When updating or creating new resources, simply provide GeoJSON or the GeoJSON analog for your perferred format.
Filtering¶
We can filter using any standard GeoDjango spatial lookup filter. Simply provide a GeoJSON (or the analog) as a GET parameter value.
Let’s find all of our GeoNote resources that contain a point inside of Golden Gate Park:
/api/v1/geonotes/?polys__contains={"type": "Point", "coordinates": [-122.475233, 37.768617]}
Returns:
{
"meta": {
"limit": 20, "next": null, "offset": 0, "previous": null, "total_count": 1},
"objects": [
{
"content": "My note content",
"id": "1",
"polys": {
"coordinates": [[[
[-122.511067, 37.771276], [-122.510037, 37.766390999999999],
[-122.510037, 37.763812999999999], [-122.456822, 37.765847999999998],
[-122.45296, 37.766458999999998], [-122.454848, 37.773989999999998],
[-122.475362, 37.773040000000002], [-122.511067, 37.771276]
]]],
"type": "MultiPolygon"
},
"resource_uri": "/api/geonotes/1/"
}
]
}
We get back the GeoNote resource defining Golden Gate Park. Awesome!
ContentTypes and GenericForeignKeys¶
Content Types and GenericForeignKeys are for relationships where the model on one end is not defined by the model’s schema.
If you’re using GenericForeignKeys in django, you can use a GenericForeignKeyField in Tastypie.
Usage¶
Here’s an example model with a GenericForeignKey taken from the Django docs:
from django.db import models
from django.contrib.contenttypes.models import ContentType
from django.contrib.contenttypes import generic
class TaggedItem(models.Model):
tag = models.SlugField()
content_type = models.ForeignKey(ContentType)
object_id = models.PositiveIntegerField()
content_object = generic.GenericForeignKey('content_type', 'object_id')
def __unicode__(self):
return self.tag
A simple ModelResource for this model might look like this:
from tastypie.contrib.contenttypes.fields import GenericForeignKeyField
from tastypie.resources import ModelResource
from .models import Note, Quote, TaggedItem
class QuoteResource(ModelResource):
class Meta:
resource_name = 'quotes'
queryset = Quote.objects.all()
class NoteResource(ModelResource):
class Meta:
resource_name = 'notes'
queryset = Note.objects.all()
class TaggedItemResource(ModelResource):
content_object = GenericForeignKeyField({
Note: NoteResource,
Quote: QuoteResource
}, 'content_object')
class Meta:
resource_name = 'tagged_items'
queryset = TaggedItem.objects.all()
Like ToOneField, you must add your GenericForeignKey attribute to your ModelResource definition. It will not be added automatically like most other field or attribute types. When you define it, you must also define the other models and match them to their resources in a dictionary, and pass that as the first argument, the second argument is the name of the attribute on the model that holds the GenericForeignKey.
Tastypie Cookbook¶
Creating a Full OAuth 2.0 API¶
It is common to use django to provision OAuth 2.0 tokens for users and then have Tasty Pie use these tokens to authenticate users to the API. Follow this tutorial and use this custom authentication class to enable OAuth 2.0 authentication with Tasty Pie.:
# api.py
from tastypie.resources import ModelResource
from tastypie.authorization import DjangoAuthorization
from polls.models import Poll, Choice
from tastypie import fields
from authentication import OAuth20Authentication
class ChoiceResource(ModelResource):
class Meta:
queryset = Choice.objects.all()
resource_name = 'choice'
authorization = DjangoAuthorization()
authentication = OAuth20Authentication()
class PollResource(ModelResource):
choices = fields.ToManyField(ChoiceResource, 'choice_set', full=True)
class Meta:
queryset = Poll.objects.all()
resource_name = 'poll'
authorization = DjangoAuthorization()
authentication = OAuth20Authentication()
Adding Custom Values¶
You might encounter cases where you wish to include additional data in a response which is not obtained from a field or method on your model. You can easily extend the dehydrate() method to provide additional values:
class MyModelResource(Resource):
class Meta:
qs = MyModel.objects.all()
def dehydrate(self, bundle):
bundle.data['custom_field'] = "Whatever you want"
return bundle
Per-Request Alterations To The Queryset¶
A common pattern is needing to limit a queryset by something that changes per-request, for instance the date/time. You can accomplish this by lightly modifying get_object_list:
from tastypie.utils import now
class MyResource(ModelResource):
class Meta:
queryset = MyObject.objects.all()
def get_object_list(self, request):
return super(MyResource, self).get_object_list(request).filter(start_date__gte=now)
Using Your Resource In Regular Views¶
In addition to using your resource classes to power the API, you can also use them to write other parts of your application, such as your views. For instance, if you wanted to encode user information in the page for some Javascript’s use, you could do the following:
# views.py
from django.shortcuts import render_to_response
from myapp.api.resources import UserResource
def user_detail(request, username):
ur = UserResource()
user = ur.obj_get(username=username)
# Other things get prepped to go into the context then...
ur_bundle = ur.build_bundle(obj=user, request=request)
return render_to_response('myapp/user_detail.html', {
# Other things here.
"user_json": ur.serialize(None, ur.full_dehydrate(ur_bundle), 'application/json'),
})
Example of getting a list of users:
def user_list(request):
res = UserResource()
request_bundle = res.build_bundle(request=request)
queryset = res.obj_get_list(request_bundle)
bundles = []
for obj in queryset:
bundle = res.build_bundle(obj=obj, request=request)
bundles.append(res.full_dehydrate(bundle, for_list=True))
list_json = res.serialize(None, bundles, "application/json")
return render_to_response('myapp/user_list.html', {
# Other things here.
"list_json": list_json,
})
Then in template you could convert JSON into JavaScript object:
<script>
var json = "{{list_json|escapejs}}";
var users = JSON.parse(json);
</script>
Using Non-PK Data For Your URLs¶
By convention, ModelResources usually expose the detail endpoints utilizing the primary key of the Model they represent. However, this is not a strict requirement. Each URL can take other named URLconf parameters that can be used for the lookup.
For example, if you want to expose User resources by username, you can do something like the following:
# myapp/api/resources.py
class UserResource(ModelResource):
class Meta:
queryset = User.objects.all()
detail_uri_name = 'username'
def prepend_urls(self):
return [
url(r"^(?P<resource_name>%s)/(?P<username>[\w\d_.-]+)/$" % self._meta.resource_name, self.wrap_view('dispatch_detail'), name="api_dispatch_detail"),
]
The added URLconf matches before the standard URLconf included by default & matches on the username provided in the URL.
Nested Resources¶
You can also do “nested resources” (resources within another related resource) by lightly overriding the prepend_urls method & adding on a new method to handle the children:
class ParentResource(ModelResource):
children = fields.ToManyField(ChildResource, 'children')
def prepend_urls(self):
return [
url(r"^(?P<resource_name>%s)/(?P<pk>\w[\w/-]*)/children%s$" % (self._meta.resource_name, trailing_slash()), self.wrap_view('get_children'), name="api_get_children"),
]
def get_children(self, request, **kwargs):
try:
bundle = self.build_bundle(data={'pk': kwargs['pk']}, request=request)
obj = self.cached_obj_get(bundle=bundle, **self.remove_api_resource_names(kwargs))
except ObjectDoesNotExist:
return HttpGone()
except MultipleObjectsReturned:
return HttpMultipleChoices("More than one resource is found at this URI.")
child_resource = ChildResource()
return child_resource.get_detail(request, parent_id=obj.pk)
Another alternative approach is to override the dispatch method:
# myapp/api/resources.py
class EntryResource(ModelResource):
user = fields.ForeignKey(UserResource, 'user')
class Meta:
queryset = Entry.objects.all()
resource_name = 'entry'
def dispatch(self, request_type, request, **kwargs):
username = kwargs.pop('username')
kwargs['user'] = get_object_or_404(User, username=username)
return super(EntryResource, self).dispatch(request_type, request, **kwargs)
# urls.py
from django.conf.urls.defaults import *
from myapp.api import EntryResource
entry_resource = EntryResource()
urlpatterns = patterns('',
# The normal jazz here, then...
(r'^api/(?P<username>\w+)/', include(entry_resource.urls)),
)
Adding Search Functionality¶
Another common request is being able to integrate search functionality. This approach uses Haystack, though you could hook it up to any search technology. We leave the CRUD methods of the resource alone, choosing to add a new endpoint at /api/v1/notes/search/:
from django.conf.urls.defaults import *
from django.core.paginator import Paginator, InvalidPage
from django.http import Http404
from haystack.query import SearchQuerySet
from tastypie.resources import ModelResource
from tastypie.utils import trailing_slash
from notes.models import Note
class NoteResource(ModelResource):
class Meta:
queryset = Note.objects.all()
resource_name = 'notes'
def prepend_urls(self):
return [
url(r"^(?P<resource_name>%s)/search%s$" % (self._meta.resource_name, trailing_slash()), self.wrap_view('get_search'), name="api_get_search"),
]
def get_search(self, request, **kwargs):
self.method_check(request, allowed=['get'])
self.is_authenticated(request)
self.throttle_check(request)
# Do the query.
sqs = SearchQuerySet().models(Note).load_all().auto_query(request.GET.get('q', ''))
paginator = Paginator(sqs, 20)
try:
page = paginator.page(int(request.GET.get('page', 1)))
except InvalidPage:
raise Http404("Sorry, no results on that page.")
objects = []
for result in page.object_list:
bundle = self.build_bundle(obj=result.object, request=request)
bundle = self.full_dehydrate(bundle)
objects.append(bundle)
object_list = {
'objects': objects,
}
self.log_throttled_access(request)
return self.create_response(request, object_list)
Creating per-user resources¶
One might want to create an API which will require every user to authenticate and every user will be working only with objects associated with them. Let’s see how to implement it for two basic operations: listing and creation of an object.
For listing we want to list only objects for which ‘user’ field matches ‘request.user’. This could be done by applying a filter in the apply_authorization_limits method of your resource.
For creating we’d have to wrap obj_create method of ModelResource. Then the resulting code will look something like:
# myapp/api/resources.py
class EnvironmentResource(ModelResource):
class Meta:
queryset = Environment.objects.all()
resource_name = 'environment'
list_allowed_methods = ['get', 'post']
authentication = ApiKeyAuthentication()
authorization = Authorization()
def obj_create(self, bundle, **kwargs):
return super(EnvironmentResource, self).obj_create(bundle, user=bundle.request.user)
def apply_authorization_limits(self, request, object_list):
return object_list.filter(user=request.user)
camelCase JSON Serialization¶
The convention in the world of Javascript has standardized on camelCase, where Tastypie uses underscore syntax, which can lead to “ugly” looking code in Javascript. You can create a custom serializer that emits values in camelCase instead:
from tastypie.serializers import Serializer
import re
import json
class CamelCaseJSONSerializer(Serializer):
formats = ['json']
content_types = {
'json': 'application/json',
}
def to_json(self, data, options=None):
# Changes underscore_separated names to camelCase names to go from python convention to javacsript convention
data = self.to_simple(data, options)
def underscoreToCamel(match):
return match.group()[0] + match.group()[2].upper()
def camelize(data):
if isinstance(data, dict):
new_dict = {}
for key, value in data.items():
new_key = re.sub(r"[a-z]_[a-z]", underscoreToCamel, key)
new_dict[new_key] = camelize(value)
return new_dict
if isinstance(data, (list, tuple)):
for i in range(len(data)):
data[i] = camelize(data[i])
return data
return data
camelized_data = camelize(data)
return json.dumps(camelized_data, sort_keys=True)
def from_json(self, content):
# Changes camelCase names to underscore_separated names to go from javascript convention to python convention
data = json.loads(content)
def camelToUnderscore(match):
return match.group()[0] + "_" + match.group()[1].lower()
def underscorize(data):
if isinstance(data, dict):
new_dict = {}
for key, value in data.items():
new_key = re.sub(r"[a-z][A-Z]", camelToUnderscore, key)
new_dict[new_key] = underscorize(value)
return new_dict
if isinstance(data, (list, tuple)):
for i in range(len(data)):
data[i] = underscorize(data[i])
return data
return data
underscored_data = underscorize(data)
return underscored_data
Pretty-printed JSON Serialization¶
By default, Tastypie outputs JSON with no indentation or newlines (equivalent to calling json.dumps() with indent set to None). You can override this behavior in a custom serializer:
import json as simplejson
from django.core.serializers import json
from tastypie.serializers import Serializer
class PrettyJSONSerializer(Serializer):
json_indent = 2
def to_json(self, data, options=None):
options = options or {}
data = self.to_simple(data, options)
return simplejson.dumps(data, cls=json.DjangoJSONEncoder,
sort_keys=True, ensure_ascii=False, indent=self.json_indent)
Determining format via URL¶
Sometimes it’s required to allow selecting the response format by specifying it in the API URL, for example /api/v1/users.json instead of /api/v1/users/?format=json. The following snippet allows that kind of syntax additional to the default URL scheme:
# myapp/api/resources.py
# Piggy-back on internal csrf_exempt existence handling
from tastypie.resources import csrf_exempt
class UserResource(ModelResource):
class Meta:
queryset = User.objects.all()
def prepend_urls(self):
"""
Returns a URL scheme based on the default scheme to specify
the response format as a file extension, e.g. /api/v1/users.json
"""
return [
url(r"^(?P<resource_name>%s)\.(?P<format>\w+)$" % self._meta.resource_name, self.wrap_view('dispatch_list'), name="api_dispatch_list"),
url(r"^(?P<resource_name>%s)/schema\.(?P<format>\w+)$" % self._meta.resource_name, self.wrap_view('get_schema'), name="api_get_schema"),
url(r"^(?P<resource_name>%s)/set/(?P<pk_list>\w[\w/;-]*)\.(?P<format>\w+)$" % self._meta.resource_name, self.wrap_view('get_multiple'), name="api_get_multiple"),
url(r"^(?P<resource_name>%s)/(?P<pk>\w[\w/-]*)\.(?P<format>\w+)$" % self._meta.resource_name, self.wrap_view('dispatch_detail'), name="api_dispatch_detail"),
]
def determine_format(self, request):
"""
Used to determine the desired format from the request.format
attribute.
"""
if (hasattr(request, 'format') and
request.format in self._meta.serializer.formats):
return self._meta.serializer.get_mime_for_format(request.format)
return super(UserResource, self).determine_format(request)
def wrap_view(self, view):
@csrf_exempt
def wrapper(request, *args, **kwargs):
request.format = kwargs.pop('format', None)
wrapped_view = super(UserResource, self).wrap_view(view)
return wrapped_view(request, *args, **kwargs)
return wrapper
Adding to the Django Admin¶
If you’re using the django admin and ApiKeyAuthentication, you may want to see or edit ApiKeys next to users. To do this, you need to unregister the built-in UserAdmin, alter the inlines, and re-register it. This could go in any of your admin.py files. You may also want to register ApiAccess and ApiKey models on their own.:
from tastypie.admin import ApiKeyInline
from tastypie.models import ApiAccess, ApiKey
from django.contrib.auth.admin import UserAdmin
from django.contrib.auth.models import User
admin.site.register(ApiKey)
admin.site.register(ApiAccess)
class UserModelAdmin(UserAdmin):
inlines = UserAdmin.inlines + [ApiKeyInline]
admin.site.unregister(User)
admin.site.register(User,UserModelAdmin)
Using SessionAuthentication¶
If your users are logged into the site & you want Javascript to be able to access the API (assuming jQuery), the first thing to do is setup SessionAuthentication:
from django.contrib.auth.models import User
from tastypie.authentication import SessionAuthentication
from tastypie.resources import ModelResource
class UserResource(ModelResource):
class Meta:
resource_name = 'users'
queryset = User.objects.all()
authentication = SessionAuthentication()
Then you’d build a template like:
<html>
<head>
<title></title>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.7.2/jquery.min.js"></script>
<script type="text/javascript">
$(document).ready(function() {
// We use ``.ajax`` here due to the overrides.
$.ajax({
// Substitute in your API endpoint here.
url: '/api/v1/users/',
contentType: 'application/json',
// The ``X-CSRFToken`` evidently can't be set in the
// ``headers`` option, so force it here.
// This method requires jQuery 1.5+.
beforeSend: function(jqXHR, settings) {
// Pull the token out of the DOM.
jqXHR.setRequestHeader('X-CSRFToken', $('input[name=csrfmiddlewaretoken]').val());
},
success: function(data, textStatus, jqXHR) {
// Your processing of the data here.
console.log(data);
}
});
});
</script>
</head>
<body>
<!-- Include the CSRF token in the body of the HTML -->
{% csrf_token %}
</body>
</html>
There are other ways to make this function, with other libraries or other techniques for supplying the token (see https://docs.djangoproject.com/en/dev/ref/contrib/csrf/#ajax for an alternative). This is simply a starting point for getting things working.
Debugging Tastypie¶
There are some common problems people run into when using Tastypie for the first time. Some of the common problems and things to try appear below.
“I’m getting XML output in my browser but I want JSON output!”¶
This is actually not a bug and JSON support is present in your Resource. This issue is that Tastypie respects the Accept header your browser sends. Most browsers send something like:
Accept: application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,image/png,*/*;q=0.5
Note that application/xml comes first, which is a format that Tastypie handles by default, hence why you receive XML.
If you use curl from the command line, you should receive JSON by default:
curl http://localhost:8000/api/v1/
If you want JSON in the browser, simply append ?format=json to your URL. Tastypie always respects this override first, before it falls back to the Accept header.
“What’s the format for a POST or PUT?”¶
You can view full schema for your resource through Inspecting The Resource’s Schema.
In general, Tastypie will accept resources in the same format as it gives you. This means that you can see what any POST or PUT should look like by performing a GET of that resource.
Creating a duplicate of an entry, using Python and Requests:
import requests
import json
response = requests.get('http://localhost:8000/api/v1/entry/1/')
event = json.loads(response.content)
del event['id'] # We want the server to assign a new id
response = requests.post('http://localhost:8000/api/v1/entry/',
data=json.dumps(event),
headers={'content-type': 'application/json'})
The new event should be almost identical, with the exception of readonly fields. This method may fail if your model has a unique constraint, or otherwise fails validation.
This is less likely to happen on PUT, except for application logic changes (e.g. a last_update field). The following two curl commands replace and entry with an copy:
curl -H 'Accept: application/json' 'http://localhost:8000/api/v1/entry/1/' | \
curl -H 'Content-Type: application/json' -X PUT --data @- "http://localhost:8000/api/v1/entry/1/"
You can do this over an entire collection as well:
curl -H 'Accept: application/json' 'http://localhost:8000/api/v1/entry/?limit=0' | \
curl -H 'Content-Type: application/json' -X PUT --data @- "http://localhost:8000/api/v1/entry/"
“Why is my syncdb with superuser failing with a DatabaseError?”¶
More specifically, this specific DatabaseError:
django.db.utils.DatabaseError: no such table: tastypie_apikey
This is a side effect of the (disabled by default) create_api_key signal as described in the Authentication section of the documentation when used in conjunction with South.
To work around this issue, you can disable the create_api_key signal until you have completed running syncdb --migrate for the first time.
Sites Using Tastypie¶
The following sites are a partial list of people using Tastypie. I’m always interested in adding more sites, so please find me (daniellindsley) via IRC or start a mailing list thread.
LJWorld Marketplace¶
Forkinit¶
Read-only API access to recipes.
Read The Docs¶
A hosted documentation site, primarily for Python docs. General purpose read-write access.
Luzme¶
An e-book search site that lets you fetch pricing information.
Politifact¶
To power their mobile (iPhone/Android/Playbook) applications.
LocalWiki¶
LocalWiki is a tool for collaborating in local, geographic communities. It’s using Tastypie to provide an geospatially-aware REST API.
I-Am-CC.org¶
I-Am-CC.org is a tool for releasing Instagram photos under a Creative Commons license.
Dbpatterns¶
Dbpatterns is a service that allows you to create, share, explore database models on the web.
Contributing¶
Tastypie is open-source and, as such, grows (or shrinks) & improves in part due to the community. Below are some guidelines on how to help with the project.
Philosophy¶
- Tastypie is BSD-licensed. All contributed code must be either
- the original work of the author, contributed under the BSD, or...
- work taken from another project released under a BSD-compatible license.
- GPL’d (or similar) works are not eligible for inclusion.
- Tastypie’s git master branch should always be stable, production-ready & passing all tests.
- Major releases (1.x.x) are commitments to backward-compatibility of the public APIs. Any documented API should ideally not change between major releases. The exclusion to this rule is in the event of either a security issue or to accommodate changes in Django itself.
- Minor releases (x.3.x) are for the addition of substantial features or major bugfixes.
- Patch releases (x.x.4) are for minor features or bugfixes.
Guidelines For Reporting An Issue/Feature¶
So you’ve found a bug or have a great idea for a feature. Here’s the steps you should take to help get it added/fixed in Tastypie:
- First, check to see if there’s an existing issue/pull request for the bug/feature. All issues are at https://github.com/toastdriven/django-tastypie/issues and pull reqs are at https://github.com/toastdriven/django-tastypie/pulls.
- If there isn’t one there, please file an issue. The ideal report includes:
- A description of the problem/suggestion.
- How to recreate the bug.
- If relevant, including the versions of your:
- Python interpreter
- Django
- Tastypie
- Optionally of the other dependencies involved
- Ideally, creating a pull request with a (failing) test case demonstrating what’s wrong. This makes it easy for us to reproduce & fix the problem. Instructions for running the tests are at Welcome to Tastypie!
You might also hop into the IRC channel (#tastypie on irc.freenode.net) & raise your question there, as there may be someone who can help you with a work-around.
Guidelines For Contributing Code¶
If you’re ready to take the plunge & contribute back some code/docs, the process should look like:
- Fork the project on GitHub into your own account.
- Clone your copy of Tastypie.
- Make a new branch in git & commit your changes there.
- Push your new branch up to GitHub.
- Again, ensure there isn’t already an issue or pull request out there on it. If there is & you feel you have a better fix, please take note of the issue number & mention it in your pull request.
- Create a new pull request (based on your branch), including what the problem/feature is, versions of your software & referencing any related issues/pull requests.
In order to be merged into Tastypie, contributions must have the following:
- A solid patch that:
- is clear.
- works across all supported versions of Python/Django.
- follows the existing style of the code base (mostly PEP-8).
- comments included as needed.
- A test case that demonstrates the previous flaw that now passes with the included patch.
- If it adds/changes a public API, it must also include documentation for those changes.
- Must be appropriately licensed (see “Philosophy”).
- Adds yourself to the AUTHORS file.
If your contribution lacks any of these things, they will have to be added by a core contributor before being merged into Tastypie proper, which may take substantial time for the all-volunteer team to get to.
Guidelines For Core Contributors¶
If you’ve been granted the commit bit, here’s how to shepherd the changes in:
Any time you go to work on Tastypie, please use git pull --rebase to fetch the latest changes.
Any new features/bug fixes must meet the above guidelines for contributing code (solid patch/tests passing/docs included).
Commits are typically cherry-picked onto a branch off master.
- This is done so as not to include extraneous commits, as some people submit pull reqs based on their git master that has other things applied to it.
A set of commits should be squashed down to a single commit.
- git merge --squash is a good tool for performing this, as is git rebase -i HEAD~N.
- This is done to prevent anyone using the git repo from accidently pulling work-in-progress commits.
Commit messages should use past tense, describe what changed & thank anyone involved. Examples:
"""Added a new way to do per-object authorization.""" """Fixed a bug in ``Serializer.to_xml``. Thanks to joeschmoe for the report!""" """BACKWARD-INCOMPATIBLE: Altered the arguments passed to ``Bundle.__init__``. Further description appears here if the change warrants an explanation as to why it was done."""
For any patches applied from a contributor, please ensure their name appears in the AUTHORS file.
When closing issues or pull requests, please reference the SHA in the closing message (i.e. Thanks! Fixed in SHA: 6b93f6). GitHub will automatically link to it.