.. _ref-cookbook: ================= 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. .. testsetup:: import os import django from django.core.management import call_command os.environ['DJANGO_SETTINGS_MODULE'] = 'myproject.settings' django.setup() call_command('migrate', verbosity=0) .. testcode:: # api.py from tastypie import fields from tastypie.authorization import DjangoAuthorization from tastypie.resources import ModelResource, Resource from myapp.models import Poll, Choice 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() .. testoutput:: :options: +NORMALIZE_WHITESPACE :hide: ... 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 :meth:`~tastypie.resources.Resource.dehydrate` method to provide additional values: .. testcode:: from myapp.models import MyModel class MyModelResource(Resource): class Meta: queryset = MyModel.objects.all() def dehydrate(self, bundle): bundle.data['custom_field'] = "Whatever you want" return bundle .. testoutput:: :options: +NORMALIZE_WHITESPACE :hide: ... 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``: .. testcode:: from django.utils import timezone from myapp.models import MyModel class MyModelResource(ModelResource): class Meta: queryset = MyModel.objects.all() def get_object_list(self, request): return super(MyModelResource, self).get_object_list(request).filter(start_date__gte=timezone.now()) .. testoutput:: :options: +NORMALIZE_WHITESPACE :hide: ... 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. In this case, ``user_json`` will not include a valid ``resource_uri``: .. testcode:: # views.py from django.shortcuts import render_to_response from myapp.api.resources import UserResource def user_detail(request, username): res = UserResource() request_bundle = res.build_bundle(request=request) user = res.obj_get(request_bundle, username=username) # Other things get prepped to go into the context then... user_bundle = res.build_bundle(request=request, obj=user) user_json = res.serialize(None, res.full_dehydrate(user_bundle), "application/json") return render_to_response("myapp/user_detail.html", { # Other things here. "user_json": user_json, }) .. testoutput:: :options: +NORMALIZE_WHITESPACE :hide: ... To include a valid ``resource_uri``, the resource must be associated with an ``tastypie.Api`` instance, as below: .. testcode:: # urls.py from tastypie.api import Api from myapp.api.resources import UserResource my_api = Api(api_name='v1') my_api.register(UserResource()) # views.py from myapp.urls import my_api def user_detail(request, username): res = my_api.canonical_resource_for('user') # continue as above... .. testoutput:: :options: +NORMALIZE_WHITESPACE :hide: ... Alternatively, to get a valid ``resource_uri`` you may pass in the ``api_name`` parameter directly to the Resource: .. testcode:: # views.py from django.shortcuts import render_to_response from myapp.api.resources import UserResource def user_detail(request, username): res = UserResource(api_name='v1') # continue as above... .. testoutput:: :options: +NORMALIZE_WHITESPACE :hide: ... Example of getting a list of users: .. testcode:: 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, }) .. testoutput:: :options: +NORMALIZE_WHITESPACE :hide: ... Then in template you could convert JSON into JavaScript object:: Using Non-PK Data For Your URLs ------------------------------- By convention, ``ModelResource``\s 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: .. testcode:: # myapp/api/resources.py from django.contrib.auth.models import User class UserResource(ModelResource): class Meta: queryset = User.objects.all() detail_uri_name = 'username' def prepend_urls(self): return [ url(r"^(?P%s)/(?P[\w\d_.-]+)/$" % self._meta.resource_name, self.wrap_view('dispatch_detail'), name="api_dispatch_detail"), ] .. testoutput:: :options: +NORMALIZE_WHITESPACE :hide: ... The added URLconf matches before the standard URLconf included by default & matches on the username provided in the URL. Another alternative approach is to override the ``dispatch`` method: .. testcode:: # myapp/api/resources.py from myapp.models import MyModel class MyModelResource(ModelResource): user = fields.ForeignKey(UserResource, 'user') class Meta: queryset = MyModel.objects.all() resource_name = 'mymodel' def dispatch(self, request_type, request, **kwargs): username = kwargs.pop('username') kwargs['user'] = get_object_or_404(User, username=username) return super(MyModelResource, self).dispatch(request_type, request, **kwargs) # urls.py from django.conf.urls import url, include mymodel_resource = MyModelResource() urlpatterns = [ # The normal jazz here, then... url(r'^api/(?P\w+)/', include(mymodel_resource.urls)), ] .. testoutput:: :options: +NORMALIZE_WHITESPACE :hide: ... Nested Resources ---------------- You can also do "nested resources" (resources within another related resource) by lightly overriding the ``prepend_urls`` method & adding on a new method to handle the children: .. testcode:: class ChildResource(ModelResource): pass class ParentResource(ModelResource): children = fields.ToManyField(ChildResource, 'children') def prepend_urls(self): return [ url(r"^(?P%s)/(?P\w[\w/-]*)/children%s$" % (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_list(request, parent_id=obj.pk) .. testoutput:: :options: +NORMALIZE_WHITESPACE :hide: ... 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 import url, include 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%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) .. _Haystack: http://haystacksearch.org/ 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: .. testcode:: # myapp/api/resources.py from tastypie.authentication import ApiKeyAuthentication from tastypie.authorization import Authorization class MyModelResource(ModelResource): class Meta: queryset = MyModel.objects.all() resource_name = 'mymodel' list_allowed_methods = ['get', 'post'] authentication = ApiKeyAuthentication() authorization = Authorization() def obj_create(self, bundle, **kwargs): return super(MyModelResource, self).obj_create(bundle, user=bundle.request.user) def apply_authorization_limits(self, request, object_list): return object_list.filter(user=request.user) .. testoutput:: :options: +NORMALIZE_WHITESPACE :hide: ... 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: .. testcode:: import re import json from tastypie.serializers import Serializer 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 .. testoutput:: :options: +NORMALIZE_WHITESPACE :hide: ... Pretty-printed JSON Serialization --------------------------------- By default, Tastypie outputs JSON with no indentation or newlines (equivalent to calling :py:func:`json.dumps` with *indent* set to ``None``). You can override this behavior in a custom serializer: .. testcode:: import json from django.core.serializers.json import DjangoJSONEncoder 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 json.dumps(data, cls=DjangoJSONEncoder, sort_keys=True, ensure_ascii=False, indent=self.json_indent) .. testoutput:: :options: +NORMALIZE_WHITESPACE :hide: ... 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: .. testcode:: # myapp/api/resources.py from django.contrib.auth.models import User # 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%s)\.(?P\w+)$" % self._meta.resource_name, self.wrap_view('dispatch_list'), name="api_dispatch_list"), url(r"^(?P%s)/schema\.(?P\w+)$" % self._meta.resource_name, self.wrap_view('get_schema'), name="api_get_schema"), url(r"^(?P%s)/set/(?P\w[\w/;-]*)\.(?P\w+)$" % self._meta.resource_name, self.wrap_view('get_multiple'), name="api_get_multiple"), url(r"^(?P%s)/(?P\w[\w/-]*)\.(?P\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 .. testoutput:: :options: +NORMALIZE_WHITESPACE :hide: ... 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.: .. testcode:: from django.contrib import admin from django.contrib.auth.admin import UserAdmin from django.contrib.auth.models import User from tastypie.admin import ApiKeyInline class UserModelAdmin(UserAdmin): inlines = UserAdmin.inlines + [ApiKeyInline] admin.site.unregister(User) admin.site.register(User, UserModelAdmin) .. testoutput:: :options: +NORMALIZE_WHITESPACE :hide: ... 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``: .. testcode:: 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() .. testoutput:: :options: +NORMALIZE_WHITESPACE :hide: ... Then you'd build a template like:: {% csrf_token %} 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.