.. _ref-resources: ========= 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 :doc:`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 "``_"). 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. 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_`` 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. If 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_`` 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 what how the data from the client is interpreted & placed on the data model. ``hydrate`` ~~~~~~~~~~~ The ``hydrate`` method allows you to make final 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): return bundle.data['title'].lower() The return value is updated in the ``bundle.obj``. 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 what 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. ``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 ``POST/PUT`` with an empty body & a ``Location`` header of where to request the full resource. If ``True``, ``HttpAccepted`` (202) is returned on ``POST/PUT`` with a body containing all the data in a serialized form. Basic Filtering =============== :class:`~tastypie.resources.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 :mod:`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 ` rather than simple database queries) your :class:`~tastypie.resources.Resource` may define a custom :meth:`~tastypie.resource.Resource.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 ``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`` ------------- .. method:: 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`` ------------- .. method:: 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`` ----------------- .. method:: Resource.override_urls(self) A hook for adding your own URLs or overriding 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`` -------- .. method:: 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`` -------------------- .. method:: 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`` ------------- .. method:: 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`` --------------- .. method:: 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`` -------------------------------- .. method:: 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`` ---------------------------------- .. method:: 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`` -------------------------------- .. method:: 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`` ---------------------------------- .. method:: 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`` ----------------- .. method:: 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`` ------------------- .. method:: 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`` ------------ .. method:: 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`` ----------------------------- .. method:: 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`` ---------------- .. method:: 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`` ----------------- .. method:: Resource.is_authorized(self, request, object=None) 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`` -------------------- .. method:: 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`` ------------------ .. method:: 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`` ------------------------ .. method:: 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`` ---------------- .. method:: 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`` ----------------- .. method:: 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`` ----------------- .. method:: 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_resource_uri`` -------------------- .. method:: Resource.get_resource_uri(self, bundle_or_obj) *This needs to be implemented at the user level.* A ``return reverse("api_dispatch_detail", kwargs={'resource_name': self.resource_name, 'pk': object.id})`` should be all that would be needed. ``ModelResource`` includes a full working version specific to Django's ``Models``. ``get_resource_list_uri`` ------------------------- .. method:: Resource.get_resource_list_uri(self) Returns a URL specific to this resource's list endpoint. ``get_via_uri`` --------------- .. method:: 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`` ------------------ .. method:: Resource.full_dehydrate(self, bundle) Given a bundle with an object instance, extract the information from it to populate the resource. ``dehydrate`` ------------- .. method:: 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`` ---------------- .. method:: Resource.full_hydrate(self, bundle) Given a populated bundle, distill it and turn it back into a full-fledged object instance. ``hydrate`` ----------- .. method:: 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. ``hydrate_m2m`` --------------- .. method:: Resource.hydrate_m2m(self, bundle) Populate the ManyToMany data on the instance. ``build_schema`` ---------------- .. method:: 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`` -------------------------- .. method:: 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`` ---------------------- .. method:: 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`` ------------------- .. method:: 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`` ------------------------------ .. method:: Resource.apply_authorization_limits(self, request, object_list) Allows the ``Authorization`` class to further limit the object list. Also a hook to customize per ``Resource``. Calls ``Authorization.apply_limits`` if available. ``can_create`` -------------- .. method:: Resource.can_create(self) Checks to ensure ``post`` is within ``allowed_methods``. ``can_update`` -------------- .. method:: Resource.can_update(self) Checks to ensure ``put`` is within ``allowed_methods``. Used when hydrating related data. ``can_delete`` -------------- .. method:: Resource.can_delete(self) Checks to ensure ``delete`` is within ``allowed_methods``. ``apply_filters`` ----------------- .. method:: 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`` ---------------- .. method:: Resource.obj_get_list(self, request=None, **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`` ----------------------- .. method:: Resource.cached_obj_get_list(self, request=None, **kwargs) A version of ``obj_get_list`` that uses the cache as a means to get commonly-accessed data faster. ``obj_get`` ----------- .. method:: Resource.obj_get(self, request=None, **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`` ------------------ .. method:: Resource.cached_obj_get(self, request=None, **kwargs) A version of ``obj_get`` that uses the cache as a means to get commonly-accessed data faster. ``obj_create`` -------------- .. method:: Resource.obj_create(self, bundle, request=None, **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``. ``obj_update`` -------------- .. method:: Resource.obj_update(self, bundle, request=None, **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`` ------------------- .. method:: Resource.obj_delete_list(self, request=None, **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`` -------------- .. method:: Resource.obj_delete(self, request=None, **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`` ------------------- .. method:: 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`` ------------ .. method:: Resource.is_valid(self, bundle, request=None) 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`` ------------ .. method:: 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`` ------------ .. method:: 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`` -------------- .. method:: 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`` ------------ .. method:: 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`` -------------- .. method:: 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`` ------------- .. method:: 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`` --------------- .. method:: 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`` --------------- .. method:: 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`` ----------------- .. method:: 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`` -------------- .. method:: 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. ``patch_detail`` ---------------- .. method:: 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). ``get_schema`` -------------- .. method:: Resource.get_schema(self, request, **kwargs) Returns a serialized form of the schema of the resource. Calls ``build_schema`` to generate the data. This method only responds to HTTP GET. Should return a HttpResponse (200 OK). ``get_multiple`` ---------------- .. method:: Resource.get_multiple(self, request, **kwargs) Returns a serialized list of resources based on the identifiers from the URL. Calls ``obj_get`` to fetch only the objects requested. This method only responds to HTTP GET. Should return a HttpResponse (200 OK). ``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`` --------------------- .. method:: 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`` ------------------------------- .. method:: 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`` -------------- .. method:: 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`` ------------------- .. method:: 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`` ----------------- .. method:: 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`` ----------------- .. method:: 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`` ----------------- .. method:: 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`` ------------------- .. method:: 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`` ---------------- .. method:: 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`` ----------- .. method:: 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`` -------------- .. method:: ModelResource.obj_create(self, bundle, **kwargs) A ORM-specific implementation of ``obj_create``. ``obj_update`` -------------- .. method:: ModelResource.obj_update(self, bundle, **kwargs) A ORM-specific implementation of ``obj_update``. ``obj_delete_list`` ------------------- .. method:: 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`` -------------- .. method:: 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`` ------------ .. method:: ModelResource.rollback(self, bundles) A ORM-specific implementation of ``rollback``. Given the list of bundles, delete all models pertaining to those bundles. ``save_related`` ---------------- .. method:: ModelResource.save_related(self, bundle) Handles the saving of related non-M2M data. Calling assigning ``child.parent = parent`` & then calling ``Child.save`` isn't good enough to make sure the ``parent`` is saved. To get around this, we go through all our related fields & call ``save`` on them if they have related, non-M2M data. M2M data is handled by the ``ModelResource.save_m2m`` method. ``save_m2m`` ------------ .. method:: 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. ``get_resource_uri`` -------------------- .. method:: ModelResource.get_resource_uri(self, bundle_or_obj) Handles generating a resource URI for a single resource. Uses the model's ``pk`` in order to create the URI.