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.
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'], }
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.
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.
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 towrap_view
,Resource.dispatch_list
is called next. This is a thin wrapper aroundResource.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
).- the requested HTTP method is in
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 ofModelResource
, this builds the ORM filters to apply (ModelResource.build_filters
). It then gets theQuerySet
viaModelResource.get_object_list
(which performsResource.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
.
- A fetch of the available objects via
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.
- Determines the desired response format (
We bubble back up the call stack to
dispatch
. The last thingdispatch
does is potentially store that a request occurred for future throttling (Resource.log_throttled_access
) then either returns theHttpResponse
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.
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.
Think of it as package of user data & an object instance (either of which are optionally present).
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.
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.
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 owndehydrate
method on thebundle
. - While processing each field, look for a
dehydrate_<fieldname>
method on theResource
. If it's present, call it with thebundle
. - Finally, after all fields are processed, if the
dehydrate
method is present on theResource
, it is called & given the entirebundle
.
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.
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.
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.
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.
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. - Run through all fields on the
Resource
, letting each field perform its ownhydrate
method on thebundle
. - While processing each field, look for a
hydrate_<fieldname>
method on theResource
. If it's present, call it with thebundle
. - Finally, after all fields are processed, if the
hydrate
method is present on theResource
, it is called & given the entirebundle
.
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.
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.
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
.
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.
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()
The inner Meta
class allows for class-level configuration of how the
Resource
should behave. The following options are available:
Controls which serializer class theResource
should use. Default istastypie.serializers.Serializer()
.
Controls which authentication class theResource
should use. Default istastypie.authentication.Authentication()
.
Controls which authorization class theResource
should use. Default istastypie.authorization.ReadOnlyAuthorization()
.
Controls which validation class theResource
should use. Default istastypie.validation.Validation()
.
Controls which paginator class theResource
should use. Default istastypie.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.
Controls which cache class theResource
should use. Default istastypie.cache.NoCache()
.
Controls which throttle class theResource
should use. Default istastypie.throttle.BaseThrottle()
.
Controls what list & detail REST methods the
Resource
should respond to. Default isNone
, which means delegate to the more specificlist_allowed_methods
&detail_allowed_methods
options.You may specify a list like
['get', 'post', 'put', 'delete']
as a shortcut to prevent having to specify the other options.
Controls what list REST methods theResource
should respond to. Default is['get', 'post', 'put', 'delete']
.
Controls what detail REST methods theResource
should respond to. Default is['get', 'post', 'put', 'delete']
.
Controls what how many results theResource
will show at a time. Default is either theAPI_LIMIT_PER_PAGE
setting (if provided) or20
if not specified.
An override for theResource
to use when generating resource URLs. Default isNone
.
An override for the
Resource
to use when generating resource URLs. Default isNone
.If not provided, the
Resource
orModelResource
will attempt to name itself. This means a lowercase version of the classname preceding the wordResource
if present (i.e.SampleContentResource
would becomesamplecontent
).
Specifies the default serialization format theResource
should use if one is not requested (usually by theAccept
header orformat
GET parameter). Default isapplication/json
.
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.
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 theorder_by
GET parameter, you can specify either thefieldname
(ascending order) or-fieldname
(descending order).
Provides the
Resource
with the object that serves as the data source. Default isNone
.In the case of
ModelResource
, this is automatically populated by thequeryset
option and is the model class.
Provides the
Resource
with the set of Django models to respond with. Default isNone
.Unused by
Resource
but present for consistency.
Controls what introspected fields theResource
should include. A whitelist of fields. Default is[]
.
Controls what introspected fields theResource
should NOT include. A blacklist of fields. Default is[]
.
Specifies if theResource
should include an extra field that displays the detail URL (within the api) for that resource. Default isTrue
.
Specifies if theResource
should include an extra field that displays theget_absolute_url
for that object (on the site proper). Default isFalse
.
Specifies all HTTP methods (except
DELETE
) should return a serialized form of the data. Default isFalse
.If
False
,HttpNoContent
(204) is returned onPOST/PUT
with an empty body & aLocation
header of where to request the full resource.If
True
,HttpAccepted
(202) is returned onPOST/PUT
with a body containing all the data in a serialized form.
: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
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 :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
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.
.. 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.
.. 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
).
.. 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
).
.. 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.
.. 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.
.. 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
.
.. 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
.
.. 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.
.. 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.
.. 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.
.. 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.
.. 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.
.. 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.
.. method:: Resource.dispatch(self, request_type, request, **kwargs)
Handles the common operations (allowed HTTP method, authentication, throttling, method lookup) surrounding most CRUD interactions.
.. 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:: 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'])
.. 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.
.. 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
.
.. 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
.
.. 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
.
.. 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.
.. 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
.
.. 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
.
.. 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
.
.. method:: Resource.get_resource_list_uri(self)
Returns a URL specific to this resource's list endpoint.
.. method:: Resource.get_via_uri(self, uri)
This pulls apart the salient bits of the URI and populates the
resource via a obj_get
.
If you need custom behavior based on other portions of the URI, simply override this method.
.. method:: Resource.full_dehydrate(self, bundle)
Given a bundle with an object instance, extract the information from it to populate the resource.
.. 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.
.. method:: Resource.full_hydrate(self, bundle)
Given a populated bundle, distill it and turn it back into a full-fledged object instance.
.. 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.
.. method:: Resource.hydrate_m2m(self, bundle)
Populate the ManyToMany data on the instance.
.. 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.
.. 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.
.. 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.
.. 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
.
.. 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.
.. method:: Resource.can_create(self)
Checks to ensure post
is within allowed_methods
.
.. method:: Resource.can_update(self)
Checks to ensure put
is within allowed_methods
.
Used when hydrating related data.
.. method:: Resource.can_delete(self)
Checks to ensure delete
is within allowed_methods
.
.. 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
.
.. 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
.
.. 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.
.. 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
.
.. 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.
.. 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
.
.. 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
.
.. 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
.
.. 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
.
.. 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.
.. 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.
.. 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
.
.. 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).
.. 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).
.. 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
.
.. 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).
.. 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.
.. 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).
.. 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).
.. 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).
.. 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).
.. 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).
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.
.. method:: ModelResource.should_skip_field(cls, field)
Class method
Given a Django model field, return if it should be included in the contributed ApiFields.
.. 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.
.. 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.
.. 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.
.. 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.
.. 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.
.. 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.
.. 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.
.. 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.
.. 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.
.. method:: ModelResource.obj_create(self, bundle, **kwargs)
A ORM-specific implementation of obj_create
.
.. method:: ModelResource.obj_update(self, bundle, **kwargs)
A ORM-specific implementation of obj_update
.
.. 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.
.. 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.
.. method:: ModelResource.rollback(self, bundles)
A ORM-specific implementation of rollback
.
Given the list of bundles, delete all models pertaining to those bundles.
.. 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.
.. 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.
.. 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.