mirror of
https://github.com/encode/django-rest-framework.git
synced 2024-11-30 21:44:04 +03:00
332 lines
14 KiB
Markdown
332 lines
14 KiB
Markdown
---
|
|
source:
|
|
- viewsets.py
|
|
---
|
|
|
|
# ViewSets
|
|
|
|
> After routing has determined which controller to use for a request, your controller is responsible for making sense of the request and producing the appropriate output.
|
|
>
|
|
> — [Ruby on Rails Documentation][cite]
|
|
|
|
|
|
Django REST framework allows you to combine the logic for a set of related views in a single class, called a `ViewSet`. In other frameworks you may also find conceptually similar implementations named something like 'Resources' or 'Controllers'.
|
|
|
|
A `ViewSet` class is simply **a type of class-based View, that does not provide any method handlers** such as `.get()` or `.post()`, and instead provides actions such as `.list()` and `.create()`.
|
|
|
|
The method handlers for a `ViewSet` are only bound to the corresponding actions at the point of finalizing the view, using the `.as_view()` method.
|
|
|
|
Typically, rather than explicitly registering the views in a viewset in the urlconf, you'll register the viewset with a router class, that automatically determines the urlconf for you.
|
|
|
|
## Example
|
|
|
|
Let's define a simple viewset that can be used to list or retrieve all the users in the system.
|
|
|
|
from django.contrib.auth.models import User
|
|
from django.shortcuts import get_object_or_404
|
|
from myapps.serializers import UserSerializer
|
|
from rest_framework import viewsets
|
|
from rest_framework.response import Response
|
|
|
|
class UserViewSet(viewsets.ViewSet):
|
|
"""
|
|
A simple ViewSet for listing or retrieving users.
|
|
"""
|
|
def list(self, request):
|
|
queryset = User.objects.all()
|
|
serializer = UserSerializer(queryset, many=True)
|
|
return Response(serializer.data)
|
|
|
|
def retrieve(self, request, pk=None):
|
|
queryset = User.objects.all()
|
|
user = get_object_or_404(queryset, pk=pk)
|
|
serializer = UserSerializer(user)
|
|
return Response(serializer.data)
|
|
|
|
If we need to, we can bind this viewset into two separate views, like so:
|
|
|
|
user_list = UserViewSet.as_view({'get': 'list'})
|
|
user_detail = UserViewSet.as_view({'get': 'retrieve'})
|
|
|
|
Typically we wouldn't do this, but would instead register the viewset with a router, and allow the urlconf to be automatically generated.
|
|
|
|
from myapp.views import UserViewSet
|
|
from rest_framework.routers import DefaultRouter
|
|
|
|
router = DefaultRouter()
|
|
router.register(r'users', UserViewSet, basename='user')
|
|
urlpatterns = router.urls
|
|
|
|
Rather than writing your own viewsets, you'll often want to use the existing base classes that provide a default set of behavior. For example:
|
|
|
|
class UserViewSet(viewsets.ModelViewSet):
|
|
"""
|
|
A viewset for viewing and editing user instances.
|
|
"""
|
|
serializer_class = UserSerializer
|
|
queryset = User.objects.all()
|
|
|
|
There are two main advantages of using a `ViewSet` class over using a `View` class.
|
|
|
|
* Repeated logic can be combined into a single class. In the above example, we only need to specify the `queryset` once, and it'll be used across multiple views.
|
|
* By using routers, we no longer need to deal with wiring up the URL conf ourselves.
|
|
|
|
Both of these come with a trade-off. Using regular views and URL confs is more explicit and gives you more control. ViewSets are helpful if you want to get up and running quickly, or when you have a large API and you want to enforce a consistent URL configuration throughout.
|
|
|
|
|
|
## ViewSet actions
|
|
|
|
The default routers included with REST framework will provide routes for a standard set of create/retrieve/update/destroy style actions, as shown below:
|
|
|
|
class UserViewSet(viewsets.ViewSet):
|
|
"""
|
|
Example empty viewset demonstrating the standard
|
|
actions that will be handled by a router class.
|
|
|
|
If you're using format suffixes, make sure to also include
|
|
the `format=None` keyword argument for each action.
|
|
"""
|
|
|
|
def list(self, request):
|
|
pass
|
|
|
|
def create(self, request):
|
|
pass
|
|
|
|
def retrieve(self, request, pk=None):
|
|
pass
|
|
|
|
def update(self, request, pk=None):
|
|
pass
|
|
|
|
def partial_update(self, request, pk=None):
|
|
pass
|
|
|
|
def destroy(self, request, pk=None):
|
|
pass
|
|
|
|
## Introspecting ViewSet actions
|
|
|
|
During dispatch, the following attributes are available on the `ViewSet`.
|
|
|
|
* `basename` - the base to use for the URL names that are created.
|
|
* `action` - the name of the current action (e.g., `list`, `create`).
|
|
* `detail` - boolean indicating if the current action is configured for a list or detail view.
|
|
* `suffix` - the display suffix for the viewset type - mirrors the `detail` attribute.
|
|
* `name` - the display name for the viewset. This argument is mutually exclusive to `suffix`.
|
|
* `description` - the display description for the individual view of a viewset.
|
|
|
|
You may inspect these attributes to adjust behavior based on the current action. For example, you could restrict permissions to everything except the `list` action similar to this:
|
|
|
|
def get_permissions(self):
|
|
"""
|
|
Instantiates and returns the list of permissions that this view requires.
|
|
"""
|
|
if self.action == 'list':
|
|
permission_classes = [IsAuthenticated]
|
|
else:
|
|
permission_classes = [IsAdminUser]
|
|
return [permission() for permission in permission_classes]
|
|
|
|
## Marking extra actions for routing
|
|
|
|
If you have ad-hoc methods that should be routable, you can mark them as such with the `@action` decorator. Like regular actions, extra actions may be intended for either a single object, or an entire collection. To indicate this, set the `detail` argument to `True` or `False`. The router will configure its URL patterns accordingly. e.g., the `DefaultRouter` will configure detail actions to contain `pk` in their URL patterns.
|
|
|
|
A more complete example of extra actions:
|
|
|
|
from django.contrib.auth.models import User
|
|
from rest_framework import status, viewsets
|
|
from rest_framework.decorators import action
|
|
from rest_framework.response import Response
|
|
from myapp.serializers import UserSerializer, PasswordSerializer
|
|
|
|
class UserViewSet(viewsets.ModelViewSet):
|
|
"""
|
|
A viewset that provides the standard actions
|
|
"""
|
|
queryset = User.objects.all()
|
|
serializer_class = UserSerializer
|
|
|
|
@action(detail=True, methods=['post'])
|
|
def set_password(self, request, pk=None):
|
|
user = self.get_object()
|
|
serializer = PasswordSerializer(data=request.data)
|
|
if serializer.is_valid():
|
|
user.set_password(serializer.validated_data['password'])
|
|
user.save()
|
|
return Response({'status': 'password set'})
|
|
else:
|
|
return Response(serializer.errors,
|
|
status=status.HTTP_400_BAD_REQUEST)
|
|
|
|
@action(detail=False)
|
|
def recent_users(self, request):
|
|
recent_users = User.objects.all().order_by('-last_login')
|
|
|
|
page = self.paginate_queryset(recent_users)
|
|
if page is not None:
|
|
serializer = self.get_serializer(page, many=True)
|
|
return self.get_paginated_response(serializer.data)
|
|
|
|
serializer = self.get_serializer(recent_users, many=True)
|
|
return Response(serializer.data)
|
|
|
|
|
|
The `action` decorator will route `GET` requests by default, but may also accept other HTTP methods by setting the `methods` argument. For example:
|
|
|
|
@action(detail=True, methods=['post', 'delete'])
|
|
def unset_password(self, request, pk=None):
|
|
...
|
|
|
|
Argument `methods` also supports HTTP methods defined as [HTTPMethod](https://docs.python.org/3/library/http.html#http.HTTPMethod). Example below is identical to the one above:
|
|
|
|
from http import HTTPMethod
|
|
|
|
@action(detail=True, methods=[HTTPMethod.POST, HTTPMethod.DELETE])
|
|
def unset_password(self, request, pk=None):
|
|
...
|
|
|
|
The decorator allows you to override any viewset-level configuration such as `permission_classes`, `serializer_class`, `filter_backends`...:
|
|
|
|
@action(detail=True, methods=['post'], permission_classes=[IsAdminOrIsSelf])
|
|
def set_password(self, request, pk=None):
|
|
...
|
|
|
|
The two new actions will then be available at the urls `^users/{pk}/set_password/$` and `^users/{pk}/unset_password/$`. Use the `url_path` and `url_name` parameters to change the URL segment and the reverse URL name of the action.
|
|
|
|
To view all extra actions, call the `.get_extra_actions()` method.
|
|
|
|
### Routing additional HTTP methods for extra actions
|
|
|
|
Extra actions can map additional HTTP methods to separate `ViewSet` methods. For example, the above password set/unset methods could be consolidated into a single route. Note that additional mappings do not accept arguments.
|
|
|
|
```python
|
|
@action(detail=True, methods=["put"], name="Change Password")
|
|
def password(self, request, pk=None):
|
|
"""Update the user's password."""
|
|
...
|
|
|
|
|
|
@password.mapping.delete
|
|
def delete_password(self, request, pk=None):
|
|
"""Delete the user's password."""
|
|
...
|
|
```
|
|
|
|
## Reversing action URLs
|
|
|
|
If you need to get the URL of an action, use the `.reverse_action()` method. This is a convenience wrapper for `reverse()`, automatically passing the view's `request` object and prepending the `url_name` with the `.basename` attribute.
|
|
|
|
Note that the `basename` is provided by the router during `ViewSet` registration. If you are not using a router, then you must provide the `basename` argument to the `.as_view()` method.
|
|
|
|
Using the example from the previous section:
|
|
|
|
```pycon
|
|
>>> view.reverse_action("set-password", args=["1"])
|
|
'http://localhost:8000/api/users/1/set_password'
|
|
```
|
|
|
|
Alternatively, you can use the `url_name` attribute set by the `@action` decorator.
|
|
|
|
```pycon
|
|
>>> view.reverse_action(view.set_password.url_name, args=['1'])
|
|
'http://localhost:8000/api/users/1/set_password'
|
|
```
|
|
|
|
The `url_name` argument for `.reverse_action()` should match the same argument to the `@action` decorator. Additionally, this method can be used to reverse the default actions, such as `list` and `create`.
|
|
|
|
---
|
|
|
|
# API Reference
|
|
|
|
## ViewSet
|
|
|
|
The `ViewSet` class inherits from `APIView`. You can use any of the standard attributes such as `permission_classes`, `authentication_classes` in order to control the API policy on the viewset.
|
|
|
|
The `ViewSet` class does not provide any implementations of actions. In order to use a `ViewSet` class you'll override the class and define the action implementations explicitly.
|
|
|
|
## GenericViewSet
|
|
|
|
The `GenericViewSet` class inherits from `GenericAPIView`, and provides the default set of `get_object`, `get_queryset` methods and other generic view base behavior, but does not include any actions by default.
|
|
|
|
In order to use a `GenericViewSet` class you'll override the class and either mixin the required mixin classes, or define the action implementations explicitly.
|
|
|
|
## ModelViewSet
|
|
|
|
The `ModelViewSet` class inherits from `GenericAPIView` and includes implementations for various actions, by mixing in the behavior of the various mixin classes.
|
|
|
|
The actions provided by the `ModelViewSet` class are `.list()`, `.retrieve()`, `.create()`, `.update()`, `.partial_update()`, and `.destroy()`.
|
|
|
|
#### Example
|
|
|
|
Because `ModelViewSet` extends `GenericAPIView`, you'll normally need to provide at least the `queryset` and `serializer_class` attributes. For example:
|
|
|
|
class AccountViewSet(viewsets.ModelViewSet):
|
|
"""
|
|
A simple ViewSet for viewing and editing accounts.
|
|
"""
|
|
queryset = Account.objects.all()
|
|
serializer_class = AccountSerializer
|
|
permission_classes = [IsAccountAdminOrReadOnly]
|
|
|
|
Note that you can use any of the standard attributes or method overrides provided by `GenericAPIView`. For example, to use a `ViewSet` that dynamically determines the queryset it should operate on, you might do something like this:
|
|
|
|
class AccountViewSet(viewsets.ModelViewSet):
|
|
"""
|
|
A simple ViewSet for viewing and editing the accounts
|
|
associated with the user.
|
|
"""
|
|
serializer_class = AccountSerializer
|
|
permission_classes = [IsAccountAdminOrReadOnly]
|
|
|
|
def get_queryset(self):
|
|
return self.request.user.accounts.all()
|
|
|
|
Note however that upon removal of the `queryset` property from your `ViewSet`, any associated [router][routers] will be unable to derive the basename of your Model automatically, and so you will have to specify the `basename` kwarg as part of your [router registration][routers].
|
|
|
|
Also note that although this class provides the complete set of create/list/retrieve/update/destroy actions by default, you can restrict the available operations by using the standard permission classes.
|
|
|
|
## ReadOnlyModelViewSet
|
|
|
|
The `ReadOnlyModelViewSet` class also inherits from `GenericAPIView`. As with `ModelViewSet` it also includes implementations for various actions, but unlike `ModelViewSet` only provides the 'read-only' actions, `.list()` and `.retrieve()`.
|
|
|
|
#### Example
|
|
|
|
As with `ModelViewSet`, you'll normally need to provide at least the `queryset` and `serializer_class` attributes. For example:
|
|
|
|
class AccountViewSet(viewsets.ReadOnlyModelViewSet):
|
|
"""
|
|
A simple ViewSet for viewing accounts.
|
|
"""
|
|
queryset = Account.objects.all()
|
|
serializer_class = AccountSerializer
|
|
|
|
Again, as with `ModelViewSet`, you can use any of the standard attributes and method overrides available to `GenericAPIView`.
|
|
|
|
# Custom ViewSet base classes
|
|
|
|
You may need to provide custom `ViewSet` classes that do not have the full set of `ModelViewSet` actions, or that customize the behavior in some other way.
|
|
|
|
## Example
|
|
|
|
To create a base viewset class that provides `create`, `list` and `retrieve` operations, inherit from `GenericViewSet`, and mixin the required actions:
|
|
|
|
from rest_framework import mixins, viewsets
|
|
|
|
class CreateListRetrieveViewSet(mixins.CreateModelMixin,
|
|
mixins.ListModelMixin,
|
|
mixins.RetrieveModelMixin,
|
|
viewsets.GenericViewSet):
|
|
"""
|
|
A viewset that provides `retrieve`, `create`, and `list` actions.
|
|
|
|
To use it, override the class and set the `.queryset` and
|
|
`.serializer_class` attributes.
|
|
"""
|
|
pass
|
|
|
|
By creating your own base `ViewSet` classes, you can provide common behavior that can be reused in multiple viewsets across your API.
|
|
|
|
[cite]: https://guides.rubyonrails.org/action_controller_overview.html
|
|
[routers]: routers.md
|