djangorestframework

DRF Views

The essential component of DRF views is the APIView class, which subclasses Django's View class.

APIView class is a base for all the views that you might choose to use in your DRF application.

Whether it be-

function-based views
class-based views
mixins
generic view classes
viewsets

they all use the APIView class.

Class-based Views

Class-based views extend the APIView class. With them, you determine how requests will be handled and which policy attributes you're going to use.

from rest_framework.response import Response
from rest_framework.views import APIView

class DeleteAllItems(APIView):
    def delete(self, request):
        Item.objects.all().delete()
        return Response(status=status.HTTP_204_NO_CONTENT)

Policy Attributes

If you want to override the default settings for your class-based views, you can use policy attributes.

In the following example, we changed the permissions and how a response is rendered with the permission_classes and renderer_classes policy attributes:

from rest_framework.permissions import IsAuthenticated
from rest_framework.renderers import JSONRenderer
from rest_framework.response import Response
from rest_framework.views import APIView

class ItemsNotDone(APIView):

    permission_classes = [IsAuthenticated]  # policy attribute
    renderer_classes = [JSONRenderer]       # policy attribute

    def get(self, request):

        user_count = Item.objects.filter(done=False).count()
        content = {'not_done': user_count}

        return Response(content)

Function-based Views

There are two ways to directly implement APIView: With a function or with a class. If you're writing a view in the form of a function, you'll need to use the @api_view decorator.

@api_view is a decorator that converts a function-based view into an APIView subclass (thus providing the Response and Request classes). It takes a list of allowed methods for the view as an argument.

from rest_framework.decorators import api_view
from rest_framework.response import Response

@api_view(['DELETE'])
def delete_all_items(request):
    Item.objects.all().delete()
    return Response(status=status.HTTP_200_OK)

Policy Decorators

If you want to override the default settings for your function-based view, you can use policy decorators. You can use one or multiple of the following

@renderer_classes
@parser_classes
@authentication_classes
@throttle_classes
@permission_classes

Those decorators correspond to APIView subclasses. Because the @api_view decorator checks if any of the following decorators are used, they need to be added below the api_view decorator.

from rest_framework.decorators import api_view, permission_classes, renderer_classes
from rest_framework.permissions import IsAuthenticated
from rest_framework.renderers import JSONRenderer
from rest_framework.response import Response

@api_view(['GET'])
@permission_classes([IsAuthenticated])  # policy decorator
@renderer_classes([JSONRenderer])       # policy decorator
def items_not_done(request):
    user_count = Item.objects.filter(done=False).count()
    content = {'not_done': user_count}

    return Response(content)

ViewSets

A ViewSet class is simply a type of class-based View.

There are four types of ViewSets, from the most basic to the most powerful:

ViewSet
GenericViewSet
ReadOnlyModelViewSet
ModelViewSet