mirror of
https://github.com/encode/django-rest-framework.git
synced 2024-11-13 13:16:55 +03:00
154 lines
6.4 KiB
Markdown
154 lines
6.4 KiB
Markdown
# Tutorial 3: Class Based Views
|
|
|
|
We can also write our API views using class based views, rather than function based views. As we'll see this is a powerful pattern that allows us to reuse common functionality, and helps us keep our code [DRY][dry].
|
|
|
|
## Rewriting our API using class based views
|
|
|
|
We'll start by rewriting the root view as a class based view. All this involves is a little bit of refactoring.
|
|
|
|
from blog.models import Comment
|
|
from blog.serializers import CommentSerializer
|
|
from django.http import Http404
|
|
from rest_framework.views import APIView
|
|
from rest_framework.response import Response
|
|
from rest_framework import status
|
|
|
|
|
|
class CommentRoot(APIView):
|
|
"""
|
|
List all comments, or create a new comment.
|
|
"""
|
|
def get(self, request, format=None):
|
|
comments = Comment.objects.all()
|
|
serializer = CommentSerializer(instance=comments)
|
|
return Response(serializer.data)
|
|
|
|
def post(self, request, format=None):
|
|
serializer = CommentSerializer(request.DATA)
|
|
if serializer.is_valid():
|
|
comment = serializer.object
|
|
comment.save()
|
|
return Response(serializer.data, status=status.HTTP_201_CREATED)
|
|
return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)
|
|
|
|
So far, so good. It looks pretty similar to the previous case, but we've got better separation between the different HTTP methods. We'll also need to update the instance view.
|
|
|
|
class CommentInstance(APIView):
|
|
"""
|
|
Retrieve, update or delete a comment instance.
|
|
"""
|
|
|
|
def get_object(self, pk):
|
|
try:
|
|
return Comment.objects.get(pk=pk)
|
|
except Comment.DoesNotExist:
|
|
raise Http404
|
|
|
|
def get(self, request, pk, format=None):
|
|
comment = self.get_object(pk)
|
|
serializer = CommentSerializer(instance=comment)
|
|
return Response(serializer.data)
|
|
|
|
def put(self, request, pk, format=None):
|
|
comment = self.get_object(pk)
|
|
serializer = CommentSerializer(request.DATA, instance=comment)
|
|
if serializer.is_valid():
|
|
comment = serializer.object
|
|
comment.save()
|
|
return Response(serializer.data)
|
|
return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)
|
|
|
|
def delete(self, request, pk, format=None):
|
|
comment = self.get_object(pk)
|
|
comment.delete()
|
|
return Response(status=status.HTTP_204_NO_CONTENT)
|
|
|
|
That's looking good. Again, it's still pretty similar to the function based view right now.
|
|
|
|
We'll also need to refactor our URLconf slightly now we're using class based views.
|
|
|
|
from django.conf.urls import patterns, url
|
|
from rest_framework.urlpatterns import format_suffix_patterns
|
|
from blogpost import views
|
|
|
|
urlpatterns = patterns('',
|
|
url(r'^$', views.CommentRoot.as_view()),
|
|
url(r'^(?P<pk>[0-9]+)$', views.CommentInstance.as_view())
|
|
)
|
|
|
|
urlpatterns = format_suffix_patterns(urlpatterns)
|
|
|
|
Okay, we're done. If you run the development server everything should be working just as before.
|
|
|
|
## Using mixins
|
|
|
|
One of the big wins of using class based views is that it allows us to easily compose reusable bits of behaviour.
|
|
|
|
The create/retrieve/update/delete operations that we've been using so far are going to be pretty simliar for any model-backed API views we create. Those bits of common behaviour are implemented in REST framework's mixin classes.
|
|
|
|
Let's take a look at how we can compose our views by using the mixin classes.
|
|
|
|
from blog.models import Comment
|
|
from blog.serializers import CommentSerializer
|
|
from rest_framework import mixins
|
|
from rest_framework import generics
|
|
|
|
class CommentRoot(mixins.ListModelMixin,
|
|
mixins.CreateModelMixin,
|
|
generics.MultipleObjectBaseView):
|
|
model = Comment
|
|
serializer_class = CommentSerializer
|
|
|
|
def get(self, request, *args, **kwargs):
|
|
return self.list(request, *args, **kwargs)
|
|
|
|
def post(self, request, *args, **kwargs):
|
|
return self.create(request, *args, **kwargs)
|
|
|
|
We'll take a moment to examine exactly what's happening here - We're building our view using `MultipleObjectBaseView`, and adding in `ListModelMixin` and `CreateModelMixin`.
|
|
|
|
The base class provides the core functionality, and the mixin classes provide the `.list()` and `.create()` actions. We're then explictly binding the `get` and `post` methods to the appropriate actions. Simple enough stuff so far.
|
|
|
|
class CommentInstance(mixins.RetrieveModelMixin,
|
|
mixins.UpdateModelMixin,
|
|
mixins.DestroyModelMixin,
|
|
generics.SingleObjectBaseView):
|
|
model = Comment
|
|
serializer_class = CommentSerializer
|
|
|
|
def get(self, request, *args, **kwargs):
|
|
return self.retrieve(request, *args, **kwargs)
|
|
|
|
def put(self, request, *args, **kwargs):
|
|
return self.update(request, *args, **kwargs)
|
|
|
|
def delete(self, request, *args, **kwargs):
|
|
return self.destroy(request, *args, **kwargs)
|
|
|
|
Pretty similar. This time we're using the `SingleObjectBaseView` class to provide the core functionality, and adding in mixins to provide the `.retrieve()`, `.update()` and `.destroy()` actions.
|
|
|
|
## Using generic class based views
|
|
|
|
Using the mixin classes we've rewritten the views to use slightly less code than before, but we can go one step further. REST framework provides a set of already mixed-in generic views that we can use.
|
|
|
|
from blog.models import Comment
|
|
from blog.serializers import CommentSerializer
|
|
from rest_framework import generics
|
|
|
|
|
|
class CommentRoot(generics.ListCreateAPIView):
|
|
model = Comment
|
|
serializer_class = CommentSerializer
|
|
|
|
|
|
class CommentInstance(generics.RetrieveUpdateDestroyAPIView):
|
|
model = Comment
|
|
serializer_class = CommentSerializer
|
|
|
|
Wow, that's pretty concise. We've got a huge amount for free, and our code looks like good, clean, idiomatic Django.
|
|
|
|
Next we'll move onto [part 4 of the tutorial][tut-4], where we'll take a look at how we can customize the behavior of our views to support a range of authentication, permissions, throttling and other aspects.
|
|
|
|
[dry]: http://en.wikipedia.org/wiki/Don't_repeat_yourself
|
|
[tut-4]: 4-authentication-permissions-and-throttling.md
|