Django-Rest-Framework 教程: 3. 使用 class based views

作者: Desmond
Chen, 发布日期: 2014-05-31, 修改日期: 2014-05-31

在上一篇Django-Rest-Framework
教程: 2. Requests 和 Responses中, 使用的是function based views. 在本篇中, 主要介绍怎样使用class based views.

1. 修改views.py

首先修改snippet_list view:

# snippets/views.py
from snippets.models import Snippet
from snippets.serializers import SnippetSerializer
from django.http import Http404
from rest_framework.views import APIView
from rest_framework.response import Response
from rest_framework import status

class SnippetList(APIView):
"""
展示所有存在的snippet, 或建立新的snippet
"""
def get(self, request, format=None):
snippets = Snippet.objects.all()
serializer = SnippetSerializer(snippets, many=True)
return Response(serializer.data)

def post(self, request, format=None):
serializer = SnippetSerializer(data=request.DATA)
if serializer.is_valid():
serializer.save()
return Response(serializer.data, status=status.HTTP_201_CREATED)
return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)

使用class based view代替 snippet_list后, 两者的代码非常相似, 但对于不同Http动作, 分离效果更为优秀. 对于snippet_detail:

# snippets/views.py
class SnippetDetail(APIView):
"""
展示, 更新或删除一个snippet
"""
def get_object(self, pk):
try:
return Snippet.objects.get(pk=pk)
except Snippet.DoesNotExist:
raise Http404

def get(self, request, pk, format=None):
snippet = self.get_object(pk)
serializer = SnippetSerializer(snippet)
return Response(serializer.data)

def put(self, request, pk, format=None):
snippet = self.get_object(pk)
serializer = SnippetSerializer(snippet, data=request.DATA)
if serializer.is_valid():
serializer.save()
return Response(serializer.data)
return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)

def delete(self, request, pk, format=None):
snippet = self.get_object(pk)
snippet.delete()
return Response(status=status.HTTP_204_NO_CONTENT)

更新urls.py:

# snippets/urls.py
from django.conf.urls import patterns, url
from rest_framework.urlpatterns import format_suffix_patterns
from snippets import views

urlpatterns = patterns('',
url(r'^snippets/$', views.SnippetList.as_view()),
url(r'^snippets/(?P<pk>[0-9]+)/$', views.SnippetDetail.as_view()),
)

urlpatterns = format_suffix_patterns(urlpatterns)

class based view改造完成, 现在可以使用之前的测试方法进行测试了.

2. 使用 Mixins

使用class based views的一大好处是, 我们可以使用各种mixin.

Django-rest-framework为我们提供了许多现成的mixins, 方便我们像使用model-backed API一样构建 "创建/获取/更新/删除" API. 我们试着使用Mixins改写原先的view.

GenericAPIView为我们提供了view核心的功能, 而ListModelMixin和CreateModelMixin为我们提供了.list()和.create()功能. 我们将这些功能与http动作绑定:

# snippets/views.py
from snippets.models import Snippet
from snippets.serializers import SnippetSerializer
from rest_framework import mixins
from rest_framework import generics

class SnippetList(mixins.ListModelMixin,
mixins.CreateModelMixin,
generics.GenericAPIView):
queryset = Snippet.objects.all()
serializer_class = SnippetSerializer

def get(self, request, *args, **kwargs):
return self.list(request, *args, **kwargs)

def post(self, request, *args, **kwargs):
return self.create(request, *args, **kwargs)

同样的, 我们使用GenericAPIView, RetrieveModelMixin, UpdateModelMixin和DestroyModelMixin改写views.py:

# snippets/views.py
class SnippetDetail(mixins.RetrieveModelMixin,
mixins.UpdateModelMixin,
mixins.DestroyModelMixin,
generics.GenericAPIView):
queryset = Snippet.objects.all()
serializer_class = SnippetSerializer

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)

3. 使用generic class based views

同Django一样, django-rest-framework为我们提供了现成的generic class based views. 接下来我们使用这些GCBVs再一次修改原有的views.py:

# snippets/views.py
from snippets.models import Snippet
from snippets.serializers import SnippetSerializer
from rest_framework import generics

class SnippetList(generics.ListCreateAPIView):
queryset = Snippet.objects.all()
serializer_class = SnippetSerializer

class SnippetDetail(generics.RetrieveUpdateDestroyAPIView):
queryset = Snippet.objects.all()
serializer_class = SnippetSerializer

可以发现, 使用GCBVs后, 代码变得的更为精简易懂.