django rest_framework入门四-类视图APIView

上节，我们使用函数视图，用了@api_view装饰器来修饰，这一节，我们介绍类视图APIView，显然，类视图更符合面向对象的原则。

1.使用类视图APIView重写API
类视图APIView，取代@api_view装饰器，代码如下：

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

from snippets.models import Snippet
from snippets.serializers import SnippetSerializer


class SnippetList(APIView):
    def get(self, request):
        snippets = Snippet.objects.all()
        serializer = SnippetSerializer(snippets, many=True)
        return Response(serializer.data)

    def post(self, request):
        data = request.data
        serializer = SnippetSerializer(data=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)


class SnippetDetail(APIView):
    def get_object(self, pk):
        try:
            return Snippet.objects.get(pk=pk)
        except Exception as e:
            pass

    def get(self, request, pk):
        snippet = self.get_object(pk)
        serializer = SnippetSerializer(snippet)
        return Response(serializer.data)

    def put(self, request, pk):
        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):
        snippet = self.get_object(pk)
        snippet.delete()
        return Response(status=status.HTTP_204_NO_CONTENT)

2.编辑urls.py

from django.conf.urls import url, include
from django.contrib import admin

from snippets import views

urlpatterns = [
    url(r'^snippets/$', views.SnippetList.as_view()),
    url(r'^snippets/(?P<pk>[0-9]+)/$', views.SnippetDetail.as_view()),
    url(r'^admin/', admin.site.urls),
    url(r'^api-auth/', include('rest_framework.urls', namespace='rest_framework'))
]

APIView视图类，调用as_view()方法

3.使用Mixins
Mixins封装了增删改查的操作，因此可以使用Mixins简化代码，如下：

from rest_framework import status
from rest_framework.response import Response
from rest_framework.views import APIView
from rest_framework import mixins, generics

from snippets.models import Snippet
from snippets.serializers import SnippetSerializer


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)


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)

SnippetList继承了mixins的ListModelMixin和CreateModelMixin类，
赋值queryset,serializer_class属性，
然后定义了get,post方法，分别调用mixins的list，create函数。
SnippetDetail定义类似。

4.使用通用类视图generics
rest_framework定义了可能的增删改查组合，优化了多重继承的繁杂

from rest_framework import generics

from snippets.models import Snippet
from snippets.serializers import SnippetSerializer


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


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

使用generics的ListCreateAPIView和RetrieveUpdateDestroyAPIView替代mixins类
同时，去掉了get,post方法

5.使用viewsets进一步简化
viewsets包含了对一个model的增删改查全部操作，代码如下：

from rest_framework import viewsets

from snippets.models import Snippet
from snippets.serializers import SnippetSerializer


class SnippetViewSet(viewsets.ModelViewSet):
    queryset = Snippet.objects.all()
    serializer_class = SnippetSerializer