from rest_framework.views import APIView

from django.http import Http404

class SnippetList31(APIView):

    """

    列出所有的snippets或者创建一个新的snippet。

    """

    def get(self, request, format=None):

        snippets = Snippet.objects.all()

        serializer = SnippetSerializer(snippets, many=True)  # 序列化多个，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)

class SnippetDetail31(APIView):

    """

    检索，更新或删除一个snippet示例。

    """

    def get_object(self, pk):           # 封装

        """queryset实例对象"""

        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, status=status.HTTP_200_OK)

    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)

# 方式2：使用混合（mixins）

from rest_framework import mixins

from rest_framework import generics

class SnippetList32(mixins.ListModelMixin,    # mixin类提供.list()和.create()操作

                  mixins.CreateModelMixin,

                  generics.GenericAPIView):  # GenericAPIView类来提供核心功能， 继承APIView

    # GenericAPIView中，重写view视图需要

    # 用`get_queryset()`/`get_serializer_class()`替代queryset

    # 一次获取queryset，结果会被缓存，可以多次使用

    # queryset = None

    # serializer_class = None

    queryset = Snippet.objects.all()        # queryset实例对象

    serializer_class = SnippetSerializer    # 序列化器

    def get(self, request, *args, **kwargs):        # get绑定到list()

        return self.list(request, *args, **kwargs)

    def post(self, request, *args, **kwargs):       # post绑定到create()

        return self.create(request, *args, **kwargs)

class SnippetDetail32(mixins.RetrieveModelMixin,  # Retrieve 检索某个

                    mixins.UpdateModelMixin,    # update 更新某个

                    mixins.DestroyModelMixin,   # destroy  删除某个

                    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)

from rest_framework import generics

class SnippetList(generics.ListCreateAPIView):      # list create

    queryset = Snippet.objects.all()

    serializer_class = SnippetSerializer

class SnippetDetail(generics.RetrieveUpdateDestroyAPIView):     # 检索，更新，删除

    queryset = Snippet.objects.all()

    serializer_class = SnippetSerializer