03_Tutorial 3: Class-based Views 基于类的视图（CBV）

1、CBV

0、文档

https://q1mi.github.io/Django-REST-framework-documentation/tutorial/3-class-based-views_zh/

https://www.django-rest-framework.org/tutorial/3-class-based-views/

1、方式1：APIView

# 方式1：APIView 使用基于类的视图重写我们的API
# 使用基于类视图的最大优势之一是它可以轻松地创建可复用的行为

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)

2、方式2：使用混合（mixins）

1、mixin类 和 GenericAPIView类

 mixin类提供.list()和.create()操作

GenericAPIView类来提供核心功能， 继承APIView

2、get_queryset()`/`get_serializer_class()

queryset = None
serializer_class = None

# 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)

3、方式3：使用通用的基于类的视图：generics

1、get、post

class SnippetList(generics.ListCreateAPIView)

2、单个的增删改查

class SnippetDetail(generics.RetrieveUpdateDestroyAPIView)

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