视图集

两个视图基类

1.drf提供了一个顶层的视图APIView，可以通过继承APIView写视图，之后我们写的代码可能重复代码比较多，就可以使用面向对象的继承、封装，GenericAPIView继承了APIView，我们用GenericAPIView时就不需要继承APIView

2.GenericAPIView的属性和方法
2.1属性
-queryset
要序列化的数据
-serializer_class
序列化类
-lookup_field
通过get_object获取单个对象的查询key值，value值是由路由中传进来的
-filter_backends
过滤器
-pagination_class
分页器

2.2方法
-get_queryset
获取要序列化的数据
-get_object
根据lookup_field配置的参数获取一条数据
-get_serializer
获取序列化类，我们直接使用
-get_serializer_class
获取序列化类，不是我们直接使用的，它在get_serializer里调用了它
-filter_queryset
跟过滤有关系
-paginate_xxx
跟分页有关系

5个视图扩展类写接口

'必须配合GenericAPIView使用'
from rest_framework.mixins import ListModelMixin, CreateModelMixin, RetrieveModelMixin, UpdateModelMixin, DestroyModelMixin
'''
ListModelMixin:写了list方法，就是我们原来的获取所有数据的get中的代码
CreateModelMixin:写了create方法，就是我们原来的post中的代码
RetrieveModelMixin:写了retrieve方法，就是我们原来的获取单条数据的get中的代码
UpdateModelMixin:写了update方法，就是我们原来的put中的代码
DestroyModelMixin:写了destroy方法，就是我们原来的delete中的代码
'''

class BookView(GenericAPIView, ListModelMixin, CreateModelMixin):
    queryset = Book.objects.all()
    serializer_class = BookModelSerializer

    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 BookDataView(GenericAPIView, RetrieveModelMixin, UpdateModelMixin, DestroyModelMixin):
    queryset = Book.objects.all()
    serializer_class = BookModelSerializer

    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)

9个视图子类写接口

'视图类继承GenericAPIView+某个某几个视图扩展类'
from rest_framework.mixins import ListModelMixin, CreateModelMixin, RetrieveModelMixin, UpdateModelMixin, DestroyModelMixin
from rest_framework.generics import ListCreateAPIView, RetrieveUpdateDestroyAPIView, RetrieveUpdateAPIView, RetrieveDestroyAPIView
'没有Update+Destroy'

class BookView(ListCreateAPIView):
    queryset = Book.objects.all()
    serializer_class = BookModelSerializer


class BookDataView(RetrieveUpdateDestroyAPIView):
    queryset = Book.objects.all()
    serializer_class = BookModelSerializer

视图集

继承ModelViewSet编写5个接口

1.视图类
from rest_framework.viewsets import ModelViewSet, ReadOnlyModelViewSet
'ReadOnlyModelViewSet只能查询一个或查询所有'

class BookView(ModelViewSet):
    queryset = Book.objects.all()
    serializer_class = BookModelSerializer

2.路由
urlpatterns = [
    path('admin/', admin.site.urls),
    path('book/', BookView.as_view({'get': 'list', 'post': 'create'})),
    path('book/<str:pk>/', BookView.as_view({'get': 'retrieve', 'put': 'update', 'delete': 'destroy'})),
]

ViewSetMixin源码

# ViewSetMixin:它控制了路由的写法变了
# ViewSet:APIView+ViewSetMixin的组合
# GenericViewSet:GenericAPIView+ViewSetMixin的组合
'''
ModelViewSet---继承了下面一堆，在路由中配置as_view，执行的就是ViewSetMixin的as_viewViewSetMixin的as_view
mixins.CreateModelMixin,
mixins.RetrieveModelMixin,
mixins.UpdateModelMixin,
mixins.DestroyModelMixin,
mixins.ListModelMixin,
GenericViewSet
'''

-在ViewSetMixin里的as_view中
@classonlymethod
def as_view(cls, actions=None, **initkwargs):
    # 路由中as_view中必须传参数，必须传字典：{'get': 'list', 'post': 'create'}
    if not actions:
        raise TypeError("The `actions` argument must be provided when "
                        "calling `.as_view()` on a ViewSet. For example "
                        "`.as_view({'get': 'list'})`")
-路由匹配成功，执行view(request)，request是老的request
        def view(request, *args, **kwargs):
        	    # actions是字典:{'get': 'list', 'post': 'create'}
                for method, action in actions.items():
                    # method:get	action:list
                    # self是视图类的对象中通过反射，查找list
                    # handler是视图类中的list方法
                    handler = getattr(self, action)
                    # 向视图类的对象中反射method(get),handler:(list)方法
                    # self.get=list
                    setattr(self, method, handler)
                return self.dispatch(request, *args, **kwargs)
        return csrf_exempt(view)
'''
只要继承了ViewSetMixin，以后路由写法变量，都要写成:
BookView.as_view({'get': 'list', 'post': 'create'})
这样写好后，对应请求方式来了，就会执行配置的方法
'''
# 视图类中继承了ViewSetMixin，就可以写任意名字的方法，不用非得写get...

总

1.APIView:它有as_view,dispatch

2.GenericAPIView:继承了APIView，他有类属性和方法

3.5个视图扩展类:ListModelMixin, CreateModelMixin, RetrieveModelMixin, UpdateModelMixin, DestroyModelMixin
-每个类里有一个方法

4.9个视图扩展类

ListModelMixin, CreateModelMixin, RetrieveModelMixin, UpdateModelMixin, DestroyModelMixin
from rest_framework.generics import ListCreateAPIView, RetrieveUpdateDestroyAPIView, RetrieveUpdateAPIView, RetrieveDestroyAPIView