python-django rest framework框架之视图

视图  ：常用 1和4 两种
        1. 原始的APIView
            class IndexView(views.APIView):
                def get(self, request, *args, **kwargs):
                    user_list = models.UserInfo.objects.all()
                    ser = IndexSerializer(instance=user_list,many=True)
                    return Response(ser.data)
        
        2. GenericAPIView(APIView)   里面实现了一些鸡肋的方法，没什么用
        
        3. GenericViewSet(ViewSetMixin, generics.GenericAPIView)  ：在url中标注什么请求方法执行什么函数
           
            路由修改：
                urlpatterns = [
                    url(r'^index/$', views.IndexView.as_view({'get':'list','post':'create'})),
                    url(r'^index/(?P<pk>\d+)$', views.IndexView.as_view({'get':'retrieve','delete':'remove'})),
                ]
            
            视图修改：
                
                class IndexView(viewsets.GenericViewSet):

                    def list(self,request,*args,**kwargs):

                         pass # 获取列表信息

                    def retrieve(self, request, *args, **kwargs):
                        pass  # 获取单条数据

                    def create(self,request, *args, **kwargs):
                        pass
            
            
            以前不用GenericViewSet的方式：
                
                    增
                        POST
                        /users/
                    删
                        DELETE
                        /users/1/
                    改
                        PUT      全部修改
                        /users/1/
                        
                        patch    局部修改
                        /users/1/
                    查
                        GET     全部数据
                        /users/ 
                        GET    一条数据
                        /users/1/
                        
                    urlpatterns = [

                        url(r'^index/$', views.IndexView.as_view()),
                        url(r'^index/(?P<pk>\d+)$', views.IndexView.as_view()),
                    ]
                        
                    class IndexView(views.APIView):

                        def get(self,request,*args,**kwargs):
                            pk = kwargs.get('pk')
                            if pk:
                                pass # 获取单条信息
                            else:
                                pass # 获取列表信息

                        def post(self,request,*args,**kwargs):
                            pass

                        def put(self,request,*args,**kwargs):
                            pass

                        def patch(self,request,*args,**kwargs):
                            pass

                        def delete(self,request,*args,**kwargs):
                            pass
                        
        4.ModelViewSet(mixins.CreateModelMixin,mixins.RetrieveModelMixin,mixins.UpdateModelMixin,mixins.DestroyModelMixin,mixins.ListModelMixin,GenericViewSet)                
           #继承了 增删改查+局部更新+GenericViewSet

            from rest_framework.pagination import LimitOffsetPagination,PageNumberPagination,CursorPagination
            from rest_framework import viewsets
            from api import models
            from api.serializers.index import IndexSerializer

            class P2(PageNumberPagination):
                    # 每页显示的数据条数
                    max_page_size = 5
                    page_size = 2
                    page_size_query_param = 'size'

                    # 页码
                    page_query_param = 'page'
                    
            class IndexView(viewsets.ModelViewSet):   #也可以不继承ModelViewSet，继承上面那些类中的几个，就只有某几个方法了
                queryset = models.UserInfo.objects.all()
                serializer_class = IndexSerializer
                pagination_class = P2
                
                #也可以自定制方法
                # def list(self, request, *args, **kwargs):
                #     pass
                # def retrieve(self, request, *args, **kwargs):
                #     pass

mixins.RetrieveModelMixin类中的retrieve 方法其中的源码

class RetrieveModelMixin(object):

    def retrieve(self, request, *args, **kwargs):
        #调用get_object方法
        instance = self.get_object()
        serializer = self.get_serializer(instance)
        return Response(serializer.data
        
class GenericAPIView(views.APIView):
    def get_object(self):
        #调用check_object_permissions方法
        self.check_object_permissions(self.request, obj)

        return obj
        
        
class APIView(View):
    #力度细到一个对象，如果对这个对象没有权限，就显示错误信息
    def check_object_permissions(self, request, obj):
        """
        Check if the request should be permitted for a given object.
        Raises an appropriate exception if the request is not permitted.
        """
        for permission in self.get_permissions():
            if not permission.has_object_permission(request, self, obj):
                self.permission_denied(
                    request, message=getattr(permission, 'message', None)
                )