django-restframework view中的内容

from rest_framework import generics
from rest_framework import permissions
from rest_framework.filters import OrderingFilter, SearchFilter
from rest_framework.pagination import LimitOffsetPagination

# 第四层方式，使用的最多
class ProductListByCategoryView(generics.ListAPIView):  
    '''
    产品按类别列表
    '''
    serializer_class = ProductListSerializer
    # 允许访问权限      permissions.AllowAny 允许所有人访问
    permission_classes = (permissions.AllowAny,)
    # 对列表进行排序(restframework生成的排序列表,通过get方式的ordering传递)  SearchFilter(搜索功能)
    filter_backends = (OrderingFilter, SearchFilter)
    # 排序方式 
    ordering_fields = ('category', 'manufacturer', 'created', 'sold')
    # 搜索字段
    search_fields = ('description', 'model')
    # 默认排序
    ordering = ('id',)
    # 用于前端指定一页数据显示多少条内容
    pagination_class = LimitOffsetPagination

    def get_queryset(self):
　　　　　# 此方法用于判断前端是否传递内容，如果没传递，则默认查询所有， 如果传递了，则按要求进行查询
        category = self.request.query_params.get('category', None)

        if category is not None:
            queryset = Product.objects.filter(category=category)
        else:
            queryset = Product.objects.all()
        return queryset


# 第三层使用方法  有时需求不能按照model进行，则需要第三层的方式进行优化

# class SnippetList(APIView):
#     '''
#     LC （查询以及增加）
#     '''
#     def get(self,request, format=None):
#         snippets = Snippet.objects.all()
#         serializer = SnippetSerializer(snippets, 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 SnippetDetail(APIView):
#     '''
#     RUD
#     '''
#     def get_object(self,pk):
#         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)
#
#     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)