Question

使用模型

class PlanSerializer(serializers.ModelSerializer):

    class Meta:
        model = Plan
        fields = ("id", "name", "amount")

使用ListAPIView（因为只有/ GET /操作在此资源上有效）

class PlanList(generics.ListAPIView):
    queryset = Plan.objects.all()
    serializer_class = PlanSerializer

/ GET /

  [
        {
            "id": 4, 
            "name": "free", 
            "amount": 110.0
        }, 
        {
            "id": 3, 
            "name": "permium", 
            "amount": 60.0
        }
    ]

在响应中有一个常量值DISCOUNT，它应该只在响应中出现一次，因此响应看起来像

  [
        {
            "id": 4, 
            "name": "free", 
            "amount": 110.0
        }, 
        {
            "id": 3, 
            "name": "permium", 
            "amount": 60.0
        },
       {"DISCOUNT": 210}
    ]

我尝试将此折扣作为属性并在序列化程序中使用它但是每个实例都重复这个，我希望它只出现一次。

对此有何想法？

Answer 1

您可以从list method覆盖ListAPIView。将CONSTANT附加到最终的序列化数据。

class PlanList(generics.ListAPIView):
    queryset = Plan.objects.all()
    serializer_class = PlanSerializer

    def list(self, request, *args, **kwargs):
        queryset = self.filter_queryset(self.get_queryset())

        page = self.paginate_queryset(queryset)
        if page is not None:
            serializer = self.get_serializer(page, many=True)
            return self.get_paginated_response(serializer.data)

        serializer = self.get_serializer(queryset, many=True)
        #add your constant here
        final_response = serializer._data.copy()
        final_response["DISCOUNT"] = 210
        return Response(final_response)

Answer 2

要向ModelSerializer回复添加另一个字典，您可以覆盖list()视图的PlanList方法。

class PlanList(generics.ListAPIView):
    queryset = Plan.objects.all()
    serializer_class = PlanSerializer

    def list(self, request, *args, **kwargs):
        instance = self.filter_queryset(self.get_queryset())
        page = self.paginate_queryset(instance)
        if page is not None:
            serializer = self.get_pagination_serializer(page)
        else:
            serializer = self.get_serializer(instance, many=True)

        serializer_data = serializer.data # get the default serialized data 
        serializer_data.append({"DISCOUNT": 210}) # add a custom dictionary in the response
        return Response(serializer_data)

然后，您的回答将类似于：

 [
        {
            "id": 4, 
            "name": "free", 
            "amount": 110.0
        }, 
        {
            "id": 3, 
            "name": "permium", 
            "amount": 60.0
        },
       {
            "DISCOUNT": 210
       }
    ]

如何将键值添加到ModelSerilzer响应中

2 个答案: