def update 创建一个新的但不更新 - Django

问题描述

我有一种方法可以在我的数据库中创建一个新项目，效果很好。但是更新的类似方法是创建一个新项目而不是更新，如果我强制id传入“data”，它会抱怨这个id已经存在......

我的代码：

class EventsAttachViewSet(
    mixins.ListModelMixin,mixins.CreateModelMixin,mixins.UpdateModelMixin,mixins.DestroyModelMixin,mixins.RetrieveModelMixin,viewsets.GenericViewSet
):
    permission_classes = [permissions.AllowAny]
    queryset = EventAttachment.objects.all()
    serializer_class = EventAttachmentSerializer

    def create(self,request,*args,**kwargs):
        serializer = self.get_serializer(data=request.data)
        serializer.is_valid(raise_exception=True)
        data = serializer.validated_data
        self.perform_create(serializer)
        headers = self.get_success_headers(serializer.data)
        return Response(serializer.data,status=status.HTTP_201_CREATED,headers=headers)

    def update(self,**kwargs):
        serializer = self.get_serializer(data=request.data)
        serializer.is_valid(raise_exception=True)
        data = serializer.validated_data
        self.perform_update(serializer)
        headers = self.get_success_headers(serializer.data)
        return Response(serializer.data,headers=headers)

解决方法

这里你需要传递一个对象的实例来进行更新。

def update(self,request,*args,**kwargs):
        instance = self.get_object()
        serializer = self.get_serializer(instance,data=request.data)
        serializer.is_valid(raise_exception=True)
        data = serializer.validated_data
        self.perform_update(serializer)
        headers = self.get_success_headers(serializer.data)
        return Response(serializer.data,status=status.HTTP_201_CREATED,headers=headers)