Django Rest 框架：AssertionError

Question

我的 Django Rest Framework 有问题，我正在学习为我的 API 设置 权限和关联，因此我无法运行服务器，所以它说 AssertionError: Field(read_only=True) 应该是 ReadOnlyField

我的模型.py

class Task(models.Model):
    owner=models.ForeignKey('auth.User',related_name='tasks')
    completed=models.BooleanField(default=False)
    title=models.CharField(max_length=100)
    description=models.TextField()

serializer.py

class TaskSerializer(serializers.ModelSerializer):
    owner=serializers.Field('owner.username')
    class Meta:
        model = Task
        fields=('title','description','completed','owner ')

permission.py

class IsOwnerOrReadOnly(BasePermission):
    def has_object_permission(self, request, view, obj):
        if request.method is SAFE_METHODS:
            return True

        return obj.owner==request.user

views.py

class TasksMixins(object):
    queryset = Task.objects.all()
    serializer_class=TaskSerializer
    permission_classes=(IsOwnerOrReadOnly,)

    def pre_save(self,obj):
        obj.owner=self.request.user

class TaskList(ListCreateAPIView):
    pass

class TaskDetail(RetrieveUpdateDestroyAPIView):
    pass

我不确定我搞砸了什么。非常感谢任何帮助

Answer 1

IsOwnerOrReadOnly 类试图将属性所有者与登录的用户进行比较，但在您的序列化程序中您只有用户名而不是用户本身，您的序列化程序应该是这样的：

class TaskSerializer(serializers.ModelSerializer):
    owner_username=serializers.Field('owner.username', read_only=True)
    class Meta:
    model = Task
    fields=('title','description','completed','owner', 'owner_username')

您还需要验证对象是否具有所有者属性：

class IsUserOwner(BasePermission):
    def has_object_permission(self, request, view, obj):
        if request.method is SAFE_METHODS:
            if not hasattr(obj, 'owner'):
                return True

            return obj.owner == request.user
        return True

Answer 2

问题可能与owner.username 有关，因为我不知道如何直接更新它。

试试

class TaskSerializer(serializers.ModelSerializer):

    class Meta:
        model = Task
        read_only=('owner.username',)
        fields=('title','description','completed','owner.username')