python - 如何解决错误 "object_permission() takes 3 positional arguments but 4 were given"？

Question

我正在尝试实现对象级权限。当我运行我的代码时，我收到一条错误消息，指出我使用了太多位置参数。

TypeError: has_object_permission() takes 3 positional arguments but 4 were given

但是，当我查看 Django Rest 框架的文档时，也使用了四个参数。

class PostOwnerPermssion(permissions.BasePermission):
    """
    Check if authenticated user is  story author
    """
    def has_object_permission(self,request,obj,**kwargs):
        if request.user.id == story.author:
            return True
        return False

我很高兴得到任何澄清。

谢谢。

Answer 1

However, when I check the documentation for the Django Rest framework, four arguments are also used.

class PostOwnerPermssion(permissions.BasePermission):
    """
    Check if authenticated user is  story author
    """
    def has_object_permission(self,request,obj,**kwargs):
        if request.user.id == story.author:
            return True
        return False

否，**kwargs与任意数量的named 参数匹配，因此您可以使用 my_post_owner_permssion.has_object_permission(request, some_obj<b>, foo=bar, qux=bar2</b>)` 调用它但不位置参数(没有名称的参数)。

您可以实现以下一种(或两种)方法:

1. .has_permission(self, request, view) ;和
2. .has_object_permission(self, request, view, obj)

您的案例中缺少的是 view参数，因此您可以将其重写为:

class PostOwnerPermssion(permissions.BasePermission):
    """
    Check if authenticated user is  story author
    """
    def has_object_permission(self, request, <b>view</b>, obj):
        return <b>request.user.id == obj.author_id</b>