Django REST Framework：“BasePermissionMetaclass”对象不可迭代

Python/Django n00b 从 javascript 转移过来。

尝试使用 Django REST Framework 添加 API 端点，我希望最终能够使用 PATCH 请求的正文更新用户，但现在我只希望它不要抛出 500 错误。

我已将其添加到 urlpatterns 中：

url(r'update/$', views.UpdateView.as_view(), name="update_user"),

这应该带来这样的观点：

from django.contrib.auth.models import User
from rest_framework.generics import UpdateAPIView
from .serializers import UserSerializer

class UpdateView(UpdateAPIView):
    queryset = User.objects.all()
    serializer_class = UserSerializer

UserSerializer 看起来像这样：

class UserSerializer(serializers.ModelSerializer):
    class Meta:
        model = User
        fields = ('username', 'pk', 'status')

似乎每次我访问路线时都会得到这个：

TypeError at /api/update/
'BasePermissionMetaclass' object is not iterable

我不知道我在做什么——以前有人见过这个吗？

更新：完整回溯：

Internal Server Error: /api/update/
Traceback (most recent call last):
  File "path/to/myapp/env/lib/python2.7/site-packages/django/core/handlers/exception.py", line 41, in inner
    response = get_response(request)
  File "path/to/myapp/env/lib/python2.7/site-packages/django/core/handlers/base.py", line 187, in _get_response
    response = self.process_exception_by_middleware(e, request)
  File "path/to/myapp/env/lib/python2.7/site-packages/django/core/handlers/base.py", line 185, in _get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)
  File "path/to/myapp/env/lib/python2.7/site-packages/django/views/decorators/csrf.py", line 58, in wrapped_view
    return view_func(*args, **kwargs)
  File "path/to/myapp/env/lib/python2.7/site-packages/django/views/generic/base.py", line 68, in view
    return self.dispatch(request, *args, **kwargs)
  File "path/to/myapp/env/lib/python2.7/site-packages/rest_framework/views.py", line 495, in dispatch
    response = self.handle_exception(exc)
  File "path/to/myapp/env/lib/python2.7/site-packages/rest_framework/views.py", line 455, in handle_exception
    self.raise_uncaught_exception(exc)
  File "path/to/myapp/env/lib/python2.7/site-packages/rest_framework/views.py", line 483, in dispatch
    self.initial(request, *args, **kwargs)
  File "path/to/myapp/env/lib/python2.7/site-packages/rest_framework/views.py", line 401, in initial
    self.check_permissions(request)
  File "path/to/myapp/env/lib/python2.7/site-packages/rest_framework/views.py", line 333, in check_permissions
    for permission in self.get_permissions():
  File "path/to/myapp/env/lib/python2.7/site-packages/rest_framework/views.py", line 280, in get_permissions
    return [permission() for permission in self.permission_classes]
TypeError: 'BasePermissionMetaclass' object is not iterable

您输错了逗号DEFAULT_PERMISSION_CLASSESvalue，因此 Django 将其视为字符串，而不是元组。

Solution:

REST_FRAMEWORK = {
   ...
   'DEFAULT_PERMISSION_CLASSES': ( 'rest_framework.permissions.IsAdminUser', ),
   ...
}