python通过扩展manage.py的视图导致AppRegistryNotReady异常

Question

环境：

• Ubuntu GNOME 14.04
• Python2.7.6(使用虚拟环境)
• Django 1.7.1 (在虚拟环境中)
• 自定义用户模型
• django-oauth工具包0.7.2 (通过pip安装) (https://github.com/evonove/django-oauth-toolkit)
• 日食开普勒SR2 (构建id 20140224-0627)
• PyDev 3.8.0.201409251235

我正在使用Django和django-oauth工具包为iOS和安卓应用程序创建一个iOS后端API。我以前在CentOS 6.5上使用Python2.6.6和Django 1.4.8成功地完成了不同的移动应用程序，但是在当前的环境中遇到了麻烦。

我有一个类扩展了django-oauth-工具箱的ProtectedResourceView (http://django-oauth-toolkit.readthedocs.org/en/0.7.2/views/details.html#generic)：

from oauth2_provider.views.generic import ProtectedResourceView
from django.http.response import HttpResponse

class TestEndpoint(ProtectedResourceView):

    def get(self, request, *args, **kwargs):
        return HttpResponse("Hello World!")

此视图的文件位于/home/user/workspace/MyProject/MyApp/views/test_endpoint.py中。它被导入到/home/user/workspace/MyProject/MyApp/views/__init__.py中的视图包中。

端点映射到我的urls.py中：

from django.conf.urls import patterns, url
from MyApp.views import UnprotectedEndpoint
from MyApp.views.test_endpoint import TestEndpoint

urlpatterns = patterns('api_v1',
    url(r'^account/create/', UnprotectedEndpoint.as_view()),
    url(r'^test/', TestEndpoint.as_view()),
)

输入virtualenv后，我运行python manage.py runserver并获得以下错误：

(MyVirtualEnv)user@ubuntu-laptop:~/workspace/MyProject$ python manage.py runserver
Traceback (most recent call last):
  File "manage.py", line 10, in <module>
    execute_from_command_line(sys.argv)
  File "/home/user/virtualenvs/MyVirtualEnv/local/lib/python2.7/site-packages/django/core/management/__init__.py", line 385, in execute_from_command_line
    utility.execute()
  File "/home/user/virtualenvs/MyVirtualEnv/local/lib/python2.7/site-packages/django/core/management/__init__.py", line 354, in execute
    django.setup()
  File "/home/user/virtualenvs/MyVirtualEnv/local/lib/python2.7/site-packages/django/__init__.py", line 21, in setup
    apps.populate(settings.INSTALLED_APPS)
  File "/home/user/virtualenvs/MyVirtualEnv/local/lib/python2.7/site-packages/django/apps/registry.py", line 85, in populate
    app_config = AppConfig.create(entry)
  File "/home/user/virtualenvs/MyVirtualEnv/local/lib/python2.7/site-packages/django/apps/config.py", line 87, in create
    module = import_module(entry)
  File "/usr/lib/python2.7/importlib/__init__.py", line 37, in import_module
    __import__(name)
  File "/home/user/workspace/MyProject/MyApp/__init__.py", line 1, in <module>
    import urls
  File "/home/user/workspace/MyProject/MyApp/urls.py", line 2, in <module>
    from MyApp.views import UnprotectedEndpoint
  File "/home/user/workspace/MyProject/MyApp/views/__init__.py", line 3, in <module>
    from test_endpoint import TestEndpoint
  File "/home/user/workspace/MyProject/MyApp/views/test_endpoint.py", line 1, in <module>
    from oauth2_provider.views.generic import ProtectedResourceView
  File "/home/user/virtualenvs/MyVirtualEnv/local/lib/python2.7/site-packages/oauth2_provider/views/__init__.py", line 1, in <module>
    from .base import AuthorizationView, TokenView
  File "/home/user/virtualenvs/MyVirtualEnv/local/lib/python2.7/site-packages/oauth2_provider/views/base.py", line 13, in <module>
    from ..forms import AllowForm
  File "/home/user/virtualenvs/MyVirtualEnv/local/lib/python2.7/site-packages/oauth2_provider/forms.py", line 22, in <module>
    class RegistrationForm(forms.ModelForm):
  File "/home/user/virtualenvs/MyVirtualEnv/local/lib/python2.7/site-packages/oauth2_provider/forms.py", line 26, in RegistrationForm
    class Meta:
  File "/home/user/virtualenvs/MyVirtualEnv/local/lib/python2.7/site-packages/oauth2_provider/forms.py", line 27, in Meta
    model = get_application_model()
  File "/home/user/virtualenvs/MyVirtualEnv/local/lib/python2.7/site-packages/oauth2_provider/models.py", line 241, in get_application_model
    app_model = get_model(app_label, model_name)
  File "/home/user/virtualenvs/MyVirtualEnv/local/lib/python2.7/site-packages/django/apps/registry.py", line 199, in get_model
    self.check_models_ready()
  File "/home/user/virtualenvs/MyVirtualEnv/local/lib/python2.7/site-packages/django/apps/registry.py", line 131, in check_models_ready
    raise AppRegistryNotReady("Models aren't loaded yet.")
django.core.exceptions.AppRegistryNotReady: Models aren't loaded yet.

当我将TestEndpoint从__init__.py和urls.py中删除时，服务器就会正常启动。但是，当我导入扩展ProtectedResourceView的视图时，将引发AppRegistryNotReady异常。为什么Django不喜欢那样的景色？

Answer 1

这是与Django 1.7一起使用的django-oauth-toolkit中的一个bug，参见此处：https://github.com/evonove/django-oauth-toolkit/issues/151

您可以使用发布到该问题的解决方案，或者只需切换回Django 1.6并等待django-oauth-toolkit的修复。

==========

从OP更新

此问题已在django-oauth工具包0.8中得到解决，并于2015年3月27日发布到PyPI。我已经用原问题中描述的项目测试并证实了这一点。