Django 1.5: Accessing custom user model fields in models.py

问题

I'm working on a Django 1.5 project and I have a custom user model (let's call it CustomUser). Another app (SomeApp) needs to reference this custom user model. For the purposes of ForeignKey and such, the Django documentation says to use

User = settings.AUTH_USER_MODEL

However, some functions in SomeApp.models need to access what would have formerly been known as User.objects. But User is now a string and not a class, so User.objects fails. The alternative would be

from django.contrib.auth import get_user_model
User = get_user_model()

Which works in other modules, but when I use this in models.py of SomeApp, Django raises an error:

ImproperlyConfigured("AUTH_USER_MODEL refers to model '%s' that has not been installed" % settings.AUTH_USER_MODEL)

Any ideas?

EDIT 1 - Traceback:

Traceback (most recent call last):
  File "<console>", line 1, in <module>
  File "...\django-badger\badger\__init__.py", line 7, in <module>
    from badger.models import Badge, Award, Progress
  File "...\django-badger\badger\models.py", line 26, in <module>
    User = get_user_model()
  File "...\lib\site-packages\django\contrib\auth\__init__.py", line 127, in get_user_model
    raise ImproperlyConfigured("AUTH_USER_MODEL refers to model '%s' that has not been installed" % settings.AUTH_USER_MODEL)
ImproperlyConfigured: AUTH_USER_MODEL refers to model 'MyApp.AuthUser' that has not been installed

EDIT 2 - INSTALLED_APPS settings:

INSTALLED_APPS = (
'django.contrib.auth',
'django.contrib.contenttypes',
'django.contrib.sessions',
'django.contrib.sites',
'django.contrib.messages',
'django.contrib.staticfiles',
'django.contrib.admin',
'django.contrib.admindocs',
'south',
'MyApp',   # this is where my user model is defined
'SomeApp', # I try to use get_user_model() in this app's models.py; doesn't work.
'social_auth',
)

回答1:

Easy one, I think. I have had so many problems with recursive inclusions and so on... Well, the simplest thing to do, when you add a ForeignKey, is to write it like so:

user = models.ForeignKey(settings.AUTH_USER_MODEL, null=False, on_delete=models.CASCADE, verbose_name=_(u"User"))

If you use get_user_model, do not use it like you do. Calling

User = get_user_model()

at the top of the module will try to import your User model, which may, indeed, not have been "installed". Instead, you have several choices:

At the top of your module, write

User = get_user_model # then, you will have to use User() instead of User
Write get_user_model() everywhere it's useful. Always in methods or functions, never directly in a model module body.

回答2:

I had the same problem just now and here is my 2 cents/solution.

If you want to use custom user model in models.py you'll be using for foreign keys settings.AUTH_USER_MODEL and for model methods you have to use get_user_model() but it has to be inside the method. It won't work outside because of circular import.

from django.conf import settings
from django.contrib.auth import get_user_model

class Event(models.Model):

    recipient = models.ForeignKey(settings.AUTH_USER_MODEL)
    ...

    def get_something(self):

        User = get_user_model()
        u = User.objects.get(id=...)
        ...

回答3:

Make sure your custom User model is not abstract.

回答4:

I think this import from SomeApp makes a circular import. That's why there is a statement in docs to do something like ForeignKey with calling settings attribute.

As for me, I have encountered with this thing when I used django-filer app. There was a commit on github to prevent imports with get_user_model(). You can use the code there like an example to fix the problem.

This problem is very tricky, because when you try to call get_user_model() from shell - it would work.

回答5:

The Django documentation has the answer: https://docs.djangoproject.com/en/dev/topics/auth/customizing/#django.contrib.auth.get_user_model

The most relevant section: Generally speaking, you should reference the User model with the AUTH_USER_MODEL setting in code that is executed at import time. get_user_model() only works once Django has imported all models.

The real solution is to make sure that you only use get_user_model() inside of a method, so that it won't get executed at import time.

回答6:

You have to set,

AUTH_USER_MODEL = "yourapp.CustomUser"

in the settings.py. Then the get_user_model() will work. There is a clean documentation available.

回答7:

I'm starting to think a workaround might be in order - any comments on the following in SomeApp/models.py:

from django.contrib.auth.models import User as UserModel
try:
    from django.contrib.auth import get_user_model
except ImportError:  #django <= 1.4 doesn't have get_user_model so define our own
    def get_user_model():
        return UserModel
User = getattr(settings, 'AUTH_USER_MODEL', 'auth.User')
...
def SomeModel(models.Model):
    user = models.ForeignKey(User)  # using the name of the model
    def some_method(self, email):
        qs = get_user_model().objects.filter(email=email)  # using function call to get model class