Django language set in the database field applied on login

In one of my Django projects available only for logged in users I needed to set language setting in the database, so user can change the language setting in his profile.

Here comes a handy "user_logged_in" (Django >= 1.3) signal which lets us do things after user is logged in. In our case, we modify session and change the language.

My user_details.models.py:

from django.dispatch import receiver
from django.contrib.auth.signals import user_logged_in
from django.utils.translation import ugettext_lazy as _
from django.db import models
from django.conf import settings

class UserProfile(models.Model):
    user = models.OneToOneField(User, blank=Flse)
    language = models.CharField(verbose_name=_(u"Interface Language"), 
                   max_length=4, choices=settings.LANGUAGES)

@receiver(user_logged_in)
def lang(sender, **kwargs):
    lang_code = kwargs['user'].userprofile.language
    kwargs['request'].session['django_language'] = lang_code

settings.py

gettext = lambda s: s

LANGUAGES = (
    ('pl',gettext('Polski')),
    ('en',gettext('English')),
    ('de',gettext('Deutsch')),
)