Django Multisite User Model

README.md

This code is a sample for a question on Stackoverflow about making multisite user models with Django 1.7.

Usage:

Add these lines to your settings file:

AUTH_USER_MODEL='s1.Member'
SITE_ID = 1
AUTHENTICATION_BACKENDS = ( 'MyApp.MyModule.MyModelBackend',)

models.py

from django.db import models
from django.contrib.auth.models import AbstractUser, UserManager
from django.contrib.sites.models import Site
from django.contrib.sites.managers import CurrentSiteManager
from django.conf import settings

class MemberManager(UserManager):
    def create_user(self, username, **kwargs):
        return super(MemberManager, self).create_user(self, username, **kwargs)

    def create_superuser(self, username, **kwargs):
        return super(MemberManager, self).create_superuser(self, username, **kwargs)


class Member(AbstractUser):
    site = models.ForeignKey(Site, null=True)

    USERNAME_FIELD = 'username'
    REQUIRED_FIELDS = []

    default_manager = MemberManager()
    on_site = CurrentSiteManager()

    class Meta:
        unique_together = ('site', 'email')


from django.db.models.signals import pre_save
from django.dispatch import receiver

@receiver(pre_save, sender=Member)
def compose_username(sender, instance, **kwargs):
    site_id = instance.site_id or 1
    instance.username = "{0}__{1}".format( instance.email, site_id )
    instance.site = Site.objects.get_current()

from django.contrib.auth.backends import ModelBackend
from django.contrib.auth import get_user_model

class MyModelBackend(ModelBackend):

    def authenticate(self, username=None, password=None, **kwargs):
        UserModel = get_user_model()
        site = kwargs.get('site', settings.SITE_ID)
        identifier = "{0}__{1}".format( username, site )

        try:
            user = UserModel.objects.get(username=identifier)

            if user.check_password(password):
                return user

        except UserModel.DoesNotExist:
            UserModel().set_password(password)

        return None