#signals.py
from django.dispatch import Signal

post_login = Signal(providing_args=['user'])


#auth_backends.py
from django.contrib.auth.backends import ModelBackend
from django.contrib.auth.models import User
from project.signals import post_login

class CustomBackend(ModelBackend):
    def authenticate(self, username=None, password=None):
        try:
            user = User.objects.get(username=username)
            if user.check_password(password):
                post_login.send(sender=None, user=user)
                return user
        except User.DoesNotExist:
            return None

# listeners.py
from project.signals import post_login

def login_handler(sender, **kwargs):
    **# do some voodoo**
    return

post_login.connect(login_handler)