SimpleMachines forum authentication backend

import hashlib
from string import lower
from django.contrib.auth.models import User
from yourproject import settings

class SMFBackend:
    """
    Django authentication backend for SimpleMachines Forum user database.
    (For more information on SMF go to http://simplemachines.org/)

    Also it fetches e-mail address from SMF user profile and updates Django user profile on every login.
    """
    def authenticate(self, username=None, password=None):
        valid = False
        email = None

        if not (username is None) and not (password is None):
            hash = hashlib.sha1(lower(username) + password).hexdigest()

            from django.db import connection
            cursor = connection.cursor()
            cursor.execute("select passwd, ID_GROUP, emailAddress from %s_members where memberName = '%s' and is_activated = '1'" % (settings.SMF_PREFIX, username))
            row = cursor.fetchone()
            email = row[2]
            
            if row[0] == hash:
                valid = True

            if hasattr(settings, 'SMF_GROUP') and (settings.SMF_GROUP != row[1]):
                valid = False

        if valid:
            try:
                user = User.objects.get(username=username)
            except User.DoesNotExist:
                user = User(username=username)
                user.is_staff = True
                user.is_superuser = False
                user.set_unusable_password() # disable login through Model backend
                user.save()
            if not email is None:
                user.email = email
            return user
        return None

    def get_user(self, user_id):
        try:
            return User.objects.get(pk=user_id)
        except User.DoesNotExist:
            return None