import ldap
from django.contrib.auth.models import User
from django.contrib.auth.backends import ModelBackend

LDAP = 'ldaps://edir.domain.com:636'
ldap.set_option(ldap.OPT_X_TLS_REQUIRE_CERT, ldap.OPT_X_TLS_NEVER)
ldap.set_option(ldap.OPT_REFERRALS, 0)

class LDAPBackend(ModelBackend):

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

    def authenticate(self, username=None, password=None):
        if not username and not password:
            return None

        ldapuser = "cn="+ username +",ou=users,o=domain"
        try:
            l = ldap.initialize(LDAP)
            l.simple_bind_s(ldapuser,password)
        except ldap.LDAPError:
            return None

        try:
            return User.objects.get(username__exact=username)
        except:
            user = User(username=username)
            user.is_staff = False
            user.is_active = True
            user.is_superuser = False
            user.set_unusable_password()
            user.save()
            return user

        return None