django Backend con ldap

backend.py

# -*- coding: utf-8 -*-
""" Metodos de Autentificacion """
from django.contrib.auth.backends import RemoteUserBackend, ModelBackend
from django.contrib.auth.models import User
from mosketeros.settings import LDAP_SERVER,LDAP_BIND,LDAP_SEARCH

class DjangoAuth(ModelBackend):
    """ Autentificacion del framework """
    #create_unknown_user = False
    #supports_anonymous_user = False
    pass
class BackendRemoteUser(RemoteUserBackend):
    """ Autentificacion remota """
    pass


class LdapUserAuth(DjangoAuth):
    """ Autentificacion utilizando LDAP (Active Directory)"""
    def check_ldap(self, username):
        """ Checar  si el usuario existe en ldap 
            @username str nombre de usuario  para checar
        """
        import ldap
        ldap_client  = ldap.initialize(LDAP_SERVER)
        ldap_user,ldap_pass = LDAP_BIND
        ldap_client.simple_bind(ldap_user,ldap_pass)
        self._result(ldap_client)

        str_search, user_to_search = LDAP_SEARCH
        ldap_client.search(str_search ,ldap.SCOPE_SUBTREE,user_to_search % username)
        id,res = self._result(ldap_client)
        if len(res) > 0:
            # Pertenece a ldap
            return True
        else:
            return False
    def auth_ldap(self,username,password):
        """ Autentificacion para ldap 
            @username str  usuario de LDAP
            @password str  contraseña de LDAP
        """
        import ldap
        ldap_client = ldap.initialize(LDAP_SERVER)
        try:
            ldap_client.simple_bind(username,password)
        except ldap.SERVER_DOWN:
            return False
        except UnicodeEncodeError:
            return False
        try:
            ldap_client.result()
            return True
        except ldap.INVALID_CREDENTIALS:
            return False

    def _result(self, ldap_client):
        """ Checar el resultado de autenficacion
            @ldap_client obj cliente de ldap
        """
        try:
            return    ldap_client.result()
        except ldap.INVALID_CREDENTIALS :
            return False
    def authenticate(self, username, password ):
        """ Metodo de autentificacion del backend
            @username str usuario 
            @password str contraseña
        """
        success = self.auth_ldap(username,password)
        if not success:
            return None
        else:
            try:
                user = User.objects.get(username = username)
                return user
            except User.DoesNotExist:
                return None