public function authenticate()
{
$identity = $this->em->find('Newscoop\\Entity\\UserIdentity', array('provider' => $this->provider, 'provider_user_id' => $this->providerUserId));
if (empty($identity)) {
return new \Zend_Auth_Result(\Zend_Auth_Result::FAILURE_IDENTITY_NOT_FOUND, NULL);
}
return new \Zend_Auth_Result(\Zend_Auth_Result::SUCCESS, $identity->getUser()->getId());
}