Horde_Auth_Ldap::exists PHP Method

    public function exists($userId)
    {
        $params = array('scope' => $this->_params['scope']);
        try {
            $uidfilter = Horde_Ldap_Filter::create($this->_params['uid'], 'equals', $userId);
            $classfilter = Horde_Ldap_Filter::build(array('filter' => $this->_params['filter']));
            $search = $this->_ldap->search($this->_params['basedn'], Horde_Ldap_Filter::combine('and', array($uidfilter, $classfilter)), $params);
            if ($search->count() < 1) {
                return false;
            }
            if ($search->count() > 1 && $this->_logger) {
                $this->_logger->log('Multiple LDAP entries with user identifier ' . $userId, 'WARN');
            }
            return true;
        } catch (Horde_Ldap_Exception $e) {
            if ($this->_logger) {
                $this->_logger->log('Error searching LDAP user: ' . $e->getMessage(), 'ERR');
            }
            return false;
        }
    }