public function serviceValidate($service, $ticket, $timeout = 10)
    {
        header('Content-Type: text/xml; charset=UTF-8');
        exit(self::file_get_contents($this->server['service_validate_url'] . '?' . http_build_query(array(
                'service' => $this->my_service . '?' . http_build_query(array(
                        'service' => $service,
                    )),
                'ticket' => $ticket,
            )), $timeout));
        // never reach
        return true;
    }