public static function sendResponseCode($code)
    {
        $messages = array(
            200 => 'Ok',
            204 => 'No Response',
            301 => 'Moved Permanently',
            302 => 'Found',
            304 => 'Not Modified',
            400 => 'Bad Request',
            401 => 'Unauthorized',
            403 => 'Forbidden',
            404 => 'Not Found',
            500 => 'Internal Server Error',
            503 => 'Service Unavailable',
        );

        if (!array_key_exists($code, $messages)) {
            throw new Exception('Response code not supported: ' . $code);
        }

        if (strpos(PHP_SAPI, '-fcgi') === false) {
            $key = 'HTTP/1.1';

            if (array_key_exists('SERVER_PROTOCOL', $_SERVER)
                && strlen($_SERVER['SERVER_PROTOCOL']) < 15
                && strlen($_SERVER['SERVER_PROTOCOL']) > 1) {
                $key = $_SERVER['SERVER_PROTOCOL'];
            }
        } else {
            // FastCGI
            $key = 'Status:';
        }

        $message = $messages[$code];
        Common::sendHeader($key . ' ' . $code . ' ' . $message);
    }