问保存Facebook signed_request？

EN

/**
 * The name of the Cookie that contains the session.
 * @return String the cookie name
 */
protected function getSessionSignedRequestCookieName() {
    return 'fbs_sr_' . $this->getAppId();
}

/**
 * Saves the signed_request as a browser coookie
 * @return void;
 */
protected function saveSignedRequestAsCookie($signedRequest) {
    $cookieName = $this->getSessionSignedRequestCookieName();

    setcookie($cookieName, serialize($signedRequest));
}

/**
 * Returns the SigndRequest from $_COOKIE
 * @return array
 */
public function getSignedRequestFromCookie() {
    $cookieName = $this->getSessionSignedRequestCookieName();

    if(isset($_COOKIE[$cookieName])) {
        $this->signedRequest = $_COOKIE[$cookieName];
        return unserialize($this->signedRequest);
    } else {
        return NULL;
    }
}

/**
 * Returns the data from a signed_request token provided by $_REQUEST or $_SESSION
 * @return array The decoede signed Request
 */
public function getSignedRequest() {
    $signedRequest = parent::getSignedRequest();

    if($signedRequest != NULL) {
        $this->saveSignedRequestAsCookie($signedRequest);
        return $signedRequest;
    } else {
        return $this->getSignedRequestFromCookie();
    }
}