Facebook PHP SDK - 稍后请求其他权限

我使用以下代码来检查用户是否已授予在用户墙上发布的权限。我不想在登录时最初获得此权限，因为根据 facebook 的说法，这是一种不好的做法，因为用户不知道此权限可能用于什么。因此，当用户单击发布到Facebook墙时，我想检查用户是否已经授予了发布权限，如果没有请求权限。我的代码检查我拥有哪些权限，并将其存储在我无权且需要用户提供的权限数组列表中。

问题：但是当我获得网址并单击它时，它只是将我重定向到重定向网址，而不是请求权限。

我的代码如下：

<?php
$permsNeeded = array();
$permsNeeded[] = "email";
$permsNeeded[] = "publish_stream";
require_once( 'includes/Facebook/HttpClients/FacebookHttpable.php' );
require_once( 'includes/Facebook/HttpClients/FacebookCurl.php' );
require_once( 'includes/Facebook/HttpClients/FacebookCurlHttpClient.php' );
require_once( 'includes/Facebook/Entities/AccessToken.php' );
require_once( 'includes/Facebook/Entities/SignedRequest.php' );
require_once( 'includes/Facebook/FacebookSession.php' );
require_once( 'includes/Facebook/FacebookRedirectLoginHelper.php' );
require_once( 'includes/Facebook/FacebookRequest.php' );
require_once( 'includes/Facebook/FacebookResponse.php' );
require_once( 'includes/Facebook/FacebookSDKException.php' );
require_once( 'includes/Facebook/FacebookRequestException.php' );
require_once( 'includes/Facebook/FacebookOtherException.php' );
require_once( 'includes/Facebook/FacebookAuthorizationException.php' );
require_once( 'includes/Facebook/GraphObject.php' );
require_once( 'includes/Facebook/GraphSessionInfo.php' );
use Facebook'HttpClients'FacebookHttpable;
use Facebook'HttpClients'FacebookCurl;
use Facebook'HttpClients'FacebookCurlHttpClient;
use Facebook'Entities'AccessToken;
use Facebook'Entities'SignedRequest;
use Facebook'FacebookSession;
use Facebook'FacebookRedirectLoginHelper;
use Facebook'FacebookRequest;
use Facebook'FacebookResponse;
use Facebook'FacebookSDKException;
use Facebook'FacebookRequestException;
use Facebook'FacebookOtherException;
use Facebook'FacebookAuthorizationException;
use Facebook'GraphObject;
use Facebook'GraphSessionInfo;
FacebookSession::setDefaultApplication("$appid","$appsecret");
$facebook = new FacebookRedirectLoginHelper("$redirectto");
if(isset($_SESSION['token'])){
    $fbsession = new FacebookSession($_SESSION['token']);
    try{
        $fbsession->Validate($id, $secret);
    }catch(FacebookAuthorizationException $e){
        $fbsession = '';
    }
}
if ( isset( $fbsession ) ) {
    $_SESSION['token'] = $fbsession->getToken();
    $request = new FacebookRequest( $fbsession, 'GET', '/me/permissions' );
    $response = $request->execute();
    $graphObject = $response->getGraphObject();
    $totalproperties = count($graphObject->getPropertyNames());
    $permsArray = array();
    for ($i = 0; $i < $totalproperties; $i++) {
        $permsArray[] = $graphObject->getProperty($i)->GetProperty('permission');
    }
    $permsToPrompt = array();
    for ($i = 0; $i < count($permsNeeded); $i++) {
        if (!in_array($permsNeeded[$i],$permsArray)) {
            $permsToPrompt[] = $permsNeeded[$i];
        }
    }
    if (count($permsToPrompt) > 0) {
        $scopeparams = implode(",",$permsToPrompt);
        $params = array(
            'scope' => $scopeparams
        );
        $helper = new FacebookRedirectLoginHelper($weburl);
        $loginUrl = $helper->getLoginUrl($params);
        echo $loginUrl;
        echo "<a href='"$loginUrl'">test</a>";
        //header("Refresh:0;URL=$reloadurl");
    }
    else {
        //Post
    }
}

？>

在回显上，这将返回以下网址

https://www.facebook.com/v2.2/dialog/oauth?client_id={app_id_here}&redirect_uri={redirect_url_is_written_here}&state={some_value_here}&sdk=php-sdk-4.0.12&scope=publish_stream