Following this discussion i can't figure it out how to getUserId from session or how to create session from a signed request in new SDK 4 for PHP? I'm trying to migrate my apps from old SDK to new one and my code doesn't work well. I'm trying to get the user ID on page tab where i'm an admin. I've tried to getSession from FacebookPageTabHelper with no luck.
My php code:
session_start();
require_once '../api/facebook/autoload.php';
use Facebook\FacebookSession;
use Facebook\FacebookPageTabHelper;
FacebookSession::setDefaultApplication(APP_ID, APP_SECRET);
$pageHelper = new FacebookPageTabHelper();
$page = $pageHelper->getPageId();
$admin = $pageHelper->isAdmin();
$fan = $pageHelper->isLiked();
$appdata = $pageHelper->getSignedRequest()->payload['app_data'];
$session = $pageHelper->getSession();
$user = $session->getUserId(); // always empty