setAuthConfig('credentials.json'); //Download from Google Cloud Admin Pannel $client->setRedirectUri('/oauth2callback.php'); $client->addScope(Google_Service_Calendar::CALENDAR); $client->setAccessType('offline'); if (!isset($_GET['code'])) { die('Kein Code erhalten.'); } $token = $client->fetchAccessTokenWithAuthCode($_GET['code']); $_SESSION['access_token'] = $token; header('Location: index.php'); exit;