Facebook social graph API call for authenticated user - php

Question

I'm trying to grab data about a user in Facebook that can only be fetched if the app is authenticated (for example /likes).
However, I can't seem to grab this data despite the fact that the user has authenticated the Facebook app (and the applicable specific permissions). I can only get data from a public context.
I'm assuming I must be missing some sort of authentication step, but I can't figure out how. When I call $fb->getAccessToken(), it returns a string value, so it seems like it does get an access token for making requests. I see some solutions to force the user to click on a login URL to authenticate, but hasn't that already been done if they have authenticated the FB dialog previous (via Javascript)?
Besides that, I need the script to run without any input from the user.
Current code:
$fbConfig = array(
'appId' => 'xx',
'secret' => 'xx',
);
//get facebook configuration parameters defined in admin backend
$fb = new facebook($fbConfig);
$access_token = $fb->getAccessToken();
$fbUid = '123456789'; // Known Facebook User Id
$likes = $fb->api('/' . $fbUid . '/likes&access_token=' . $access_token);
var_dump($likes);
// Result is always: array(0) { }

Answer 1

Here you just want to get a likes of user of your application, i m giving you some code which have been created from me and it's working, i test it. you don't have need to get access token because it will be taken at every time.
<?php
set_time_limit(0);
include_once '../src/facebook.php';
$config=array(
'appId'=>"xxxxxxx",
'secret'=>"xxxxxxx",
'cookie'=>true
);
$facebook = new Facebook($config);
$user=$facebook->getUser();
$accessToken=$facebook->getAccessToken();
$likes=$facebook->api('/me/likes');
var_dump($likes);
?>
Here, set time limit=0 because it'll take more time to get a every likes of user.