Facebook events graph not working

Question

I'm trying to get an Facebook page events. I've checked that the app id and app secret are correct and I still keep getting the error.

<?php
ini_set('display_startup_errors',1);
ini_set('display_errors',1);
error_reporting(-1);

ob_start();

require 'facebook/src/facebook.php';

$fb = new Facebook(array(
       'appid'=>'APPID',
       'secret'=>'APPSECRET'
      ) );
$page_events = $fb->api('/PAGEID/events?fields=description,location,name,owner,cover,start_time,end_time', 'GET');
printf ('<pre>%s</pre>', $page_events);

?>

The error message:

Uncaught OAuthException: Invalid OAuth access token signature. thrown in

Answer 1

I'm not sure you've implemented or not but your code is missing-

1. User Login/Authentication

   The code is not authenticating the user. After creating the $fb object; use this-

   $user_id = $fb->getUser();
   if($user_id) {
      try {
   
         // proceed your api calls - user is authenticated at this point
   
      } catch(FacebookApiException $e) {
         $login_url = $fb->getLoginUrl(array( 'scope' => 'manage_pages'));
         header ("Location: $login_url");
         error_log($e->getType());
         error_log($e->getMessage());
      }   
   } else {
      $login_url = $fb->getLoginUrl(array( 'scope' => 'manage_pages'));
      header ("Location: $login_url");
   }
   

2. Permissions

   The documentation says-

   For the page events-

   • Any access token can be used to view publicly shared events.
   • A user access token is required to retrieve events visible to that person.
   • A page access token is required to retrieve any other events.

   I think you are trying to fetch all the events in a page, so you'll be needing the page access token.

   To get a page access token: $fb->api("/PAGE_ID?fields=access_token");. Use the token return with your original call to get all the page's events-

   $page_events = $fb->api('/PAGEID/events?access_token='.$page_access_token.'&fields=description,location,name,owner,cover,start_time,end_time', 'GET');
   

(If required, you can also get a never expiring page token for a page: See here)