Post from server to Facebook page with FB’s PHP SDK 4

On my server, I have a PHP script that runs once a day to post a message and a picture to a Facebook page that I administer. Yesterday Facebook upgraded their API to v2, breaking my script that had been running fine since a few years.

Update August 1, 2018: it seems that today Facebook has killed automated posting to pages. I’ll leave this post here for archaeological purposes.

Update August 26, 2018: using a new never expiring token made things work again.

—

This was the error it threw:

[error] => Array
            (
                [message] => The 'manage_pages' permission must be granted before impersonating a user\'s page.
                [type] => OAuthException
                [code] => 190
            )

Which obviously means that the Facebook app I made to perform the task does not have the proper permission.

The app I made is also used for other tasks. In order not to break them, I created a new app and gave it the proper permissions. After that, I needed to get a page access token that never expires. I also upgraded to version 4 of Facebook’s PHP SDK. Here’s what worked for me.

Create app and token

Create a new website app at https://developers.facebook.com/ . Enter your Site URL and App Domains (www.example.com).

Get a short-lived access token via the Graph API Explorer:

• from the Get Token menu, pick Get Access Token.
• in the dialog window, pick manage_pages and publish_pages from the Extended Permissions tab. Facebook will prompt for confirmation.

Copy the token; it’s the short-lived access token with the proper permissions for posting to your page. It’s a pretty long string.

Make a long-lived access token out of the short-lived token. It’s required to create the never-expiring page access token. In the browser that’s logged in to Facebook as app admin, run this script (upload it to your server first…):

<?php
define('FACEBOOK_SDK_V4_SRC_DIR', '/PATH/TO/fb/src/Facebook/'); 
require 'fb/autoload.php'; 
use Facebook\FacebookSession; 
use Facebook\GraphUser;
use Facebook\FacebookSDKException;

// grab your app's APP_ID and APP_SECRET from the developer dashboard   
FacebookSession::setDefaultApplication('YOUR_APP_ID', 'YOUR_APP_SECRET');

// create a FacebookSession with the short-lived access token 
$session = new FacebookSession('SHORT-LIVED_ACCESS_TOKEN');

// Get the AccessToken entity. 
$accessToken = $session->getAccessToken();

try { // get a long-lived token from the short-lived one 
    echo $longLivedAccessToken = $accessToken->extend(); 
} catch(FacebookSDKException $e) { 
    echo 'Error extending the short-lived access token: ' . $e->getMessage(); 
    exit; 
}

Copy the long-lived access token.

To create a never-expiring page access token, run this script. It will list all Facebook pages that you administer, with their names, IDs and access tokens:

<?php
define('FACEBOOK_SDK_V4_SRC_DIR', '/PATH/TO/fb/src/Facebook/'); 
require 'fb/autoload.php'; 
use Facebook\FacebookSession; 
use Facebook\GraphUser;
use Facebook\FacebookRequest; 
use Facebook\FacebookRequestException; 

FacebookSession::setDefaultApplication('YOUR_APP_ID', 'YOUR_APP_SECRET');

// create a FacebookSession with the long-lived access token 
$session = new FacebookSession('LONG-LIVED_ACCESS_TOKEN');

try {
    // Get a list of pages with you as admin
    $request = new FacebookRequest($session, 'GET', '/me/accounts?fields=name,access_token');
    $pageList = $request->execute()->getGraphObject()->asArray();
    foreach ($pageList as $page) {
        print_r($page);
    }
} catch (FacebookRequestException $e) {
    echo 'Request error: ' . $e->getMessage();
    exit;
}

Copy the access_token of the proper page. It’s the never-expiring page access token. Also copy the page’s ID, if you didn’t already have it. It’s a long number.

Paste the token into Facebook’s Access Token Debugger to check. ‘Expires’ should say ‘Never’, ‘Valid’ should be ‘True’, and ‘Scopes’ should include ‘manage_pages, publish_pages, public_profile’.

Post to Facebook page

Fairly easy, given we now have the proper token.

<?php
define('FACEBOOK_SDK_V4_SRC_DIR', '/PATH/TO/fb/src/Facebook/'); 
require 'fb/autoload.php'; 

use Facebook\FacebookSession;
use Facebook\FacebookRequest;
// use Facebook\GraphUser; // edit 2015-11-03: not used
use Facebook\FacebookRequestException;

FacebookSession::setDefaultApplication('YOUR_APP_ID', 'YOUR_APP_SECRET');

$neverExpiringToken = 'NEVER-EXPIRING_PAGE_ACCESS_TOKEN';
$pageID = 'PAGE_ID';

// create a FacebookSession with the never-expiring page access token 
$session = new FacebookSession($neverExpiringToken);

try {
    $post_id = (new FacebookRequest(
        $session, 
        'POST', 
        '/' . $pageID . '/feed', 
        array(
                'access_token'  => $neverExpiringToken,
                'message'   => 'boy do I love the Graph API',
                'link'      => 'http://www.contentecontent.com/blog/',
                'picture'   => 'image URL here',
                'name'      => 'name here',
                'description'=> 'description here'
        )
    )
    )->execute()->getGraphObject()->asArray();
} catch (FacebookRequestException $e) {
    echo 'ERROR! ' . __LINE__ . $e->getMessage();   
} catch (Exception $e) {
    echo 'ERROR! ' . __LINE__ . $e->getMessage();
}

$post_id should now contain the ID of the post you just made to the page.

Make the posts visible to the world

While the app is in development mode, which it is by default, the postings are only visible to you. In the app’s dashboard, set the app to Public in the Status & Review tab.