How to post on facebook fan page from a website with PHP? - php

Question

I need to post an article right after the user create that on their backend.
I'm using sdk-php with this script:
require 'facebook-php-sdk/src/facebook.php';
$config = array(
'appId' => 'xxxxxxxxxxxxxxxxxxxxxxxx',
'secret' => 'xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx',
'allowSignedRequest' => false
);
$facebook = new Facebook($config);
$params = array(
"access_token" => "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx",
"message" => "Message",
"link" => "http://www.myarticle.com",
"picture" => "http://www.myarticle.com/img1.png",
"name" => "Name",
"caption" => "Caption",
"description" => "Description."
);
// post to Facebook
try {
$result = $facebook->api('/THE_PAGE_ID/feed', 'POST', $params);
echo 'Successfully posted to Facebook';
} catch(Exception $e) {
echo $e->getMessage();
}
This script sometimes works, sometimes not and the Exception is "Error validating access token: This may be because the user logged out or may be due to a system error." and sometimes the post is created as "/me" to The_Page_wall.
Any idea?

Answer 1

I guess you're using a so-called short-lived User Access Token. Get an overview of the different kinds of Access Tokens here:
https://developers.facebook.com/docs/facebook-login/access-tokens/
I think you have two scenarios here:
Exchange you short-lived token via this endpoint to long-lived ones
(60 days):
https://developers.facebook.com/docs/facebook-login/access-tokens/#extending
Use Page Access Tokens if you don't need the Posts to be posted by
an actual User, but the Page itself:
https://developers.facebook.com/docs/facebook-login/access-tokens/#pagetokens