How to post to friends wall automatically using Facebook PHP SDK - php

Question

Is it possible to post to a friends wall/timeline in facebook using an app even if the user is not currently logged in? Here's the code that I'm currently working on, as you can see it posts a message on a friends wall(substitute the friend_id with an actual profile id). This works but a user has to logged in in order to perform this operation.
I don't have any idea what to do if I want this script to execute automatically(without user intervention).
<?php
require 'php_sdk/src/facebook.php';
$facebook = new Facebook(array(
'appId' => 'XXX',
'secret' => 'XXX',
));
$session = $facebook->getUser();
$me = null;
if($session){
try{
$me = $facebook->api('/me');
$facebook->api('/friend_id/feed', 'post', array('message'=>'hello without user!'));
}catch(FacebookApiException $e){
echo $e->getMessage();
}
}
if($me){
$logoutUrl = $facebook->getLogoutUrl();
echo "<a href='$logoutUrl'>Logout</a>";
}else{
$loginUrl = $facebook->getLoginUrl(array(
'scope' => 'user_about_me,user_birthday,user_location,email,read_friendlists,friends_location,friends_birthday,publish_stream'
));
echo "<a href='$loginUrl'>Login</a>";
}
?>
Any ideas? Code samples, and links to specific documents that can help me gain a bit of idea on how this works is greatly appreciated thanks!

Answer 1

When the user is logged in, you need to trap their "Access Token"
$facebook = new Facebook(array(
'appId' => 'XXX',
'secret' => 'XXX',
));
// NOTE: wrap these in try/catch blocks for safety - this is example only
$session = $facebook->getUser();
$access_token = $facebook->getAccessToken();
To post as them later, you use the access token
$facebook = new Facebook(array(
'appId' => 'XXX',
'secret' => 'XXX',
));
// NOTE: wrap these in try/catch blocks for safety - this is example only
$facebook->setAccessToken($access_token);
// Then check /me and you should still have the same user.
// Then post to /me/feed to post to the wall.
The token will be valid for 2 days. You can extend this to 60 days if you want.
Edit: For exenteding the token, you call the function
$facebook->setExtendedAccessToken();
immediately before "getAccessToken" call.