Full flow - four page example (easier to edit and understand for an example)
So the config just has the basic app info...
When you load index.php - it redirects to facebook to get authorization for the page.. (probably already have this.. but covering all bases)
Facebook then redirects back to the redirecturl (backfromfb.php)...
Facebook returns the access token as a hash and not a get variable, so this page refreshes with the hash as a variable...
It then loads the PageUpdate.php which handles looping through the app/admin tokens and finds the correct one for the page you want to post to..
Then it builds the post and submits it..
It sounds like you have an understanding of most of this... So hopefully this will help you with that last bit.
config.php
<?php
$config = array(
'appId' => 'YOUR APP ID',
'secret' => 'YOUR APP SECRET',
'cookie' => true;
);
$baseurl = 'http://yoursite.com/';
$returnpage = 'backfromfb.php';
require_once('library/facebook.php');
?>
index.php
<?php require_once('config.php'); ?>
<html><head><title>Redirecting for auth</title></head><body><script type="text/javascript">
window.location.href = 'https://www.facebook.com/dialog/oauth?client_id=<?php echo $config['appId']; ?>&redirect_uri=<?php echo $baseurl . $returnpage; ?>&scope=manage_pages&response_type=token';
</script></body></html>
backfromfb.php
<?php
require_once('config.php');
// this page just passes the access token from the hash to a GET arg...
if (!isset($_GET['access_token'])) {
?>
<html><head><title>Redirecting</title></head><body><script type="text/javascript">
accessToken = window.location.hash.substring(1);
window.location.href = '<?php echo $baseurl . $returnpage; ?>?' + accessToken;
</script></body></html>
<?php
} else {
require_once('PageUpdate.php');
} ?>
PageUpdate.php
<?php
require_once('config.php');
$pageID = "123456 WHatever you page id is";
$AppToken = array(
'access_token' => $_REQUEST['acess_token']
);
$fb = new Facebook($config);
// Load APP page access rights for user via AppToken
$pageAdmin = $fb->api('/me/accounts', 'GET', $AppToken);
// Find the page access token
foreach ($pageAdmin['data'] as $data) {
if ($data['id'] == $pageID) {
$pageToken['access_token'] = $data['access_token'];
continue;
}
}
// compile the post
$WallPost = array(
'message' => 'Test post from my app!'
); // you can also use 'picture', 'link', 'name', 'caption', 'description', 'source'....
//http://developers.facebook.com/docs/reference/api/
// post to wall
$response = $fb->api($pageID . '/feed','POST',$WallPost);
if($response) {
echo 'Success!';
echo '<pre>' . $response . '</pre>';
} else echo "failed";
?>
Best Answer
Your app may not have permission to post on the given friend's wall.
When a user authorizes your app, they give you permissions to act on their behalf.
This permission does not ensure that you can always post on friends' walls, just as the user may not be able to post on the wall using the UI.