Fatal error: Call to undefined method stdClass::stream_publish() - php

Question

Well I am trying to post on facebook's wall but I get this error:
Fatal error: Call to undefined method stdClass::stream_publish()
The code I am trying is this
<?php
define('FB_APIKEY', '<Your Api Key>');
define('FB_SECRET', '<Secret>');
define('FB_SESSION', '<Session>');
require_once('facebook.php');
echo "post on wall";
echo "<br/>";
try {
$facebook = new Facebook(FB_APIKEY, FB_SECRET);
$facebook->api_client->session_key = FB_SESSION;
$facebook->api_client->expires = 0;
$message = '';
$attachment = array(
'name' => $_POST["name"],
'href' => $_POST["href"],
'description' => $_POST["description"],
'media' => array(array('type' => 'image',
'src' => $_POST["src"],
'href' => $_POST["href"])));
$action_links = array( array('text' => 'Visit Us', 'href' => '<link to some place here>'));
$attachment = json_encode($attachment);
$action_links = json_encode($action_links);
$target_id = "<Target Id>";
$session_key = FB_SESSION;
if( $facebook->api_client->stream_publish($message, $attachment, $action_links, null, $target_id)) {
echo "Added on FB Wall";
}
} catch(Exception $e) {
echo $e . "<br />";
}
?>

Answer 1

Well, as it is written in the error message there is no method "stream_publish" in $facebook->api_client.
Consult the manual of the library you are using to connect to the facebook.

Answer 2

If $facebook->api_client is not an object, then the line:
$facebook->api_client->session_key = FB_SESSION;
Will make php silently cast $facebook->api_client to an object of type stdClass. Which, later on down the code, will cause the Fatal error: Call to undefined method stdClass::stream_publish() that you are getting.
Try changing:
...
$facebook = new Facebook(FB_APIKEY, FB_SECRET);
$facebook->api_client->session_key = FB_SESSION;
$facebook->api_client->expires = 0;
...
to catch for when api_client is false (or, perhaps, not an object):
...
$facebook = new Facebook(FB_APIKEY, FB_SECRET);
if (!( $facebook->api_client )) {
//throw error
echo 'Need to sort this bit out';
exit;
}
$facebook->api_client->session_key = FB_SESSION;
$facebook->api_client->expires = 0;
...
And then, if that does throw an error, you'd need to investigate why $facebook->api_client is null.