gistfile1.php

	function get_facebook_cookie() {
            $app_id             = $this->config->item('facebook_api_key');
            $application_secret = $this->config->item('facebook_secret_key');

            if(isset($_COOKIE['fbs_' . $app_id])){
                    $args = array();
                    parse_str(trim($_COOKIE['fbs_' . $app_id], '\\"'), $args);
                    ksort($args);
                    $payload = '';
                    foreach ($args as $key => $value) {
                            if ($key != 'sig') {
                            $payload .= $key . '=' . $value;
                            }
                    }
                    if (md5($payload . $application_secret) != $args['sig']) {
                            return null;
                    }
                    return $args;
            }
            else{
                    return null;
            }
    }