This extracts the user IDs that were sent an fb app request using the JavaScript Facebook API

get_fb_user_ids_from_request.php

//This code is depricated, with the release of the PHP GRAPH LIB v4.0, still the API calls for getting userIDs is very similar.

//This parses the data generated in this piece of code https://gist.github.com/nicholasdunbar/8809354
public function getUserIDsFromRequests($sentRequestsStr){
            $config = Zend_Registry::get ( 'config' );
            $sentRequestsArray = explode(",", $sentRequestsStr);
            $sentRequestsLen = count ( $sentRequestsArray );
            $sentUsersStr = "";
            if ($config->isFacebookApp){
                $facebook = new Facebook(array(
                                  'appId'  => $config->appID,
                                  'secret' => $config->appSecretKey,
                                  'cookie' => true
                                ));
                for ($i = 0; $i < $sentRequestsLen; $i++){
                    $cmd = "/".$sentRequestsArray[$i]."/";
                    //echo $cmd."\n";
                    try{
                        $result = $facebook->api($cmd);
                        //echo "success\n";
                        if ($result['to']['id']){
                            $sentUsersStr .= $result['to']['id'];
                            if ($i < $sentRequestsLen-1){
                                $sentUsersStr .= ",";
                            }
                        }

                        //print_r($result);
                        //exit();
                        //echo "\n";

                    } catch (FacebookApiException $e) {
                        //$this->_logger->log ( $result, Zend_Log::INFO );
                        //print_r($e);
                    }
                }
                return $sentUsersStr;
            }
        }
        
//To better understand how to use this code check out the following blog article:
//http://www.actionscript-flash-guru.com/blog/43-list-of-user-ids-from-requests-dialog-migrating-from-fbrequest-form-to-fbui-apprequests-facebook-api-javascript-php-.php