cannot access to Json with restler library

Question

I create an rest api with php usring restler libary, its work well in my PC but when I uploaded the api to server, problems begin.. this function in my api

<?php
class user {
/**
        @url GET /
*/
    public function getAllInfo(){
        $link = new PDO('mysql:host=localhost;dbname=---;charset=utf8','---','-----');
        $handle = $link->prepare('select * from user');
        $handle->execute();
        $result = $handle->fetchAll(PDO::FETCH_OBJ);

        if(empty($result)){
            $err = new stdClass();
            $err->error = "No user found";
            return $err;
        }
        else{
            return $result;
        }
}

require_once 'restler.php';

$r = new Restler(); 
$r->setSupportedFormats('JsonFormat'); 
$r->addAPIClass('user'); 
$r->handle();
?>

when I access to this page nothing appear in browser I thought the problem is this page can't access to require_once 'restler.php'; but I was wrong, because whan I print $r->handle(); like this print_r($r->handle()); this is what I see in browser

Luracast\Restler\EventDispatcher Object ( [listeners:Luracast\Restler\EventDispatcher:private] => Array ( ) [events:protected] => Array ( ) )

I don't know what is that or what I should do to print my json, my database is full of data, its return json if my query doesn't have restler, but I need use restler with my code