Update object using REST API in Symfony2 with FOSRestBundle

Question

I want to update an entity with Doctrine2. I use a form to create and update entities. I want to send an object as parameters for my REST URL.

My code is like this :

public function putUpdateAction(Client $obj){
    $em = $this->getDoctrine()->getEntityManager();
    $serv = $this->getDoctrine()->getRepository("AccessRhBundle:Client")
                 ->findOneBy(array('id' => obj->getId));
    $serv->setNom($obj->getNom());
    $em->merge($obj);
    $em->flush();
}

#app/config/routing.yml

rest:
  type : rest
  resource : clientBundle\Controller\ClientController
  prefix : /rest

When I call this method from my client application I get error 404 URL not found.

I try to see the debugger and the result was that url contain No route found for "PUT /api/updateClient/[object%20Object]": Method Not Allowed (Allow: GET, HEAD) which is not defined.

Someone have an idea how I can send an object as parameters of a rest method in symfony?