title: Symfony: passing object to controller method
body: <p>I'm following this guide in order to create a RESTFUL api:
  <a href="http://williamdurand.fr/2012/08/02/rest-apis-with-symfony2-the-right-way/" rel="nofollow">http://williamdurand.fr/2012/08/02/rest-apis-with-symfony2-the-right-way/</a></p>
  
  <p>In POST section, it uses object User as input of its edit method. I'm trying to do the same with my controller class, but I'm getting the following error:</p>
  
  <blockquote>
    <p>Unable to guess how to get a Doctrine instance from the request
    information</p>
  </blockquote>
  
  <p>Can somebody help me?
  Thank you</p>
  
  <p><strong>Update:</strong></p>
  
  <p>Now the definition of the method looks like this:</p>
  
  <pre><code>  /**
     * @Route("/rest/categories/{id}")
     * @ParamConverter("category", class="TouristAppCoreBundle:Category")
     * @Template()
     */
    public function rest_editAction(Category $category)
  </code></pre>