gistfile1.txt

    protected function editAction(Post $post)
    {
        $factory = new HelloFormFactory($this->get('form.factory'));
        $form = $factory->getPostForm($post);

        if ($this->get('request')->getMethod() === 'POST') {
            $form->bindRequest($this->get('request'));

            if ($form->isValid()) {
                $em = $this->get('doctrine.orm.default_entity_manager');
                $em->persist($post);
                $em->flush();

                return new RedirectResponse($this->generateUrl('hello_index'));
            }
        }

        return $this->render('HelloBundle:Hello:edit.html.twig', array(
            'form' => $form->getRenderer(),
        ));
    }