Symfony2 Form Entity Update - forms

Question

Can anyone please show me a specific example of a Symfony2 form entity update? The book only shows how to create a new entity. I need an example of how to update an existing entity where I initially pass the id of the entity on the query string.
I'm having trouble understanding how to access the form again in the code that checks for a post without re-creating the form.
And if I do recreate the form, it means I have to also query for the entity again, which doesn't seem to make much sense.
Here is what I currently have but it doesn't work because it overwrites the entity when the form gets posted.
public function updateAction($id)
{
$em = $this->getDoctrine()->getEntityManager();
$testimonial = $em->getRepository('MyBundle:Testimonial')->find($id);
$form = $this->createForm(new TestimonialType(), $testimonial);
$request = $this->get('request');
if ($request->getMethod() == 'POST') {
$form->bindRequest($request);
echo $testimonial->getName();
if ($form->isValid()) {
// perform some action, such as save the object to the database
//$testimonial = $form->getData();
echo 'testimonial: ';
echo var_dump($testimonial);
$em->persist($testimonial);
$em->flush();
return $this->redirect($this->generateUrl('MyBundle_list_testimonials'));
}
}
return $this->render('MyBundle:Testimonial:update.html.twig', array(
'form' => $form->createView()
));
}

Answer 1

Working now. Had to tweak a few things:
public function updateAction($id)
{
$request = $this->get('request');
if (is_null($id)) {
$postData = $request->get('testimonial');
$id = $postData['id'];
}
$em = $this->getDoctrine()->getEntityManager();
$testimonial = $em->getRepository('MyBundle:Testimonial')->find($id);
$form = $this->createForm(new TestimonialType(), $testimonial);
if ($request->getMethod() == 'POST') {
$form->bindRequest($request);
if ($form->isValid()) {
// perform some action, such as save the object to the database
$em->flush();
return $this->redirect($this->generateUrl('MyBundle_list_testimonials'));
}
}
return $this->render('MyBundle:Testimonial:update.html.twig', array(
'form' => $form->createView()
));
}

Answer 2

This is actually a native function of Symfony 2 :
You can generate automatically a CRUD controller from the command line (via doctrine:generate:crud) and the reuse the generated code.
Documentation here :
http://symfony.com/doc/current/bundles/SensioGeneratorBundle/commands/generate_doctrine_crud.html

Answer 3

A quick look at the auto-generated CRUD code by the Symfony's command generate:doctrine:crudshows the following source code for the edit action
/**
* Displays a form to edit an existing product entity.
*
* #Route("/{id}/edit", name="product_edit")
* #Method({"GET", "POST"})
*/
public function editAction(Request $request, Product $product)
{
$editForm = $this->createForm('AppBundle\Form\ProductType', $product);
$editForm->handleRequest($request);
if ($editForm->isSubmitted() && $editForm->isValid()) {
$this->getDoctrine()->getManager()->flush();
return $this->redirectToRoute('product_edit', array('id' => $product->getId()));
}
return $this->render('product/edit.html.twig', array(
'product' => $product,
'edit_form' => $editForm->createView(),
));
}
Note that a Doctrine entity is passed to the action instead of an id (string or integer). This will make an implicit parameter conversion and saves you from manually fetching the corresponding entity with the given id.
It is mentioned as best practice in the Symfony's documentation