Symfony2 collection of Entities - how to add/remove association with existing entities?

Question

1. Quick overview

1.1 Goal

What I\'m trying to achieve is a create/edit user tool. Editable fields are:

• username (type: text)
• plai

Answer 1

I've come to the same conclusion that there's something wrong with the Form component and can't see an easy way to fix it. However, I've come up with a slightly less cumbersome workaround solution that is completely generic; it doesn't have any hard-coded knowledge of entities/attributes so will fix any collection it comes across:

Simpler, generic workaround method

This doesn't require you to make any changes to your entity.

use Doctrine\Common\Collections\Collection;
use Symfony\Component\Form\Form;

# In your controller. Or possibly defined within a service if used in many controllers

/**
 * Ensure that any removed items collections actually get removed
 *
 * @param \Symfony\Component\Form\Form $form
 */
protected function cleanupCollections(Form $form)
{
    $children = $form->getChildren();

    foreach ($children as $childForm) {
        $data = $childForm->getData();
        if ($data instanceof Collection) {

            // Get the child form objects and compare the data of each child against the object's current collection
            $proxies = $childForm->getChildren();
            foreach ($proxies as $proxy) {
                $entity = $proxy->getData();
                if (!$data->contains($entity)) {

                    // Entity has been removed from the collection
                    // DELETE THE ENTITY HERE

                    // e.g. doctrine:
                    // $em = $this->getDoctrine()->getEntityManager();
                    // $em->remove($entity);

                }
            }
        }
    }
}

Call the new cleanupCollections() method before persisting

# in your controller action...

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

        // 'Clean' all collections within the form before persisting
        $this->cleanupCollections($form);

        $em->persist($user);
        $em->flush();

        // further actions. return response...
    }
}