Hidden field for Symfony2 entities

EntityHiddenType.php

<?php

namespace Dpn\ToolsBundle\Form\Type;

use Symfony\Component\Form\AbstractType;
use Dpn\ToolsBundle\Form\DataTransformer\EntityToIdTransformer;
use Symfony\Component\Form\FormBuilderInterface;
use Symfony\Component\OptionsResolver\OptionsResolverInterface;
use Doctrine\Common\Persistence\ObjectManager;

class EntityHiddenType extends AbstractType
{
    /**
     * @var ObjectManager
     */
    protected $objectManager;

    public function __construct(ObjectManager $objectManager)
    {
        $this->objectManager = $objectManager;
    }

    public function buildForm(FormBuilderInterface $builder, array $options)
    {
        $transformer = new EntityToIdTransformer($this->objectManager, $options['class']);
        $builder->addModelTransformer($transformer);
    }

    public function setDefaultOptions(OptionsResolverInterface $resolver)
    {
        $resolver
            ->setRequired(array('class'))
            ->setDefaults(array(
                'invalid_message' => 'The entity does not exist.',
            ))
        ;
    }

    public function getParent()
    {
        return 'hidden';
    }

    public function getName()
    {
        return 'entity_hidden';
    }
}

EntityToIdTransformer.php

<?php

namespace Dpn\ToolsBundle\Form\DataTransformer;

use Symfony\Component\Form\DataTransformerInterface;
use Symfony\Component\Form\Exception\TransformationFailedException;
use Doctrine\Common\Persistence\ObjectManager;

class EntityToIdTransformer implements DataTransformerInterface
{
    /**
     * @var ObjectManager
     */
    protected $objectManager;

    /**
     * @var string
     */
    protected $class;

    public function __construct(ObjectManager $objectManager, $class)
    {
        $this->objectManager = $objectManager;
        $this->class = $class;
    }

    public function transform($entity)
    {
        if (null === $entity) {
            return;
        }

        return $entity->getId();
    }

    public function reverseTransform($id)
    {
        if (!$id) {
            return null;
        }

        $entity = $this->objectManager
                       ->getRepository($this->class)
                       ->find($id);

        if (null === $entity) {
            throw new TransformationFailedException();
        }

        return $entity;
    }
}

Great job!
One question, how do I pass the class?

Worked like a charm! Thanks!

Remember add the service in the bundle services.yml to allow use the new field type

services:
 acme_demo.type.entity_hidden:
   class: Acme\DemoBundle\Form\Type\EntityHiddenType
   arguments: ["@doctrine.orm.entity_manager"]
   tags:
   - { name: form.type, alias: entity_hidden }

add the services.yml to the config.yml imports:

 imports:
  - { resource: "@AcmeDemoBundle/Resources/config/services.yml" }

Modify the namespaces to fit with your bundle structure

and just add a new "entity_hidden" field to the form in this way:

    $builder
            ->add('email')
            ->add('name')
            ->add('car', 'entity_hidden', array(
                'class' => 'Acme\DemoBundle\Entity\Car'
            ))

More info about apply the DataTransformer in the symfony2 Docs:

http://symfony.com/doc/current/cookbook/form/data_transformers.html#creating-the-transformer

It worked!, thanks @dreipunktnull

It worked for me as well, thanks.

I found this very useful - thanks!

Thanks for sharing this, it helped a lot!

Thanks! very useful...

Thanks, is fine!

Do you guess this works the same if I only change the argument for ODM? Meaning, changing this in the configuration of the service: arguments: ["@doctrine.odm.mongodb.document_manager"]

Excuse my questions, im new to symfony. How can i pass some options to the form since i used this in controller?

private function createEditForm(Sms $entity)
{
        $form = $this->createForm(new SmsType(), $entity, array(
            'action' => $this->generateUrl('sms_update', array('id' => $entity->getId())),
            'method' => 'PUT',
        ));

        $form->add('submit', 'submit', array('label' => 'Update'));

        return $form;
 }

Wow, I didn't notice all those comments. Thanks and sorry for not answering some of them.

@alfchee: yes, that should work as well.
@mdjaman: what kind of options do you mean?

Thx 4 answering. I need to pass user entity

Thx found what i was looking for. Thought that only instance of AbstractType could be passed in

$this->createForm('acme_userbundle_sms', $entity, array(
            'action' => $this->generateUrl('sms_create'),
            'method' => 'POST',
        ));
```php
form_name 'acme_userbundle_sms' could be passed. Thks for your time

Thanks, dude =)

• 1 cheers !

Thanks!!! Great Job!!!

If the user doesn't write the class option:

$builder
        ->add('car', 'hidden_entity', array())
;

the class is null and the transformation throws the next error:
Class '' does not exist

If the user uses the method setRequired() in EntityHiddenType file:

public function setDefaultOptions(OptionsResolverInterface $resolver)
{
    $resolver
        ->setRequired(array('class'))
        ->setDefaults(array(
            'invalid_message' => 'The entity does not exist.',
        ))
    ;
}

the application throws a 500 error with the next information:
The required option "class" is missing.

Hi @jamogon,

thanks for the hint. I updated the Gist accordingly. Didn't even know about the setRequired() method of the OptionsResolver.

Cheers
Björn

Great Job !!

Thank you !

Why Symfony community would not integrate this solution. it's very useful !

👍

Did you ever propose this improvement to Symfony, @bjo3rnf ?

There also seems to be a simple workaround using the property_path:

$builder->add('entity', 'hidden', array('property_path' => 'entity.id'));

as mentioned by @webmozart here:
symfony/symfony#3182

And it looks like it is finally going to make it into symfony here:
symfony/symfony#8293

Thank you! Works great!

How to pass default value to Hidden_entity field? for eg. I have test controller which has field Author. Author I am getting from db after user logs in to system.

How can I set an entity in a onPreSubmit or preSetData and have it attach to the form entity?

Thanks! It helped a lot!

I forked it to make it compatible with symfony 2.8 ( https://gist.github.com/xanou/e630e4e25df60d33b050 )

Thanks, you made my day!