EntityHiddenType

EntityHiddenTransformer.php

<?php

namespace App\Form\DataTransformer;

use Doctrine\ORM\EntityManagerInterface;
use Symfony\Component\Form\DataTransformerInterface;
use Symfony\Component\Form\Exception\TransformationFailedException;

class EntityHiddenTransformer implements DataTransformerInterface
{
    /**
     * @var EntityManagerInterface
     */
    private $entityManager;

    /**
     * @var string
     */
    private $className;

    /**
     * @var string
     */
    private $primaryKey;

    public function __construct(EntityManagerInterface $objectManager, string $className, $primaryKey = "id")
    {
        $this->entityManager = $objectManager;
        $this->className = $className;
        $this->primaryKey = $primaryKey;
    }

    public function getEntityManager(): EntityManagerInterface
    {
        return $this->entityManager;
    }

    /**
     * Transforms an object (entity) to a string (number).
     *
     * @param object|null $entity
     *
     * @return string
     */
    public function transform($entity)
    {
        if (null === $entity) {
            return '';
        }

        $method = 'get' . ucfirst($this->primaryKey);

        // Probably worth throwing an exception if the method doesn't exist
        // Note: you can always use reflection to get the PK even though there's no public getter for it

        return $entity->$method();
    }

    /**
     * Transforms a string (number) to an object (entity).
     *
     * @param string $identifier
     *
     * @return object|null
     * @throws TransformationFailedException if object (entity) is not found.
     */
    public function reverseTransform($identifier)
    {
        if (!$identifier) {
            return null;
        }

        $entity = $this->entityManager->getRepository($this->className)
            ->find($identifier);

        if (null === $entity) {
            // causes a validation error
            // this message is not shown to the user
            // see the invalid_message option
            throw new TransformationFailedException(sprintf(
                'An entity with ID "%s" does not exist!',
                $identifier
            ));
        }

        return $entity;
    }
}

EntityHiddenType.php

<?php


namespace App\Form;


use App\Form\DataTransformer\EntityHiddenTransformer;
use Doctrine\ORM\EntityManagerInterface;
use Symfony\Component\Form\AbstractType;
use Symfony\Component\Form\DataTransformerInterface;
use Symfony\Component\Form\Extension\Core\Type\HiddenType;
use Symfony\Component\Form\FormBuilderInterface;
use Symfony\Component\OptionsResolver\OptionsResolver;

class EntityHiddenType extends AbstractType
{
    /**
     * @var DataTransformerInterface $transformer
     */
    private $entityManager;

    /**
     * Constructor
     *
     * @param DataTransformerInterface $transformer
     */
    public function __construct(EntityManagerInterface $entityManager)
    {
        $this->entityManager = $entityManager;
    }

    /**
     * @inheritDoc
     */
    public function buildForm(FormBuilderInterface $builder, array $options)
    {
        // attach the specified model transformer for this entity list field
        //        // this will convert data between object and string formats
        $builder
            ->addModelTransformer(
                new EntityHiddenTransformer($this->entityManager, $options['class'], $options['primary_key'])
            );
    }

    public function configureOptions(OptionsResolver $resolver)
    {
        $resolver->setDefaults([
            'class' => null,
            'primary_key' => 'id',
        ]);
    }

    /**
     * @inheritDoc
     */
    public function getParent()
    {
        return HiddenType::class;
    }

    /**
     * @inheritDoc
     */
    public function getName()
    {
        return 'entityhidden';
    }
}