chill-bundles/src/Bundle/ChillMainBundle/Serializer/Normalizer/DoctrineExistingEntityNormalizer.php

<?php

namespace Chill\MainBundle\Serializer\Normalizer;

use Symfony\Component\Serializer\Normalizer\DenormalizerInterface;
use Doctrine\ORM\EntityManagerInterface;
use Symfony\Component\Serializer\Normalizer\AbstractNormalizer;
use Doctrine\ORM\Mapping\ClassMetadata;
use Symfony\Component\Serializer\Mapping\Factory\ClassMetadataFactoryInterface;
use Symfony\Component\Serializer\Mapping\ClassMetadataInterface as SerializerMetadata;


class DoctrineExistingEntityNormalizer implements DenormalizerInterface
{
    private EntityManagerInterface $em;

    private ClassMetadataFactoryInterface $serializerMetadataFactory;


    public function __construct(EntityManagerInterface $em, ClassMetadataFactoryInterface $serializerMetadataFactory)
    {
        $this->em = $em;
        $this->serializerMetadataFactory = $serializerMetadataFactory;
    }

    public function denormalize($data, string $type, string $format = null, array $context = [])
    {
        if (\array_key_exists(AbstractNormalizer::OBJECT_TO_POPULATE, $context)) {
            return $context[AbstractNormalizer::OBJECT_TO_POPULATE];
        }

        return $this->em->getRepository($type)
            ->find($data['id']);
    }

    public function supportsDenormalization($data, string $type, string $format = null)
    {
        if (FALSE === \is_array($data)) {
            return false;
        }

        if (FALSE === \array_key_exists('id', $data)) {
            return false;
        } 

        if (FALSE === $this->em->getClassMetadata($type) instanceof ClassMetadata) {
            return false; 
        }

        // does have serializer metadata, and class discriminator ?
        if ($this->serializerMetadataFactory->hasMetadataFor($type)) {

            $classDiscriminator = $this->serializerMetadataFactory
                ->getMetadataFor($type)->getClassDiscriminatorMapping();

            if ($classDiscriminator) {
                $typeProperty = $classDiscriminator->getTypeProperty();

                // check that only 2 keys
                // that the second key is property
                // and that the type match the class for given type property 
                return count($data) === 2
                    && \array_key_exists($typeProperty, $data) 
                    && $type === $classDiscriminator->getClassForType($data[$typeProperty]);
            }
        }

        // we do not have any class discriminator. Check that the id is the only one key
        return count($data) === 1;
    }
}