symfony deserialize EntityNormalizer -- объект по id. Сохранение связаннной сущности

Можно создать App\Normalizer\EntityNormalizer.php с таким содержимым:

<?php declare(strict_types = 1);

namespace App\Normalizer;

use Doctrine\ORM\EntityManagerInterface;
use Symfony\Component\Serializer\Normalizer\ObjectNormalizer;
use Symfony\Component\Serializer\Mapping\Factory\ClassMetadataFactoryInterface;
use Symfony\Component\Serializer\NameConverter\NameConverterInterface;
use Symfony\Component\PropertyAccess\PropertyAccessorInterface;
use Symfony\Component\PropertyInfo\PropertyTypeExtractorInterface;
/**
 * Entity normalizer
 */
class EntityNormalizer extends ObjectNormalizer
{
    /**
     * Entity manager
     * @var EntityManagerInterface
     */
    protected $em;
    /**
     * Entity normalizer
     * @param EntityManagerInterface $em
     * @param ClassMetadataFactoryInterface|null $classMetadataFactory
     * @param NameConverterInterface|null $nameConverter
     * @param PropertyAccessorInterface|null $propertyAccessor
     * @param PropertyTypeExtractorInterface|null $propertyTypeExtractor
     */
    public function __construct(
        EntityManagerInterface $em,
        ?ClassMetadataFactoryInterface $classMetadataFactory = null,
        ?NameConverterInterface $nameConverter = null,
        ?PropertyAccessorInterface $propertyAccessor = null,
        ?PropertyTypeExtractorInterface $propertyTypeExtractor = null
    ) {
        parent::__construct($classMetadataFactory, $nameConverter, $propertyAccessor, $propertyTypeExtractor);
        // Entity manager
        $this->em = $em;
    }
    /**
     * @inheritDoc
     */
    public function supportsDenormalization($data, $type, $format = null)
    {
        return strpos($type, 'App\\Entity\\') === 0 && (is_numeric($data) || is_string($data));
    }
    /**
     * @inheritDoc
     */
    public function denormalize($data, $class, $format = null, array $context = [])
    {
        return $this->em->find($class, $data);
    }
}

О подключении вместе с DateTimeNormilizer см. тут, или просто в оригинальной статье-источнике https://medium.com/cloudstek/using-the-s...