Entity translations implementation suggestion with Symfony 7.x & Doctrine 3 & EasyAdmin

Category.php

<?php

//
// Example of implementation of an entity translatable
//

declare(strict_types=1);

namespace App\Entity;

use App\Tooling\Translation\Model\TranslatableInterface;
use App\Tooling\Translation\Model\TranslatableTrait;
use Doctrine\Common\Collections\ArrayCollection;
use Doctrine\Common\Collections\Collection;
use Doctrine\ORM\Mapping as ORM;
use Symfony\Component\Uid\Uuid;

/** @implements TranslatableInterface<CategoryTranslation> */
#[ORM\Entity()]
class Category implements TranslatableInterface
{
    /** @use TranslatableTrait<CategoryTranslation> */
    use TranslatableTrait;

    #[ORM\Id]
    #[ORM\Column]
    private string $id;

    public function __construct()
    {
        $this->id = Uuid::v4()->toRfc4122();
    }

    public function getId(): string
    {
        return $this->id;
    }

    public function getName(): string
    {
        return $this->getAnyTranslation()->getName();
    }
}

CategoryCrudController.php

<?php

//
// Example of usage within easyadmin
//

declare(strict_types=1);

namespace App\Controller\Admin;

use App\Form\CategoryTranslationType;
use App\Entity\Category;
use App\Tooling\Translation\Admin\TranslationsField;
use EasyCorp\Bundle\EasyAdminBundle\Controller\AbstractCrudController;
use EasyCorp\Bundle\EasyAdminBundle\Field\AssociationField;
use EasyCorp\Bundle\EasyAdminBundle\Field\TextField;

class CategoryCrudController extends AbstractCrudController
{
    public static function getEntityFqcn(): string
    {
        return Category::class;
    }

    public function configureFields(string $pageName): iterable
    {
        yield TextField::new('name')->hideOnForm();
        yield TranslationsField::new('translations')
            ->setFormTypeOption('entry_type', CategoryTranslationType::class)
        ;
    }
}

CategoryTranslation.php

<?php

//
// Example of implementation of an entity translation
//

declare(strict_types=1);

namespace App\Entity;

use App\Tooling\Translation\Model\TranslationInterface;
use App\Tooling\Translation\Model\TranslationTrait;
use Doctrine\ORM\Mapping as ORM;
use Symfony\Component\Uid\Uuid;

/** @implements TranslationInterface<Category> */
#[ORM\Entity]
class CategoryTranslation implements TranslationInterface
{
    /** @use TranslationTrait<Category> */
    use TranslationTrait;

    #[ORM\Id]
    #[ORM\Column]
    private string $id;

    #[ORM\Column]
    private ?string $name = null;

    public function __construct()
    {
        $this->id = Uuid::v4()->toRfc4122();
    }

    public function getId(): string
    {
        return $this->id;
    }

    public function getName(): ?string
    {
        return $this->name;
    }

    public function setName(string $name): void
    {
        $this->name = $name;

        $this->generateHierarchy();
    }
}

CategoryTranslationType.php

<?php

//
// Example of usage in a form designed for easyadmin
//

declare(strict_types=1);

namespace App\Form\Admin;

use App\Entity\CategoryTranslation;
use Symfony\Component\Form\AbstractType;
use Symfony\Component\Form\FormBuilderInterface;
use Symfony\Component\OptionsResolver\OptionsResolver;

class CategoryTranslationType extends AbstractType
{
    public function buildForm(FormBuilderInterface $builder, array $options): void
    {
        $builder->add('name');
    }

    public function configureOptions(OptionsResolver $resolver): void
    {
        $resolver->setDefault('data_class', CategoryTranslation::class);
    }
}

TranslatableInterface.php

<?php

declare(strict_types=1);

namespace App\Tooling\Translation\Model;

use Doctrine\Common\Collections\Collection;

/**
 * @template T of TranslationInterface
 */
interface TranslatableInterface
{
    /**
     * @return class-string<T>
     */
    public static function getTranslationEntityClass(): string;

    public function setCurrentLocale(string $locale): void;

    /**
     * @return Collection<string, T>
     */
    public function getTranslations(): Collection;

    /**
     * @return T
     */
    public function getTranslation(?string $locale = null): TranslationInterface;

    /**
     * @return T
     */
    public function getAnyTranslation(): TranslationInterface;
}

TranslatableListener.php

<?php

declare(strict_types=1);

namespace App\Tooling\Translation\EventListener;

use App\Tooling\Translation\LocaleProvider;
use App\Tooling\Translation\Model\TranslatableInterface;
use App\Tooling\Translation\Model\TranslationInterface;
use Doctrine\Bundle\DoctrineBundle\Attribute\AsDoctrineListener;
use Doctrine\Common\EventSubscriber;
use Doctrine\ORM\Event\LoadClassMetadataEventArgs;
use Doctrine\ORM\Event\PostLoadEventArgs;
use Doctrine\ORM\Events;
use Doctrine\ORM\Mapping\ClassMetadata;

/**
 * This class is heavily inspired by the Sylius ORMTranslatableListener.
 *
 * @template Translatable of TranslatableInterface
 * @template Translation of TranslationInterface
 */
#[AsDoctrineListener(event: Events::loadClassMetadata, connection: 'default')]
#[AsDoctrineListener(event: Events::postLoad, connection: 'default')]
class TranslatableListener implements EventSubscriber
{
    public function __construct(private LocaleProvider $localeProvider)
    {
    }

    public function getSubscribedEvents(): array
    {
        return [
            Events::loadClassMetadata,
            Events::postLoad,
        ];
    }

    /**
     * Add mapping to translatable entities.
     */
    public function loadClassMetadata(LoadClassMetadataEventArgs $eventArgs): void
    {
        $classMetadata = $eventArgs->getClassMetadata();
        $reflection = $classMetadata->getReflectionClass();

        if ($reflection->isAbstract()) {
            return;
        }

        if ($reflection->implementsInterface(TranslatableInterface::class)) {
            $this->mapTranslatable($classMetadata);
        }

        if ($reflection->implementsInterface(TranslationInterface::class)) {
            $this->mapTranslation($classMetadata);
        }
    }

    /**
     * Add mapping data to a translatable entity.
     *
     * @param ClassMetadata<Translatable> $metadata
     */
    private function mapTranslatable(ClassMetadata $metadata): void
    {
        /** @var class-string<Translatable> $className */
        $className = $metadata->name;

        if (!$metadata->hasAssociation('translations')) {
            $metadata->mapOneToMany([
                'fieldName' => 'translations',
                'targetEntity' => $className::getTranslationEntityClass(),
                'mappedBy' => 'translatable',
                'fetch' => ClassMetadata::FETCH_EAGER,
                'indexBy' => 'locale',
                'cascade' => ['persist', 'remove', 'detach', 'refresh'],
                'orphanRemoval' => true,
            ]);
        }
    }

    /**
     * Add mapping data to a translation entity.
     *
     * @param ClassMetadata<Translation> $metadata
     */
    private function mapTranslation(ClassMetadata $metadata): void
    {
        /** @var class-string<Translation> $className */
        $className = $metadata->name;

        if (!$metadata->hasAssociation('translatable')) {
            $metadata->mapManyToOne([
                'fieldName' => 'translatable',
                'targetEntity' => $className::getTranslatableEntityClass(),
                'inversedBy' => 'translations',
                'fetch' => ClassMetadata::FETCH_EAGER,
                'joinColumns' => [[
                    'name' => 'translatable_id',
                    'referencedColumnName' => 'id',
                    'onDelete' => 'CASCADE',
                    'nullable' => false,
                ]],
            ]);
        }

        if (!$metadata->hasField('locale')) {
            $metadata->mapField([
                'fieldName' => 'locale',
                'type' => 'string',
                'nullable' => false,
            ]);
        }

        // Map unique index.
        $columns = [
            $metadata->getSingleAssociationJoinColumnName('translatable'),
            'locale',
        ];

        if (!$this->hasUniqueConstraint($metadata, $columns)) {
            $constraints = $metadata->table['uniqueConstraints'] ?? [];

            $constraints[$metadata->getTableName() . '_uniq_trans'] = [
                'columns' => $columns,
            ];

            $metadata->setPrimaryTable([
                'uniqueConstraints' => $constraints,
            ]);
        }
    }

    /**
     * Check if a unique constraint has been defined.
     *
     * @param ClassMetadata<Translation> $metadata
     * @param array<int,string>          $columns
     */
    private function hasUniqueConstraint(ClassMetadata $metadata, array $columns): bool
    {
        if (!isset($metadata->table['uniqueConstraints'])) {
            return false;
        }

        foreach ($metadata->table['uniqueConstraints'] as $constraint) {
            if (!array_diff($constraint['columns'], $columns)) {
                return true;
            }
        }

        return false;
    }

    public function postLoad(PostLoadEventArgs $args): void
    {
        $entity = $args->getObject();

        if (!$entity instanceof TranslatableInterface) {
            return;
        }

        $entity->setCurrentLocale($this->localeProvider->provideCurrentLocale());
    }
}

TranslatableTrait.php

<?php

declare(strict_types=1);

namespace App\Tooling\Translation\Model;

use App\Tooling\Exception\NoTranslationFoundException;
use Doctrine\Common\Collections\ArrayCollection;
use Doctrine\Common\Collections\Collection;
use Symfony\Component\Serializer\Annotation\Groups;

/**
 * @template T of TranslationInterface
 */
trait TranslatableTrait
{
    /**
     * @var Collection<string, T>
     */
    #[Groups(['list-products'])]
    private ?Collection $translations = null;

    private ?string $currentLocale = null;

    public function getTranslations(): Collection
    {
        return $this->translations ?? $this->translations = new ArrayCollection();
    }

    public function getAnyTranslation(): TranslationInterface
    {
        try {
            return $this->getTranslation();
        } catch (NoTranslationFoundException $e) {
        }

        if (0 === $this->translations->count()) {
            throw new NoTranslationFoundException('No translation found for translatable entity.');
        }

        return $this->getTranslations()->first();
    }

    /**
     * @return T
     */
    public function getTranslation(?string $locale = null): TranslationInterface
    {
        if (null === $this->currentLocale && null === $locale) {
            throw new NoTranslationFoundException('No locale has been set and current locale is undefined. See TranslatableListener::postLoad().');
        }

        if (null === $locale) {
            $locale = $this->currentLocale;
        } elseif (null === $this->currentLocale) {
            $this->currentLocale = $locale;
        }

        if ($this->getTranslations()->containsKey($locale)) {
            return $this->getTranslations()->get($locale);
        }

        $translationClass = self::getTranslationEntityClass();
        $translation = new $translationClass();
        $translation->setLocale($locale);
        $translation->setTranslatable($this);

        $this->getTranslations()->set($locale, $translation);

        return $translation;
    }

    public function setCurrentLocale(string $currentLocale): void
    {
        $this->currentLocale = $currentLocale;
    }

    /**
     * @param T $translation
     */
    public function addTranslation(TranslationInterface $translation): void
    {
        $this->getTranslations()->add($translation);
    }

    /**
     * @param T $translation
     */
    public function removeTranslation(TranslationInterface $translation): void
    {
        $this->getTranslations()->removeElement($translation);
    }

    public static function getTranslationEntityClass(): string
    {
        return static::class . 'Translation';
    }
}

TranslationInterface.php

<?php

declare(strict_types=1);

namespace App\Tooling\Translation\Model;

/**
 * @template T of TranslatableInterface
 */
interface TranslationInterface
{
    /**
     * @return class-string<T>
     */
    public static function getTranslatableEntityClass(): string;

    public function getLocale(): string;

    public function setLocale(string $locale): void;

    /**
     * @param T $translatable
     */
    public function setTranslatable(TranslatableInterface $translatable): void;

    public function getLanguage(): string;
}

TranslationsField.php

<?php

declare(strict_types=1);

namespace App\Tooling\Translation\Admin;

use App\Tooling\Translation\Form\TranslationsType;
use EasyCorp\Bundle\EasyAdminBundle\Contracts\Field\FieldInterface;
use EasyCorp\Bundle\EasyAdminBundle\Field\FieldTrait;
use Symfony\Contracts\Translation\TranslatableInterface;

class TranslationsField implements FieldInterface
{
    use FieldTrait;

    public function setValue(mixed $value): self
    {
        $this->dto->setValue($value);

        return $this;
    }

    public static function new(string $propertyName, TranslatableInterface|string|false|null $label = null): self
    {
        return (new self())
            ->setProperty($propertyName)
            ->setLabel($label)
            ->onlyOnForms()
            ->addFormTheme('Admin/Form/translations.html.twig')
            ->setRequired(true)
            ->setFormType(TranslationsType::class)
        ;
    }
}

TranslationsType.php

<?php

declare(strict_types=1);

namespace App\Tooling\Translation\Form;

use App\Tooling\Translation\AvailableLocalesProvider;
use Symfony\Component\Form\AbstractType;
use Symfony\Component\Form\Extension\Core\Type\CollectionType;
use Symfony\Component\Form\FormBuilderInterface;
use Symfony\Component\Form\FormEvent;
use Symfony\Component\Form\FormEvents;
use Symfony\Component\OptionsResolver\OptionsResolver;

class TranslationsType extends AbstractType
{
    public function __construct(private AvailableLocalesProvider $availableLocalesProvider)
    {
    }

    public function buildForm(FormBuilderInterface $builder, array $options): void
    {
        $builder->addEventListener(FormEvents::PRE_SET_DATA, function (FormEvent $event): void {
            $translations = $event->getData();
            $model = $event->getForm()->getParent()->getData();
            foreach ($this->availableLocalesProvider->getAvailableLocales() as $locale) {
                if ($translations->containsKey($locale->getCode())) {
                    continue;
                }
                $translations->set($locale->getCode(), $model->getTranslation($locale->getCode()));
            }
            $event->setData($translations);
        }, 900); // Priority 900 is important to take over on CollectionType listeners
    }

    public function configureOptions(OptionsResolver $resolver): void
    {
        $resolver->setDefaults([
            'allow_add' => false,
            'allow_delete' => false,
        ]);
    }

    public function getParent()
    {
        return CollectionType::class;
    }
}

TranslationTrait.php

<?php

declare(strict_types=1);

namespace App\Tooling\Translation\Model;

use Nekland\Tools\StringTools;
use Symfony\Component\Serializer\Annotation\Groups;

/**
 * @template T of TranslatableInterface
 */
trait TranslationTrait
{
    /**
     * @var T
     */
    private TranslatableInterface $translatable;

    #[Groups(['list-products'])]
    private string $locale;

    /**
     * @return T
     */
    public function getTranslatable(): TranslatableInterface
    {
        return $this->translatable;
    }

    public function getLocale(): string
    {
        return $this->locale;
    }

    public function setLocale(string $locale): void
    {
        $this->locale = $locale;
    }

    public function getLanguage(): string
    {
        [$language] = explode('_', $this->locale);

        return strtolower($language);
    }

    public function getCountry(): string
    {
        [,$country] = explode('_', $this->locale);

        return strtolower($country);
    }

    /**
     * @param T $translatable
     */
    public function setTranslatable(TranslatableInterface $translatable): void
    {
        $this->translatable = $translatable;
    }

    public static function getTranslatableEntityClass(): string
    {
        return StringTools::removeEnd(static::class, 'Translation');
    }
}