Symfony custom Argument Resolver

JsonTransformerEvent.php

<?php

declare(strict_types=1);

namespace App\Http\Event;

use App\Http\Exception\JsonMalformedException;
use Symfony\Component\EventDispatcher\Attribute\AsEventListener;
use Symfony\Component\HttpFoundation\Request;
use Symfony\Component\HttpKernel\Event\RequestEvent;
use Symfony\Component\HttpKernel\KernelEvents;

#[AsEventListener(event: KernelEvents::REQUEST, priority: 100)]
final class JsonTransformerEvent
{
    public function __invoke(RequestEvent $event): void
    {
        $request = $event->getRequest();
        if ('json' !== $request->getContentTypeFormat() || '' === $request->getContent()) {
            return;
        }

        $request->request->replace(self::transformJsonBody($request));
    }

    /** @return array<array-key, mixed> */
    private static function transformJsonBody(Request $request): array
    {
        try {
            // TODO Use Symfony Serializer component
            $data = json_decode($request->getContent(), true, flags: JSON_THROW_ON_ERROR);
        } catch (\JsonException $e) {
            throw new JsonMalformedException($e);
        }
        if (null === $data || false === is_array($data)) {
            return [];
        }

        return $data;
    }
}

RequestInterface.php

<?php

namespace App\Http\Request;

use Symfony\Component\HttpFoundation\Request;

interface RequestInterface
{
    public static function fromRequest(Request $request): self;
}

RequestResolver.php

<?php

declare(strict_types=1);

namespace App\Http\ArgumentResolver;

use App\Http\Exception\ModelValidationException;
use App\Http\Exception\RequestResolverException;
use App\Http\Request\RequestInterface;
use Symfony\Component\DependencyInjection\Attribute\AutoconfigureTag;
use Symfony\Component\HttpFoundation\Request;
use Symfony\Component\HttpKernel\Controller\ValueResolverInterface;
use Symfony\Component\HttpKernel\ControllerMetadata\ArgumentMetadata;
use Symfony\Component\Validator\Validator\ValidatorInterface;

#[AutoconfigureTag(name: 'controller.argument_value_resolver', attributes: ['priority' => 150])]
final class RequestResolver implements ValueResolverInterface
{
    public function __construct(
        private readonly ValidatorInterface $validator,
    ) {}

    public function resolve(Request $request, ArgumentMetadata $argument): array
    {
        /** @var RequestInterface $class */
        $class = $argument->getType();
        if (false === is_subclass_of($class, RequestInterface::class)) {
            return [];
        }

        try {
            $model = $class::fromRequest($request);
        } catch (\TypeError $e) {
            throw new RequestResolverException($e);
        }
        $this->validate($model);

        return [$model];
    }

    private function validate(RequestInterface $model): void
    {
        $violations = $this->validator->validate($model);
        if ($violations->count()) {
            throw new ModelValidationException($violations);
        }
    }
}

SampleControllerAction.php

<?php

declare(strict_types=1);

namespace App\Http\Action;

use App\Http\Request\SlugRequest;
use Symfony\Component\HttpFoundation\Request;
use Symfony\Component\HttpFoundation\JsonResponse;
use Symfony\Component\HttpKernel\Attribute\AsController;
use Symfony\Component\Routing\Annotation\Route;

#[AsController, Route('/news/{slug}', methods: Request::METHOD_GET)]
final class SampleControllerAction
{
    public function __invoke(SlugRequest $slugRequest): JsonResponse
    {
        // TODO Do whatever you want. You'r slug is available as getter
        
        $data = $this->repository->findBySlug($slugRequest->getSlug());
        
        return new JsonResponse(['data' => $data], 200);
    }
}

SlugRequest.php

<?php

declare(strict_types=1);

namespace App\Http\Request;

use Symfony\Component\HttpFoundation\Request;
use Symfony\Component\Validator\Constraints as Assert;

final class SlugRequest implements RequestInterface
{
    public function __construct(
        #[Assert\NotBlank]
        private readonly string $slug,
    ) {}

    public static function fromRequest(Request $request): RequestInterface
    {
        return new self($request->attributes->get('slug', ''));
    }

    public function getSlug(): string
    {
        return $this->slug;
    }
}