Invalid IRIs in output DTOs

[bpolaszek]

Hello there,

I just noticed that when using DTO output to create a different representation of the resource, the IRI returned by API-Platform is a generated one (as of API-Platform 3.x), instead of the original one (as of API-Platform 2.x).

TL; DR:

When requesting GET /api/books/1, I get

{
  "@type": "BookOutput",
  "@id": "/api/.well-known/genid/b10ecd57cce7b0b65b14"
}

instead of

{
  "@type": "Book",
  "@id": "/api/books/1"
}

Reproduction

Consider that resource:

namespace App\Entity;

use ApiPlatform\Metadata\ApiResource;
use App\State\BookProvider;
use Doctrine\ORM\Mapping as ORM;

#[ORM\Entity]
#[ApiResource(
    output: BookOutput::class,
    provider: BookProvider::class,
)]
class Book
{
    #[ORM\Id]
    #[ORM\GeneratedValue]
    #[ORM\Column]
    public ?int $id = null;

    #[ORM\Column(length: 255)]
    public ?string $name = null;
}

with the following representation:

namespace App\Entity;

final class BookOutput
{
    public ?int $id = null;
    public ?string $name = null;
    public string $isbn = 'some-hardcoded-isbn';
}

And its provider:

namespace App\State;

use ApiPlatform\Doctrine\Orm\State\CollectionProvider;
use ApiPlatform\Doctrine\Orm\State\ItemProvider;
use ApiPlatform\Metadata\CollectionOperationInterface;
use ApiPlatform\Metadata\Operation;
use ApiPlatform\State\ProviderInterface;
use App\Entity\BookOutput;
use Generator;

final readonly class BookProvider implements ProviderInterface
{
    public function __construct(
        private CollectionProvider $collectionProvider,
        private ItemProvider $itemProvider,
    ) {
    }

    public function provide(Operation $operation, array $uriVariables = [], array $context = []): Generator|BookOutput
    {
        return match ($operation instanceof CollectionOperationInterface) {
            true => $this->provideCollection($operation, $uriVariables, $context),
            false => $this->provideItem($operation, $uriVariables, $context),
        };
    }

    private function provideCollection(Operation $operation, array $uriVariables = [], array $context = []): Generator
    {
        $results = $this->collectionProvider->provide($operation, $uriVariables, $context);

        foreach ($results as $book) {
            $output = new BookOutput();
            $output->id = $book->id;
            $output->name = $book->name;

            yield $output;
        }
    }

    private function provideItem(Operation $operation, array $uriVariables = [], array $context = []): BookOutput
    {
        $book = $this->itemProvider->provide($operation, $uriVariables, $context);

        $output = new BookOutput();
        $output->id = $book->id;
        $output->name = $book->name;

        return $output;
    }
}

When running

GET http://127.0.0.1:8000/api/books/1

I expect:

{
    "@id": "\/api\/books\/1",
    "@type": "Book",
    "id": 1,
    "name": "The book of Foos",
    "isbn": "some-hardcoded-isbn"
}

But I get:

{
    "@type": "BookOutput",
    "@id": "\/api\/.well-known\/genid\/b10ecd57cce7b0b65b14",
    "id": 1,
    "name": "The book of Foos",
    "isbn": "some-hardcoded-isbn"
}

As you can see the returned IRI in @id is not valid, since it is supposed to be /api/books/1 (same as @type which is supposed to be Book, not BookOutput).
Is there something I can do to enforce this? In API-Platform 2.x DTOs, I can confirm that the expected IRIs were properly returned.