API Platform Serialization issue for custom Output - symfony

Question

I have created this resource in order to request a password reset token:
POST {{api_base_url}}/users/password/reset-request
Payload example
{
"email" :"user#example.com"
}
Everything works fine but the response doesn't serialize ResetPasswordRequestOutput to show the result. I got this response instead (as User type)
{
"#context": {
"#vocab": "http://dev.api.xxxxxxxxxx.com/docs.jsonld#",
"hydra": "http://www.w3.org/ns/hydra/core#",
"token": "ResetPasswordRequestOutput/token"
},
"#type": "User",
"#id": "/users/00000000-0000-0000-0000-000000000002",
"token": "ORGOsGh01sr8R91J"
}
Expected output: (of type: ResetPasswordRequestOutput)
{
"#type": "ResetPasswordRequestOutput",
"token": "ORGOsGh01sr8R91J"
}
Code:
The controller class of the custom operation:
final class ResetPasswordRequest {
private $validator;
private $entityManager;
public function __construct(ValidatorInterface $validator, EntityManagerInterface $entityManager)
{
$this->entityManager = $entityManager;
$this->validator = $validator;
}
public function __invoke(ResetPasswordRequestInput $data)
{
$this->validator->validate($data);
$userRepository = $this->entityManager->getRepository(User::class);
/** #var User $user */
$user = $userRepository->findOneBy(['email' => $data->email]);
if (!$user) {
throw new ItemNotFoundException("invalid token");
}
if ($user->getStatus() !== UserStatus::ACTIVE) {
throw new AccessDeniedException("user is inactive");
}
$generator = (new Factory())->getGenerator(new Strength(Strength::MEDIUM));
$token = $generator->generateString(16, 'BCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789');
$user->setToken($token);
return $user;
}
}
The data transofrmer that converts User object to ResetPasswordRequestOutput
namespace App\DataTransformer;
final class ResetPasswordRequestOutputDataTransformer implements DataTransformerInterface
{
private $normalizer;
public function __construct(NormalizerInterface $normalizer)
{
$this->normalizer = $normalizer;
}
/**
* {#inheritdoc}
*/
public function transform($data, string $to, array $context = [])
{
$output = new ResetPasswordRequestOutput();
$output->token = $data->getToken();
return $output;
}
/**
* {#inheritdoc}
*/
public function supportsTransformation($data, string $to, array $context = []): bool
{
return ResetPasswordRequestOutput::class === $to && $data instanceof User;
}
DTO object that holds input data
<?php
namespace App\Dto;
final class ResetPasswordRequestInput
{
/**
* #var string
*
* #Assert\Email
* #Groups({"user:write"})
*/
public $email;
}
DTO object that holds output data
namespace App\Dto;
final class ResetPasswordRequestOutput
{
/**
* #var string
*
* #Assert\NotNull()
* #Groups({"user:read"})
*/
public $token;
}
User Entity class with ApiResource annotation (partial) action=reset_password_request
/**
* #ApiResource(
* normalizationContext={"groups"={"user", "user:read"}},
* denormalizationContext={"groups"={"user", "user:write"}},
* collectionOperations={
* "get",
* "post",
* "reset_password_request" = {
* "method"= "POST",
* "read"=false,
* "path"="/users/password/reset-request",
* "controller"=ResetPasswordRequest::class,
* "status"=200,
* "input"=ResetPasswordRequestInput::class,
* "output"=ResetPasswordRequestOutput::class,
* "normalization_context"={"jsonld_embed_context"=false}
* },