DTOs & Hydration

Defining a DTO

Annotate a readonly class with #[Dto] and declare constructor parameters with validation attributes:

use Antares\Validation\Attributes\Dto;
use Antares\Validation\Attributes\NotBlank;
use Antares\Validation\Attributes\Email;
use Antares\Validation\Attributes\MinLength;
use Antares\Validation\Attributes\In;

#[Dto]
readonly class CreateUserRequest
{
    public function __construct(
        #[NotBlank]
        #[MinLength(2)]
        public string $name,

        #[NotBlank]
        #[Email]
        public string $email,

        #[In(['admin', 'editor', 'viewer'])]
        public string $role = 'viewer',
    ) {}
}

Hydrating

$data = ['name' => 'John', 'email' => 'john@example.com'];
$dto = $hydrator->hydrate(CreateUserRequest::class, $data);

$dto->name;  // 'John'
$dto->email; // 'john@example.com'
$dto->role;  // 'viewer' (default)

Strict Mode

Add #[Strict] to enable strict type checking during hydration. Without it, the hydrator coerces compatible types (e.g. "42" → 42). With it, a type mismatch throws a HydrationException:

#[Dto]
#[Strict]
readonly class StrictRequest
{
    public function __construct(
        public int $count,
    ) {}
}

Nested DTOs

DTOs can contain other #[Dto] classes as nested properties. The hydrator recurses into them automatically:

#[Dto]
readonly class AddressRequest
{
    public function __construct(
        #[NotBlank] public string $street,
        #[NotBlank] public string $city,
    ) {}
}

#[Dto]
readonly class CreateOrderRequest
{
    public function __construct(
        #[NotBlank] public string $sku,
        public AddressRequest $address,
    ) {}
}