Guess custom form type when embedding custom classes - symfony

Question

Two simple classes form my app model: Money and Product.
As Money app form being reusable, I've decided to create MoneyType extending AbstractType.
// App\Entity\Product
/**
* #ORM\Embedded(class="Money\Money")
*/
private $price;
// App\Form\ProductType
$builder->add('price', MoneyType::class)
// App\Form\Type\MoneyType
class MoneyType extends AbstractType
{
private $transformer;
public function __construct(MoneyToArrayTransformer $transformer)
{
$this->transformer = $transformer;
}
public function buildForm(FormBuilderInterface $builder, array $options)
{
$builder
->add('amount', NumberType::class, [
'html5' => true,
'constraints' => [
new NotBlank(),
new PositiveOrZero(),
],
'attr' => [
'min' => '0',
'step' => '0.01',
],
])
->add('currency', ChoiceType::class, [
'choices' => $this->getCurrenciesChoices(),
'constraints' => [
new NotBlank(),
],
]);
$builder->addModelTransformer($this->transformer);
}
public function configureOptions(OptionsResolver $resolver)
{
parent::configureOptions($resolver);
$resolver->setDefaults([
'data_class' => null
]);
}
...
}
Is it possible to guess the field type without specifying it explicitly for obtaining the following code?
// App\Form\ProductType
$builder->add('price')
Any help is welcome. Thank you in advance.

Answer 1

You can implement a custom TypeGuesser that reads the doctrine metadata and checks if the field is an embeddable of the desired type. This is a basic implementation
namespace App\Form\TypeGuesser;
use App\Form\Type\MoneyType;
use Symfony\Component\Form\Guess\Guess;
use Symfony\Component\Form\Guess\TypeGuess;
use Symfony\Component\Form\FormTypeGuesserInterface;
use Doctrine\ORM\EntityManagerInterface;
class MoneyTypeGuesser implements FormTypeGuesserInterface
{
private $em;
public function __construct(EntityManagerInterface $em)
{
$this->em = $em;
}
public function guessType($class, $property)
{
if (!$metadata = $this->em->getClassMetadata($class)) {
return null;
}
if (
isset($metadata->embeddedClasses[$property]) &&
'Money\Money' == $metadata->embeddedClasses[$property]['class']
) {
return new TypeGuess(MoneyType::class, [], Guess::HIGH_CONFIDENCE);
}
}
// Other interface functions ommited for brevity, you can return null
}
You can see all the interface methods that you need to implement here.

Answer 2

The Form TypeGuesser is mostly based on the annotation #var Money\Money and you should be able to build your down guesser for your own types, see https://symfony.com/doc/current/form/type_guesser.html
Also take a look at https://github.com/symfony/symfony/blob/4.3/src/Symfony/Bridge/Doctrine/Form/DoctrineOrmTypeGuesser.php on how to guess the type by doctrine orm specific types.
You could derive your own app specific guesser with those two examples.