Where to normalize submitted form values in Symfony forms? - symfony

Question

I have a postal code field in my form, which' value should match this regex: /^[1-9][0-9]{3}\s?[a-zA-Z]{2}$/
In my entity I would like all postal codes to have the same format: 4 digits, a space and 2 uppercase letters, so the incoming value needs to be normalized somewhere.
Question: where do I do this conversion? I'm using Symfony's form system and Symfony version 5.4.9.
Entity:
class Address
{
/**
* #ORM\Column(type="string", length=7)
* #Assert\NotBlank
* #Assert\Regex(
* pattern="/^[1-9][0-9]{3}\s?[a-zA-Z]{2}$/",
* message="Deze waarde is geen geldige postcode."
* )
*/
private $postcode;
public function setPostcode(string $postcode): self
{
$this->postcode = $postcode;
return $this;
}
// other fields
}
FormType:
class AddressType extends AbstractType
{
public function buildForm(FormBuilderInterface $builder, array $options): void
{
$builder
->add('postcode', null, [
'label' => 'Postcode'
])
// other fields
;
}
public function configureOptions(OptionsResolver $resolver): void
{
$resolver->setDefaults([
'data_class' => Address::class,
]);
}
}
If I understand correctly, the form system sets incoming valid and invalid values from the form directly onto my entity (in the isSubmitted method in the controller), and after that the entity is validated (in the isValid method).
So if I add the normalization in my entity's setter (which is called in isSubmitted), I would have to manually validate the incoming value before I can normalize it, but this duplicates the regex that's later executed by isValid. Same goes if I were to use an event listener or a transformer on the form, so neither of these seem to be a great solution.
How is this usually done?

Answer 1

I ended up using an event listener as that required the least amount of extra code.
Restricted the regex on the entity like this:
class Address
{
/**
* #ORM\Column(type="string", length=7)
* #Assert\NotBlank
* #Assert\Regex(
* pattern="/^[1-9][0-9]{3} [A-Z]{2}$/",
* message="Deze waarde is geen geldige postcode."
* )
*/
private $postcode;
public function setPostcode(string $postcode): self
{
$this->postcode = $postcode;
return $this;
}
// other fields
}
And added an event listener for the PRE_SUBMIT event on the FormType:
class AddressType extends AbstractType
{
public function buildForm(FormBuilderInterface $builder, array $options): void
{
$builder
->add('postcode', null, [
'label' => 'Postcode'
])
// other fields
;
$builder->get('postcode')->addEventListener(FormEvents::PRE_SUBMIT, function (FormEvent $event) {
$data = $event->getData();
if (!\is_string($data)) {
return;
}
if (preg_match('/^([1-9][0-9]{3})\s?([a-zA-Z]{2})$/', $data, $matches)) {
$event->setData($matches[1] . ' ' . strtoupper($matches[2]));
}
});
}
}
This does change the formatting of the value that is displayed in the form in case of a submit + invalid, but I did not mind that.
If you want to keep the displayed value exactly as the user inputted it, but transform the value in the background before it is set onto the entity, you can use a ModelTransformer instead:
class AddressType extends AbstractType
{
public function buildForm(FormBuilderInterface $builder, array $options): void
{
$builder
->add('postcode', null, [
'label' => 'Postcode'
])
// other fields
;
$builder->get('postcode')
->addModelTransformer(new CallbackTransformer(
function ($modelData) {
return $modelData;
},
function ($normData) {
if (!\is_string($normData)) {
return;
}
if (preg_match('/^([1-9][0-9]{3})\s?([a-zA-Z]{2})$/', $normData, $matches)) {
return $matches[1] . ' ' . strtoupper($matches[2]);
}
return $normData;
}
))
;
}
}
Using a ViewTransformer (->addViewTransformer) with the same code as the ModelTransformer above also changes the formatting of the value that is displayed in the form, but with more code than the event listener.