Symfony 5 form sanitise user text input by stripping chars - symfony-forms

Question

I have a form in symfony 5:
$builder
->add('name',TextType::class,[
'label'=>'Character Name',
'constraints'=>[
new Regex('/[\w\s]+/')
],
'required'=>false,
'attr'=>[
'class'=>'form-control'
],
'label_attr'=>[
'class'=>'form-label'
]
])->add('gender',ChoiceType::class,[
'label'=>'Gender',
'required'=>false,
'choices'=>[
'Any'=>'',
'Male'=>'Male',
'Female'=>'Female',
'Genderless'=>'Genderless',
'Unknown'=>'Unknown'
],
'attr'=>[
'class'=>'form-control'
],
'label_attr'=>[
'class'=>'form-label'
]
])->add('status',ChoiceType::class,[
'label'=>'Status',
'required'=>false,
'choices'=>[
'Any'=>'',
'Alive'=>'Alive',
'Dead'=>'Dead',
'Unknown'=>'unknown'
],
'attr'=>[
'class'=>'form-control'
],
'label_attr'=>[
'class'=>'form-label'
]
])->add('species',ChoiceType::class,[
'label'=>'Species',
'required'=>false,
'choices'=>[
'Any'=>'',
'Human'=>'Human',
'Alien'=>'Alien'
],
'attr'=>[
'class'=>'form-control'
],
'label_attr'=>[
'class'=>'form-label'
]
])->add('submit',SubmitType::class,[
'label'=>'Filter Results',
'attr'=>[
'class'=>'btn btn-primary'
]
]);
What i want to do if possible is use regex to strip special characters from the "name" field after it's submitted so the resulting field value only contains alphanumeric and spaces, so i want to run this on it:
preg_replace('/[^\w\s]/','',$name);
The closest thing i can find to do this is a model transformer but that doesn't really suit this situation as it's just a one way action.

Answer 1

You could use an EventSubscriber, just like Symfony does internally to trim the value in their TextType field (see https://github.com/symfony/symfony/blob/9045ad4bf2837e302e7cdbe41c38f1af33cbe854/src/Symfony/Component/Form/Extension/Core/EventListener/TrimListener.php ):
<?php
namespace App\Form\EventListener;
use Symfony\Component\EventDispatcher\EventSubscriberInterface;
use Symfony\Component\Form\FormEvent;
use Symfony\Component\Form\FormEvents;
class SanitizeListener implements EventSubscriberInterface
{
public function preSubmit(FormEvent $event)
{
$data = $event->getData();
if (!\is_string($data)) {
return;
}
$event->setData(preg_replace('/[^\w\s]/','',$data));
}
public static function getSubscribedEvents(): array
{
return [FormEvents::PRE_SUBMIT => 'preSubmit'];
}
}
Attach the listener to your name field like this:
$builder->get('name')->addEventSubscriber(new SanitizeListener());