How to use the Symfony validator bundle to validate forms?

@darrion.kuhn 

To use the Symfony Validator Bundle to validate forms, you can follow these steps:

1. Install the Validator Bundle:composer require symfony/validator
2. Create a form class with the desired fields and validation rules:use SymfonyComponentFormAbstractType; use SymfonyComponentFormExtensionCoreTypeTextType; use SymfonyComponentFormFormBuilderInterface; use SymfonyComponentValidatorConstraintsNotBlank; use SymfonyComponentValidatorConstraintsLength; class ContactFormType extends AbstractType { public function buildForm(FormBuilderInterface $builder, array $options) { $builder ->add('name', TextType::class, [ 'constraints' => [ new NotBlank(), new Length(['min' => 2, 'max' => 255]) ] ]) ->add('email', TextType::class, [ 'constraints' => [ new NotBlank(), new Email() ] ]) ->add('message', TextType::class, [ 'constraints' => [ new NotBlank(), new Length(['min' => 10, 'max' => 1000]) ] ]); } }
3. In your controller, create an instance of the form and handle its submission:use SymfonyBundleFrameworkBundleControllerAbstractController; use SymfonyComponentHttpFoundationRequest; use SymfonyComponentRoutingAnnotationRoute; use SymfonyComponentFormExtensionCoreTypeSubmitType; class ContactController extends AbstractController { /** * @Route("/contact", name="contact") */ public function contact(Request $request) { $form = $this->createForm(ContactFormType::class) ->add('submit', SubmitType::class); $form->handleRequest($request); if ($form->isSubmitted() && $form->isValid()) { // Do something with the form data } return $this->render('contact.html.twig', [ 'form' => $form->createView() ]); } }
4. In your template, render the form with its fields and validation errors:{{ form_start(form) }} {{ form_row(form.name) }} {{ form_row(form.email) }} {{ form_row(form.message) }} {{ form_row(form.submit) }} {{ form_end(form) }} {% if form.errors|length > 0 %} <ul> {% for error in form.errors %} <li>{{ error.message }}</li> {% endfor %} </ul> {% endif %}

That's it! Now the form will be validated automatically based on the rules defined in the form class, and any validation errors will be displayed in the template.