silex form validation with dependencies - php

Question

I've built a form with the silex framework that contains some checkboxes and a textfield. The user has to check at least one checkbox or write something in the textfield. Now I don't know how to validate such a dependency or better where to put the validation logic. I could add constraints to the single fields but how can I implement the dependency that either the checkboxes are validated or the textfield?
This is my validation code in the controller class.
public function validateAction(Request $request, Application $app)
{
$form = $app['form.factory']->create(new ApplicationForm());
$form->bind($request);
if ($form->isValid()) {
return $app->json(array(
'success' => true,
));
}
}
The ApplicationForm class looks like this (simplified):
class ApplicationForm extends AbstractType {
public function buildForm(FormBuilderInterface $builder, array $options) {
$builder
->add('crafts', 'choice', array(
'choices' => array(
array('drywall' => 'Drywall'),
array('painter' => 'Painter'),
array('plasterer' => 'Plasterer'),
array('carpenter' => 'Carpenter'),
array('electrician' => 'Electrician'),
array('plumber' => 'Plumber'),
array('tiler' => 'Tiler'),
array('bricklayer' => 'Bricklayer'),
),
'multiple' => true,
'expanded' => true,
'required' => false,
))
->add('craftsOther', 'text', array(
'attr' => array('class' => 'textinput', 'placeholder' => 'Other', 'maxlength' => 256),
'constraints' => array(
new Assert\Length(array('max' => 256, 'maxMessage' => $this->_errorMessages['crafts_other_max'])),
),
'required' => false,
));
}
}
Any ideas how to do this in an elegant way?

Answer 1

You can add constraints to the form itself, not just individual fields. You can pass an array of constraints in the options:
Here is a working example that checks both fields are not equal when submitted.
<?php
require_once __DIR__.'/../vendor/autoload.php';
use Silex\Application;
use Symfony\Component\Form\AbstractType;
use Symfony\Component\Form\Extension\Core\Type\SubmitType;
use Symfony\Component\HttpFoundation\Request;
use Symfony\Component\Validator\Context\ExecutionContextInterface;
use Symfony\Component\Validator\Constraints as Assert;
$app = new Application();
$app['debug'] = true;
$app->register(new \Silex\Provider\FormServiceProvider());
$app->register(new Silex\Provider\TranslationServiceProvider(), array('translator.domains' => array(),));
$app->register(new Silex\Provider\ValidatorServiceProvider());
$app->register(new Silex\Provider\TwigServiceProvider());
class ExampleFormType extends AbstractType
{
public function buildForm(\Symfony\Component\Form\FormBuilderInterface $builder, array $options)
{
$builder
->add('apple')
->add('banana')
->add('submit', SubmitType::class);
}
public function configureOptions(\Symfony\Component\OptionsResolver\OptionsResolver $resolver)
{
$resolver->setDefaults([
'constraints' => [
new Assert\Callback(function (array $data, ExecutionContextInterface $context) {
if ($data['apple'] === $data['banana']) {
$context
->buildViolation('Apple and Banana cannot be the same')
->atPath('apple')
->addViolation();
}
}),
],
]);
}
}
$app->match('/', function (Request $request, Application $app) {
$form = $app['form.factory']->create(ExampleFormType::class)->handleRequest($request);
if ($form->isValid()) {
echo "Valid Submission";
}
return $app['twig']->createTemplate('{{ form(form) }}')->render([
'form' => $form->createView(),
]);
})->method('GET|POST');
$app->run();