Form Class for Silex

controllers.php

<?php
use Symfony\Component\HttpFoundation\Request;
use Forms\DateRange;

$app->match('/sandbox', function(Request $req) use($app)
{
    $form = $app['form.factory']->createNamedBuilder(null, new DateRange())
        ->getForm();
    return $app['twig']->render('sandbox.html',
            array('form' => $form->createView(),
            'params' => $req->request->get('date_start') . '&' . $req->request->get('date_end'))
        );
})->method('GET|POST');

DateRange.php

<?php
namespace Forms;
use Symfony\Component\Form\AbstractType;
use Symfony\Component\Form\FormBuilderInterface;

/**
 * Builds a form to select a date range
 *
 * @author Jesús Franco Martínez
 */
class DateRange extends AbstractType
{
  public function buildForm(FormBuilderInterface $builder, array $options)
  {
    return $builder
      ->add('date_start', 'date', array(
      'required' => true,
      'widget' => 'single_text',
      'format' => 'yyyy-MM-dd',
      'label' => 'Fecha inicial'
      ))
      ->add('date_end', 'date', array(
      'required' => true,
      'widget' => 'single_text',
      'format' => 'yyyy-MM-dd',
      'label' => 'Fecha final'
      ));
  }
  public function getName()
  {
    return 'date_range';
  }
}

sandbox.html

{% extends "layout.html" %}
{% block title %}date range sandbox{% endblock %}
{% block content %}
<div class="controls">
    {{ form_start(form) }}
    <span class="row">
        {{ form_label(form.date_start) }}
        {{ form_errors(form.date_start) }}
        {{ form_widget(form.date_start) }}
    </span>
    <span class="row">
        {{ form_label(form.date_end) }}
        {{ form_errors(form.date_end) }}
        {{ form_widget(form.date_end) }}
    </span>
    <input type="submit" value="Consulta" />
    {{ form_widget(form) }}
    {{ form_end(form) }}
</div>
<p>Current parameters: {{ params }}</p>
{% endblock %}
{% block javascripts %}
{{ parent() }}
<script>
(function($) {
    $.datepicker.setDefaults(
        $.extend(
            $.datepicker.regional['es'],
            {'dateFormat':'yy-mm-dd'}
        )
    );
    $(document).ready(function() {
        $( "#date_start" ).datepicker();
        $( "#date_end" ).datepicker();
    });
})(jQuery);
</script>
{% endblock %}