Silex: redirect onchange select button (using URL Generator)

Question

I'm using the Silex Framework. I'm creating a system where users can answer my questions. And I've got the following route set up:

$routes->match('/assignment/register/{type}/{count}', function (Request $request, $type, $count) use ($app) {

Now, there can be two types of questions: Multiple Choice or Open. The type of the route is either MC or OP. So, the form will be generated like this:

if($type == 'MC'){

        $builder->add('type', ChoiceType::class, array(
            'label' => 'Type',
            'required' => 'required',
            'attr' => array('class' => 'select-field', 'autocomplete' => 'off', 'onchange' => 'this.form.submit()'),
            'label_attr' => array('class' => 'label'),
            'choices' => array('Multiple Choice' => 'MC', 'Open' => 'OP'),
            'expanded' => false,
            'multiple' => false,
        ));

    }
    if($type == 'OP'){

        $builder->add('type', ChoiceType::class, array(
            'label' => 'Type',
            'required' => 'required',
            'attr' => array('class' => 'select-field', 'autocomplete' => 'off', 'onchange' => 'this.form.submit()'),
            'label_attr' => array('class' => 'label'),
            'choices' => array('Multiple Choice' => 'MC', 'Open' => 'OP'),
            'expanded' => false,
            'multiple' => false,
            'data' => 'OP',
        ));

    }

However, I want to be redirected when I choose for another type of question. So let's say I'm on the MC question, how can I be redirected to the OP page when I select OP in the select box? I thought something should be done with onchange='' . But I have no clue on how to continue.

Update

When I change the select button I 'd like to be redirected to the New URL:

Let's say I'm on the multiple choice page:

Www.MyWebsite.nl/Escape/public/assignment/create/MC/3

MC stands for multiple choice, and the 3 tells the script that I can give 3 answers.

Now when I set the select to Open Question (OP) I need to be redirected to this URL:

Www.MyWebsite.nl/Escape/public/assignment/create/OP/1

This has to be done using the URL generator in Silex/Symfony, because I can't just give the full URL

update 2

I've now got the following piece of code in my twig template. However, it still doesn't execute when I change my select box:

{% block scripts %}
    {% if urlTo is defined %}
          <script>
          var urlTo = {{ urlTo }}; 
          document.getElementById('form_type').onchange(function()
          {
            alert(urlTo);
            window.location.href(urlTo);
          });
        </script>
    {% endif %}
{% endblock %}

The URL is given perfectly. I've tested that, so that part does work. Where is my mistake?

Answer 1

To pass the URL from the controller to your script you just need to attach a template variable like so:

<?php
// somwhere in your route definition file
$app->match(
    '/assignment/register/{type}/{count}', 
    function (Request $request, $type, $count) use ($app) {
      // do your magic here
      $urlTo = $app['url_generator']->generate('path-name', [$path=>$options]);

      // here you pass the $urlTo variable to your template
      // by passing a 2n argument to the render method
      // https://silex.sensiolabs.org/doc/2.0/providers/twig.html#usage
      return $app['twig']->render('your-template-name-here.twig', ["urlTo" => $urlTo]);
    }
);

And then in your template where you define your JS (assuming you are using Twig, you have not specified on which templating are you using):

<?php
// this is your template file
<script>
  var urlTo = {{ urlTo }}; // here comes the injection from the PHP value to JS
  document.getElementById('the-id-of-the-select-element').onchange = function(e) {
    // probably you want to check the selected value here and then...
    window.location.replace(urlTo);
  };
</script>

This is a bare minimum skeleton to show how to pass the urlTo PHP variable into your template and convert it into a JS variable. From here on, you should elaborate on that and adapt this code to your use case.