Symfony2 Form Component mutable Form Data for Survey - php

Question

I want to create a Survey that consists of multiple Questions (different implementation classes).
I would love to represent the Survey creation as well as all the Questions as FormType to make it easy to have Validation and all the good stuff from the Symfony Form Component.
It is very easy to nest forms like described here.
But now comes the tricky part:
Every Question has its own FormType and a survey should be created as well as answered (filled out by the survey taker) on one page. So all questions on one page. More or less this is like Google Forms, being able to add new Questions on one page quickly as well make it easy for the user to see all questions at once.
My 2 Question would be:
How can I add a FormType whose nested Types are known at runtime (admin can select which Question Type he wants to add)?
How can I validate and store all the Forms on one page when the survey taker fills out a survey?
I would love to hear some ideas from you.
Thanks,
Lukas

Answer 1

Use the power of Listeners. You can use almost the same flow that CollectionType uses with ResizeListener.
public function preSetData(FormEvent $event)
{
$form = $event->getForm();
$data = $event->getData();
...
foreach ($data as $name => $value) {
$form->add($name, $this->getTypeByClass($value), array_replace(array(
'property_path' => '['.$name.']',
), $this->options));
}
}
...
public function preSubmit(FormEvent $event)
{
$form = $event->getForm();
$data = $event->getData();
...
if ($this->allowAdd) {
foreach ($data as $name => $value) {
if (!$form->has($name)) {
// put special value into sub-form to indicate type of the question
$type = $value['type'];
unset($value['type']);
$form->add($name, $type, array_replace(array(
'property_path' => '['.$name.']',
), $this->options));
}
}
}
}
Try to implement the very similar flow with allowDelete, allowAdd features.
There should be another classes like SurveyData.{items, survey, ...} with n-1 relation to Survey, SurveyItem.{answer, ...} with n-1 association to QuestionAnswer. On the base of the your structure there should be written validators.
Cascade validation can be triggered with Valid constraint.
http://symfony.com/doc/current/reference/constraints/Valid.html
UPDATE
What to do to form mutable part.
public function buildForm(FormBuilderInterface $builder, array $options)
{
if ($options['allow_add'] && $options['prototyped']) {
// #var ['prototype_name' => '__name__', 'type' => 'question_type']
foreach ($options['prototypes'] as $prototype) {
$prototype = $builder->create($prototype['prototype_name'], $options['type'], $options['options']);
$prototype->add('type', 'hidden', ['data' => $options['type'], 'mapped' => false]);
$prototypes[$options['type']] = $prototype->getForm();
}
$builder->setAttribute('prototypes', $prototypes);
}
...
}
public function buildView(FormView $view, FormInterface $form, array $options)
{
$view->vars = array_replace($view->vars, array(
'allow_add' => $options['allow_add'],
'allow_delete' => $options['allow_delete'],
));
if ($form->getConfig()->hasAttribute('prototypes')) {
$view->vars['prototypes'] = $form->getConfig()->getAttribute('prototypes')->createView($view);
}
}
Now are able to use prototypes in the form block in twig.
{% for key, prototype in prototypes %}
{% set data_prototypes[key] = form_row(prototype) %}
{% endfor %}
{% set attr = attr|merge({'data-prototypes' : data_prototypes|json_encode })
Now you don't need ajax requests in JS - just use prototypes.
(var collection = $('your_collection')).append(collection.data('prototypes')[question_type].replace(/__name__/g, counter+1));
You added the element to collection, now admin can fill it and submit the form. Rest of the work (mapping data to class) will be done by Symfony.