When using Symfony2.1 forms, at what point should I bind custom data (an object) based on form values to my form's object? - symfony-forms

Question

Given the following scenario, where should I put logic to bind Department to Review:
Entities:
Dealership (has many departments)
Department (has one type)
DepartmentType
Review (has one dealership and one department)
On my ReviewForm I need the user to be able to select a Dealership and a DepartmentType, and then in some form of callback or pre/post bind, work out from them which Department to bind to the Review.
I also need this to happen prior to validation so that I can validate that the Department is child of the Dealership.
Note: Review relates to both Dealership and Department when it could just relate to Department to ease traversal and other logic I have going on.
There are two approaches I've tried so far but reached deadends / confusion.
DataTransformer on the DepartmentType on the form, not sure I understand this properly, my transform / reverseTransform methods were getting passed in the Review object, not the field object.
PRE_BIND, happens before validation but I only have raw data to work with, no objects
POST_BIND, happens after validation :(
For the final step of validation of the relationship I have a relatively simple validator that should do the job, but I'm not sure at what point I am meant to bind data to the object like this. Any pointers?

Answer 1

As validation is also done in a POST_BIND listener, you could simply add your POST_BIND listener with a higher priority than the validation listener (i.e. anything > 0).
If you're writing a listener:
$builder->addEventListener(FormEvents::POST_BIND, $myListener, 10);
and if you're writing a subscriber:
public static function getSubscribedEvents()
{
return array(
FormEvents::POST_BIND => array('postBind', 10),
);
}
public function postBind(FormEvent $event)
{
...
}

Answer 2

I would go with a standard (ie: non-Doctrine) choice type containing a choice to represent each DepartmentType.
Then use a DataTransformer to turn the selected option into the relevant type, and vice versa.
Your custom FormType should end up looking something like this:
class Department extends AbstractType
{
private $em;
public function __construct(EntityManager $em) {
$this->em = $em;
}
public function buildForm(FormBuilderInterface $builder, array $options)
{
$transformer = new DepartmentToTypeTransformer($this->em);
$builder->addViewTransformer($transformer, true);
$builder->getParent()->addEventListener(FormEvents::PRE_BIND, function($event) use ($transformer) {
$data = (object) $event->getData();
$transformer->setDealership($data->dealership);
});
}
public function getParent()
{
return 'choice';
}
public function getName()
{
return 'department';
}
public function setDefaultOptions(OptionsResolverInterface $resolver)
{
$choices = array();
foreach ($this->em->getRepository('AcmeDemoBundle:DepartmentType')->findAll() as $type) {
$choices[$type->getId()] = (string) $type;
}
$resolver->setDefaults(array(
'choices' => $choices,
'expanded' => true
));
}
}
Note the passing of the Dealership into the DataTransformer for use in the transformation.
And DataTransformer something like this:
class DepartmentToTypeTransformer implements DataTransformerInterface
{
private $em;
private $dealership;
public function __construct($em)
{
$this->em = $em;
}
public function transform($department)
{
if (null === $department) {
return $department;
}
return $department->getType()->getId();
}
public function reverseTransform($type)
{
if (null === $type) {
return $type;
}
return $this->em->getRepository('AcmeDemoBundle:Department')->findOneBy(array(
'dealership' => $this->getDealership(),
'type' => $type
));
}
public function getDealership() {
return $this->dealership;
}
public function setDealership($dealership) {
$this->dealership = $dealership;
return $this;
}
}
Your confusion regarding what is being passed to your transformer is most likely caused by the transformer you're binding being appended to pre-existing behaviour, try adding true as the second parameter to addViewTransformer:
$transformer = new DepartmentToTypeTransformer($this->em);
$builder->addViewTransformer($transformer, true);
From the docs:
FormBuilder::addViewTransformer(
DataTransformerInterface $viewTransformer,
Boolean $forcePrepend = false
)
Appends / prepends a transformer to the view transformer chain.