Form post-processing in Symfony2 - forms

Question

I am new of Symfony, and I am trying to create a form bound to an Entity User.
One field of this entity is of type ArrayCollection. It is actually a OneToMany relationship with objects of another class.
So, a little bit of code just to be clearer.
class User
{
\\...
/**
* #ORM\OneToMany(targetEntity="UserGoods", mappedBy="users")
* #ORM\JoinColumn(name="goods", referencedColumnName="id")
*/
private $goods;
public function __construct()
{
$this->goods = new ArrayCollection();
}
\\...
}
And the associated class
class UserGoods
{
/**
* #var integer
*
* #ORM\Column(name="id", type="integer")
* #ORM\Id
* #ORM\GeneratedValue(strategy="AUTO")
*/
private $id;
/**
* #var \DateTime
*
* #ORM\Column(name="inserted_at", type="datetime")
*/
private $insertedAt;
/**
* #var float
*
* #ORM\Column(name="value", type="float")
*/
private $value;
/**
* #ORM\ManyToOne(targetEntity="User", inversedBy="goods")
*/
protected $users;
}
Now, I want to create a FormBuilder that does something extremely simple, yet I couldn't figure it out how to do it by myself.
I want just a field of type number, and if an object of type Goods with the current date exists, modify it, otherwise add a new object to the collection.
This could be easily done inside the controller, but I have a lot of instances of this form, and this would make my program impossible to maintain.
Is there a way to add some post-processing of submitted data inside the form builder?
I already tried with DataTransformers but these won't suffice, as at most they would transform a number to a UserGoods object, and the original ArrayCollection would not be preserved (and what about doctrine associations?).
In addition, if I declare the field type as collection of number types, all the items inside the ArrayCollection would be displayed when rendering the form, not just the last one.
Any idea on how to get out of this?
Thank you in advance for your help.

Answer 1

As suggested, use Form Events. Inside the event you will check if the Goods with the submitted date already exist (load them from database) and your will modify them with the post data. If they dont exist, you will be creating new ones. You can also make another method in your entity, getLastItemsInCollection(), where you can use Criteria, to only load the last one from the database (recommended), or get the last item from original ArrayCollection. You can make a field unmapped, and map the Goods manually in the FormEvent, as described above. I hope that helps and I hope I understood correctly.

Answer 2

I followed Cerad and tomazahlin suggestions and I came up with a solution.
I am sure that every year at least 2 people over the world share my same problem, so I'll take some time to post my outcome.
Feel free to correct, criticize or add me, in the end I am a newbie of Symfony!
First, how I defined my two classes in the end.
class User
{
//...
/**
* #ORM\ManyToMany(targetEntity="UserGoods", inversedBy="users", cascade={"persist", "remove"})
* #ORM\JoinColumn(name="goods", referencedColumnName="id")
*/
// Should have been a OneToMany relationship, but Doctrine requires the
// owner side to be on the Many side, and I need it on the One side.
// A ManyToMany relationship compensate this.
private $goods;
public function __construct()
{
$this->goods = new ArrayCollection();
}
//...
}
And the connected class
/**
* #ORM\HasLifecycleCallbacks()
**/
class UserGoods
{
/**
* #var integer
*
* #ORM\Column(name="id", type="integer")
* #ORM\Id
* #ORM\GeneratedValue(strategy="AUTO")
*/
private $id;
/**
* #var \DateTime
*
* #ORM\Column(name="inserted_at", type="datetime")
*/
private $insertedAt;
/**
* #var float
*
* #ORM\Column(name="value", type="float", nullable=true)
*/
// I do not want this field to be null, but in this way when
// persisting I can look for null elements and remove them
private $value;
/**
* #ORM\ManyToMany(targetEntity="User", inversedBy="goods")
*/
protected $users;
/**
* #ORM\PrePersist()
* #ORM\PreUpdate()
*/
// This automatically sets InsertedAt value when inserting or
// updating an element.
public function setInsertedAtValue()
{
$date = new \DateTime();
$this->setInsertedAt( $date );
}
}
As I said, I wanted a FormBuilder to handle my array collection. The best form type for this purpose is... collection type.
This require a subform to be defined as its type.
<?php
namespace MyBundle\Form\Type;
use Symfony\Component\Form\AbstractType;
use Symfony\Component\Form\FormBuilderInterface;
use Symfony\Component\OptionsResolver\OptionsResolverInterface;
use MyBundle\Entity\UserGoods;
class UserType extends AbstractType
{
public function buildForm(FormBuilderInterface $builder, array $options)
{
$builder->add('goods', 'collection', array(
'type' => new GoodsdataWithDateType(),
'required' => false,
)
);
\\ ...
And the subform.
Since I need only the today's value to be displayed, and not all of them, I also need to add a FormEvent clause to check which items to insert.
namespace MyBundle\Form\Type;
use Symfony\Component\Form\AbstractType;
use Symfony\Component\Form\FormBuilderInterface;
use Symfony\Component\OptionsResolver\OptionsResolverInterface;
use Doctrine\ORM\EntityManager;
use Symfony\Component\Form\FormEvent;
use Symfony\Component\Form\FormEvents;
class GoodsdataWithDateType extends AbstractType
{
public function buildForm(FormBuilderInterface $builder, array $options)
{
// Here I add the event listener:
// Since I want only today's value to be displayed, I implement
// a check on this field of each element
$builder->addEventListener(
FormEvents::PRE_SET_DATA, function (FormEvent $event) {
$goods = $event->getData();
$form = $event->getForm();
$datetime1 = $goods->getInsertedAt();
$datetime2 = new \DateTime();
$datetime2->setTime(0, 0, 0);
if ($datetime1 > $datetime2)
{
$form->add('value', 'number', array(
'required' => false,
));
// I am setting this value with LifecycleCallbacks, and I do not
// want the user to change it, I am adding it commented just for
// completeness
// $form->add('insertedAt', 'date', array(
// 'widget' => 'single_text',
// 'format' => 'yyyy,MM,dd',
// ));
}
});
}
public function setDefaultOptions(OptionsResolverInterface $resolver)
{
$resolver->setDefaults(array(
'data_class' => 'MyBundle\Entity\UserGoods',
));
}
public function getName()
{
return 'goodsdatawithdate';
}
}
This works fine, but is displayed very badly when rendered with something like {{ form(form) }} in twig files.
To make it more user-friendly, I customized how the form was presented, in order to remove some garbage and include only the labels that were necessary.
So in my twig:
{{ form_start(form) }}
{{ form_errors(form) }}
<div>
{{ form_label(form.goods) }}
{{ form_errors(form.goods) }}
<br>
{% for field in form.goods %}
{{ form_widget(field) }}
{% endfor %}
</div>
{{ form_end(form) }}
This is nice so far, but I also want to include new elements in my collection, in particular if today's good has not been inserted yet.
I can do this inside my FormBuilder, by manually add a new item in the array before calling the $builder.
class UserType extends AbstractType
{
public function buildForm(FormBuilderInterface $builder, array $options)
{
$thisuser = $builder->getData();
// I added the following function inside the User class.
// I use a for loop to scroll all the associated Goods to get the
// latest one.
$mygoods = $thisuser->getLatestGoods();
if ( $mygoods && null !== $mygoods->getId() ) {
// The Array contains already some elements
$datetime1 = $mygoods->getInsertedAt();
$datetime2 = new \DateTime();
$datetime2->setTime(0, 0, 0);
// Check when was the last one inserted
if ($datetime1 < $datetime2) // Nice way to compare dates
{
// If it is older than today, add a new element to the array
$newgoods = new UserGoods();
$thisuser->addGoods($newgoods);
}
} else {
// The array is empty and I need to create the firs element
$newgoods = new UserGoods();
$thisuser->addGoods($newgoods);
}
$builder->add('goods', 'collection', array(
'type' => new GoodsdataWithDateType(),
'required' => false,
'allow_add' => true, // this enables the array to be
// populated with new elements
)
);
But I also want that if a user removes an inserted value (i.e., inserts nothing in the form), the associated array element should be removed.
Allowing the user to remove elements is a little bit trickyer. I cannot rely on 'allow_delete' property, since by working only with the last item in the collection, all the previous ones would be removed when the form is submitted.
I cannot rely on LifecycleCallbacks neither, because the changes made to relationships are not persisted in the database.
Thankfully to open source, I found a post here that helped me.
What I needed was an EventListener on Doctrine Flush operations.
namespace MyBundle\EventListener;
use Doctrine\ORM\Event\OnFlushEventArgs;
use MyBundle\Entity\UserGoods;
class EmptyValueListener
{
public function onFlush(OnFlushEventArgs $args)
{
$em = $args->getEntityManager();
$uow = $em->getUnitOfWork();
$entities = array_merge(
$uow->getScheduledEntityInsertions(),
$uow->getScheduledEntityUpdates()
);
foreach ($entities as $entity) {
if ($entity instanceof UserGoods) {
if ($entity && null !== $entity )
{
if ( empty($entity->getValue()) )
{
$users = $entity->getUsers();
foreach ($users as $curruser)
{
$curruser->removeGoods($entity);
$em->remove($entity);
$md = $em->getClassMetadata('MyBundle\Entity\UserGoods');
$uow->computeChangeSet($md, $entity);
$em->persist($curruser);
$md = $em->getClassMetadata('MyBundle\Entity\User');
$uow->computeChangeSet($md, $curruser);
}
}
}
}
}
}
}
and registered it in my config.yml as
mybundle.emptyvalues_listener:
class: MyBundle\EventListener\EmptyValueListener
tags:
- { name: doctrine.event_listener, event: onFlush }