Memory management Symfony forms and Doctrine - php

Question

When building a form using Symfony the build of the form is terribly slow and the memory spikes.
The form is build using some subforms and uses some one-to-many relations. When the data of the form becomes larger (more entities in the many side) the form is slower and memory is usage is getting larger this seem okey though the amount of time and memory usage don't seem to.
Example when having about 71 enities in the many side the memory usage is about 116 MB and takes 14 seconds to load.
I already deduced the number of queries done (from 75 to 4) though the memory spike still happens the moment the form is created
$form = $this->createForm(new TapsAndAppliancesType(), $taps);
Any tips and tricks to speed this up?

Answer 1

I assume you use type entity in your form. They are quite heavy, since first all entities are fetched as objects and then reduced to some id => label style.
So you could write your own entityChoice type, which works with an id => label -array (so nothing is fetched as an object in the frist place) and add a DataTransformer to this type:
use Symfony\Component\Form\AbstractType;
use Symfony\Component\Form\FormBuilderInterface;
use Symfony\Component\OptionsResolver\OptionsResolverInterface;
use MyNamespace\EntityToIdTransformer;
class EntityChoiceType extends AbstractType
{
public function buildForm(FormBuilderInterface $builder, array $options)
{
$builder->addModelTransformer(new EntityToIdTransformer($options['repository']));
}
public function setDefaultOptions(OptionsResolverInterface $resolver)
{
$resolver->setDefaults(array(
'empty_value' => false,
'empty_data' => null,
));
$resolver->setRequired(array(
'repository'
));
}
public function getParent()
{
return 'choice';
}
public function getName()
{
return 'entityChoice';
}
}
And as DataTransformer:
use Doctrine\ORM\EntityRepository;
use Symfony\Component\Form\DataTransformerInterface;
use Symfony\Component\Form\Exception\TransformationFailedException;
class EntityToIdTransformer implements DataTransformerInterface
{
private $entityRepository;
public function __construct(EntityRepository $entityRepository)
{
$this->entityRepository = $entityRepository;
}
/**
* #param object|array $entity
* #return int|int[]
*
* #throws TransformationFailedException
*/
public function transform($entity)
{
if ($entity === null) {
return null;
}
elseif (is_array($entity) || $entity instanceof \Doctrine\ORM\PersistentCollection) {
$ids = array();
foreach ($entity as $subEntity) {
$ids[] = $subEntity->getId();
}
return $ids;
}
elseif (is_object($entity)) {
return $entity->getId();
}
throw new TransformationFailedException((is_object($entity)? get_class($entity) : '').'('.gettype($entity).') is not a valid class for EntityToIdTransformer');
}
/**
* #param int|array $id
* #return object|object[]
*
* #throws TransformationFailedException
*/
public function reverseTransform($id)
{
if ($id === null) {
return null;
}
elseif (is_numeric($id)) {
$entity = $this->entityRepository->findOneBy(array('id' => $id));
if ($entity === null) {
throw new TransformationFailedException('A '.$this->entityRepository->getClassName().' with id #'.$id.' does not exist!');
}
return $entity;
}
elseif (is_array($id)) {
if (empty($id)) {
return array();
}
$entities = $this->entityRepository->findBy(array('id' => $id)); // its array('id' => array(...)), resulting in many entities!!
if (count($id) != count($entities)) {
throw new TransformationFailedException('Some '.$this->entityRepository->getClassName().' with ids #'.implode(', ', $id).' do not exist!');
}
return $entities;
}
throw new TransformationFailedException(gettype($id).' is not a valid type for EntityToIdTransformer');
}
}
And finally register the FormType as new Type in service.yml
services:
myNamespace.form.type.entityChoice:
class: MyNamespace\EntityChoiceType
tags:
- { name: form.type, alias: entityChoice }
You can then use it in your form as
$formBuilder->add('appliance', 'entityChoice', array(
'label' => 'My Label',
'repository' => $repository,
'choices' => $repository->getLabelsById(),
'multiple' => false,
'required' => false,
'empty_value' => '(none)',
))
with $repository as an instance of your desired repository and 'choices' as an array with id => label