Entity primary key inside symfony collection - php

Question

Im learning symfony 3 & doctrine and i created a form with entity collection. Entities are Post and Tags with manyTomany relation. Main form is Post with collection of tags.
I want to pass only IDs (primary key) of tags in my collection. In result i have only one field in tag form:
$builder->add('tagId');
I created autocomplete for it, thats why i need only primary key.
After saving my form, doctrine create new tag entities with passed ids but i want to find those entities instead of creating new. Have no clue...
I was trying to make it work inside my controller:
$formTags = $form->get('tag');
foreach ($formTags->getData() as $key => $formTag)
{
// here i have new entities with id ;/
if($formTag->getTagId())
{
// so i tryied to find them, and replace it
$formTags->offsetSet($key,
array($this->getDoctrine()->getRepository('BlogBundle:Tag')
->find($formTag->getTagId())));
}
}
But symfony throw me exceptions, also with setData method. Cant change it after form is submitted. I hope you guys can help me!
i was trying to make data transformer. Forget to mention :) Problem Was that my transformer change tagId field to tag object. In result i had tag object with new entity, and instead tagId value - there was another object inside, transformed. So dont work like expected for me. I think i should make transformer for collection field instead of tag id, but have no idea how make it work. I tryied to make "tag" field inside collection and transform it, but doctrine try always to get value from entity based on fields so no getTag() method found :)

Answer 1

You can use Symfony DataTransfomer in your TagType to transform the tagId to a Tag Entity .
From Symfony DataTransformer docs :
Data transformers are used to translate the data for a field into a format that can be displayed in a form (and back on submit).
...
Say you have a many-to-one relation from the Task entity to an Issue entity (i.e. each Task has an optional foreign key to its related Issue). Adding a listbox with all possible issues could eventually get really long and take a long time to load. Instead, you decide you want to add a textbox, where the user can simply enter the issue number.

Answer 2

I made it. With data transformers, but we need to make transformer for collection, not for field inside collection.
So its look like that (works!).
My PostType.php form need to have entity manager (like inside documentation, about data transformers), and data transformer for collection, so i added:
# PostType.php form
namespace BlogBundle\Form;
use Symfony\Component\Form\AbstractType;
use Symfony\Component\Form\FormBuilderInterface;
use Symfony\Component\OptionsResolver\OptionsResolver;
use Doctrine\ORM\EntityRepository;
use Symfony\Bridge\Doctrine\Form\Type\EntityType;
use Symfony\Component\Form\Extension\Core\Type\CollectionType;
use BlogBundle\Form\DataTransformer\TagToIdTransformer;
use Doctrine\Common\Persistence\ObjectManager;
class PostType extends AbstractType
{
private $manager;
public function __construct(ObjectManager $manager)
{
// needed for transformer :(
// and we need to register service inside app config for this. Details below
$this->manager = $manager;
}
public function buildForm(FormBuilderInterface $builder, array $options)
{
$builder
->add('tag', CollectionType::class, array(
'entry_type' => TagType::class,
'by_reference' => false,
'allow_add' => true,
))
->add('save', SubmitType::class, array('label' => 'Save'));
$builder->get('tag')
->addModelTransformer(new TagToIdTransformer($this->manager));
}
}
Constructor will trow exception, we need to pass ObjectManager to it. To make it, modify config file inside your bundle:
# src/BlogBundle/Resources/config/services.yml
services:
blog.form.type.tag:
class: BlogBundle\Form\PostType
arguments: ["#doctrine.orm.entity_manager"]
tags:
- { name: form.type }
Now lets make transformer for a collection! I made it wrong before, because i was trying to make like inside documentation, for one field. For collection we need to transform whole array of tags (its manyToMany collection):
<?php
namespace BlogBundle\Form\DataTransformer;
use BlogBundle\Entity\Tag;
use Doctrine\Common\Persistence\ObjectManager;
use Symfony\Component\Form\DataTransformerInterface;
use Symfony\Component\Form\Exception\TransformationFailedException;
class TagToIdTransformer implements DataTransformerInterface
{
private $manager;
public function __construct(ObjectManager $manager)
{
$this->manager = $manager;
}
/**
* Transforms array of objects (Tag) to an array of string (number).
*
* #param array|null $tags
* #return string
*/
public function transform($tags)
{
$result = array();
if (null === $tags) {
return null;
}
foreach ($tags as $tag)
{
$result[] = $tag->getTagId();
}
return $result;
}
/**
* Transforms an array of strings (numbers) to an array of objects (Tag).
*
* #param string $tagsId
* #return Tag|null
* #throws TransformationFailedException if object (Tag) is not found.
*/
public function reverseTransform($tagsId)
{
// no issue number? It's optional, so that's ok
if (!$tagsId) {
return;
}
$result = array();
$repository = $this->manager
->getRepository('BlogBundle:Tag');
foreach ($tagsId as $tagId) {
$tag = $repository->find($tagId);
if (null === $tag) {
// causes a validation error
// this message is not shown to the user
// see the invalid_message option
throw new TransformationFailedException(sprintf(
'An tag with id "%s" does not exist!',
$tagId
));
}
$result[] = $tag;
}
return $result;
}
}
Everything works fine now. I can easy save my entities with autocomplete that populate IDs of tags only