Symfony3 deserialize - symfony

Question

I have this entity:
AppBundle\Entity\Ciudad
class Ciudad{
...
/**
* #ORM\ManyToOne(targetEntity="AppBundle\Entity\ComunidadAutonoma")
* #ORM\JoinColumns({
* #ORM\JoinColumn(name="id_ccaa", referencedColumnName="id")
* })
*/
private $ccaa;
....
public function getCcaa()
{
return $this->ccaa;
}
public function setCcaa(ComunidadAutonoma $ccaa)
{
$this->ccaa = $ccaa;
}
}
And the other entity is:
AppBundle\Entity\ComunidadAutonoma
class ComunidadAutonoma{
properties
getters
setters
}
In a controller, I get data from a form, and I´m triying to deserialize the data into a Ciudad entity, but is getting me allways the same error:
Expected argument of type "AppBundle\Entity\ComunidadAutonoma", "integer" given
In the form data I send to the action in the controller, the value of the comunidadautonoma is the id of the selected option in a combo:
{
parameters...
ccaa:7,
parameters...
}
In my controller I have this:
<?php
use Symfony\Component\Serializer\Serializer;
use Symfony\Component\Serializer\Encoder\XmlEncoder;
use Symfony\Component\Serializer\Encoder\JsonEncoder;
use Symfony\Component\Serializer\Normalizer\ObjectNormalizer;
use AppBundle\Entity\Ciudad;
class CiudadController extends Controller
{
public function procesarAction(Request $request)
{
$encoders = array(new XmlEncoder(), new JsonEncoder());
$normalizers = array(new ObjectNormalizer());
$this->serializer = new Serializer($normalizers, $encoders);
$ciudad= $this->serializer->deserialize($parametros['parametros'], Ciudad::class, 'json');
}
}
Am I missing something?Do I need any special configuration to deserializer an entity with a relation?

Answer 1

You dont have to do anything if you properly configured a type. While creating a Form Type for your entity please add class name to your type like:
public function configureOptions(OptionsResolver $resolver)
{
$resolver->setDefaults([
'data_class' => Ciudad::class,
]);
}
And please use english naming for your projects.

Answer 2

First of all, since you are sending form data to your controller you could use Form Type classes to leverage all the power of the Symfony Form Component that will all this job for you.
Answering your specific question (and assuming you cannot/don't want to use Symfony Form Component) this error is absolutely expected. As you can see in your setCcaa function declaration inside Ciudad class:
public function setCcaa(ComunidadAutonoma $ccaa)
Because of the type-hinting (ComunidadAutonoma $ccaa) setCcaa function expects an argument of type ComunidadAutonoma. Now when Symfony serializer tries to denormalize your json object it calls setCcaa function with argument the ccaa value provided in your json (in your example is 7) which happens to be an integer. So Symfony complains that you provide an integer instead of ComunidadAutonoma type.
In order to solve this problem you have to create and use your own normalizer so that you can transform this integer to the corresponding entity object from your database. Something like this:
class EntityNormalizer extends ObjectNormalizer
{
/**
* Entity manager
* #var EntityManagerInterface
*/
protected $em;
public function __construct(
EntityManagerInterface $em,
?ClassMetadataFactoryInterface $classMetadataFactory = null,
?NameConverterInterface $nameConverter = null,
?PropertyAccessorInterface $propertyAccessor = null,
?PropertyTypeExtractorInterface $propertyTypeExtractor = null
) {
parent::__construct($classMetadataFactory, $nameConverter, $propertyAccessor, $propertyTypeExtractor);
// Entity manager
$this->em = $em;
}
public function supportsDenormalization($data, $type, $format = null)
{
return strpos($type, 'App\\Entity\\') === 0 && (is_numeric($data) || is_string($data));
}
public function denormalize($data, $class, $format = null, array $context = [])
{
return $this->em->find($class, $data);
}
}
What this normalizer does is that it checks if your data type (in this case $ccaa) is type of an entity and if the data value provided (in this case 7) is an integer, it transforms this integer to the corresponding entity object from your database (if existing).
To get this normalizer working you should also register it in your services.yaml configuration, with the appropriate tags like this:
services:
App\Normalizer\EntityNormalizer:
public: false
autowire: true
autoconfigure: true
tags:
- { name: serializer.normalizer }
You could also set the normalizer's priority but since the default priority value is equal to 0 when Symfony's built-in normalizers' priority is by default negative, your normalizer will be used first.
You could check a fully explained example of this in this fine article.