Sensio ParamConverter STI abstract

Question

Given an Single Table Inheritance for Location -> A and Location -> B

 * @DiscriminatorMap({
 *     "a" = "A",
 *     "b" = "B"
 * })
 * @Discriminator(field = "discr", map = {
 *     "a" = "A",
 *     "b" = "B",
 * })
abstract class Location 

In the Controller, i will send either an A or B type extending Location.

  /**
   * @Rest\Post("", name="create_l")
   * @ParamConverter("location", converter="fos_rest.request_body")
   */
  public function insert(Location $location): JsonResponse

Doctrine tells me the obvious message it cant instaniiate an abstract class, which is true but it should instead create the subtype.

If A comes in, it should be converted to A, not instantiiate Location.

Any solutions?

Answer 1

So, after doing some research and testing i fixed it myself.

My core problem was that i mixed two Serializers, JMS and Symfony/Serializer. So i decided to go with the Symfony/Serializer as it enabled the creation of the subtypes of abstract classes. This is my setup:

Imports & Entity:

use Symfony\Component\Serializer\Annotation\DiscriminatorMap;
use Doctrine\ORM\Mapping as ORM;
use Doctrine\ORM\Mapping\DiscriminatorColumn;
use Doctrine\ORM\Mapping\InheritanceType;

/**
 * @ORM\Entity(repositoryClass=AbstractParent::class)
 * @InheritanceType("SINGLE_TABLE")
 * @DiscriminatorColumn(name="discr", type="string")
 * @DiscriminatorMap(typeProperty="discr", mapping = {
 *     "a"      = "App\Entity\A",
 *     "b"      = "App\Entity\B",
 * })
 * @ORM\Table(
 *    name="abstract_parent",
 * )
 */
abstract class AbstractParent extends PlaceComputable

When sending a post request to save a subtype:

/**
 * @Rest\Post("", name="create_subtype")
 * @ParamConverter("subtype", converter="fos_rest.request_body")
 */
public function insert(AbstractParent $subtype): JsonResponse
{
 // $subtype is now of Either Type 'A' or 'B'
 // depending on what 'discr' member was passed to the controller
}

Its is now also documented in the Symfony/Serializer documentation as to how convert subtypes of abstract classes.