Symfony2 JMSSerializerBundle expose property in YML - symfony

Question

I want to expose only a few properties of my User class, using JMSSerializerBundle and FOSRestBundle.
It seems like the serializer bundle is not reading my configuration file.
My User class is in src/AppBundle/Entity/User and it extends the FOSUserBundle user class.
Here is my User class:
<?php
namespace AppBundle\Entity;
use Doctrine\ORM\Mapping as ORM;
use FOS\UserBundle\Model\User as BaseUser;
use Symfony\Component\Validator\Constraints as Assert;
/**
* User
*
* #ORM\Table(name="backoffice_user")
* #ORM\Entity(repositoryClass="AppBundle\Entity\Repository\UserRepository")
*/
class User extends BaseUser
{
/**
* #var integer
*
* #ORM\Column(name="id", type="integer")
* #ORM\Id
* #ORM\GeneratedValue(strategy="AUTO")
*/
protected $id;
/**
* #var string
*
* #ORM\Column(name="lastname", type="string", length=70)
*/
private $lastname;
/**
* #var string
*
* #ORM\Column(name="firstname", type="string", length=70)
*/
private $firstname;
}
This is my app/config.yml file
jms_serializer:
metadata:
debug: true
auto_detection: true
And the yml mappgin file in src/AppBundle/Resources/config/serializer/Entity.User.yml :
AppBundle\Entity\User:
exclusion_policy: ALL
exclude: true
properties:
email:
exclude: true
expose: true
The file is not read (or at least not taken into account), because my API returns me all fields of my entity.
Am I forgetting something ?

Answer 1

Your mapping file is not loaded, because the serializer applies the rules to the class where the properties are defined. In your case - that is FOS\UserBundle\Model\User. What you need is to override the Third-Party Metadata - a brief sample can be seen in bundle's documentation
In your config.yml, jms_serializer should probably look like this:
jms_serializer:
metadata:
auto_detection: true
directories:
FOSUserBundle:
namespace_prefix: "FOS\\UserBundle"
path: "#AppBundle/Resources/config/serializer"
Inside directory serializer you should have a file named Model.User.yml with configuration like this:
FOS\UserBundle\Model\User:
exclusion_policy: ALL
# add your desired configuration below.

Answer 2

In JMSSerializer you need to have one file for each class of the hierarchy.
So, the exclusion policy only apply to properties id, lastname and firstname; for BaseUser it use the default rule, which is to include everything.
To override a configuration file from another bundle, you first need to setup the folder for the namespace in the configuration with:
jms_serializer:
metadata:
directories:
FOSUB:
namespace_prefix: "FOS\\UserBundle"
path: "%kernel.root_dir%/serializer/FOSUB"
And add the serializer config file in app/serializer/FOSUB/Model.User.yml. See the official docs for other configurations option.