Add extra fields using JMS Serializer bundle

I've found the solution by myself,

to add a custom field after the serialization has been done we've to create a listener class like this:

<?phpnamespace Acme\DemoBundle\Listener;use JMS\DiExtraBundle\Annotation\Service;use JMS\DiExtraBundle\Annotation\Tag;use JMS\DiExtraBundle\Annotation\Inject;use JMS\DiExtraBundle\Annotation\InjectParams;use Symfony\Component\HttpKernel\Event\PostResponseEvent;use Acme\DemoBundle\Entity\Team;use JMS\Serializer\Handler\SubscribingHandlerInterface;use JMS\Serializer\EventDispatcher\EventSubscriberInterface;use JMS\Serializer\EventDispatcher\PreSerializeEvent;use JMS\Serializer\EventDispatcher\ObjectEvent;use JMS\Serializer\GraphNavigator;use JMS\Serializer\JsonSerializationVisitor;/** * Add data after serialization * * @Service("acme.listener.serializationlistener") * @Tag("jms_serializer.event_subscriber") */class SerializationListener implements EventSubscriberInterface{    /**     * @inheritdoc     */    static public function getSubscribedEvents()    {        return array(            array('event' => 'serializer.post_serialize', 'class' => 'Acme\DemoBundle\Entity\Team', 'method' => 'onPostSerialize'),        );    }    public function onPostSerialize(ObjectEvent $event)    {        $event->getVisitor()->addData('someKey','someValue');    }}

That way you can add data to the serialized element.

Instead, if you want to edit an object just before serialization use the pre_serialize event, be aware that you need to already have a variable (and the correct serialization groups) if you want to use pre_serialize for adding a value.

I am surprised why nobody have suggested a much more easier way. You need just to use @VirtualProperty:

<?php// .../** * @JMS\VirtualProperty * @JMS\SerializedName("someField") */public function getSomeField(){    return $this->getTitle() . $this->getPromo();}

To further answer the original question. Here is how you limit added data for some serialized groups (in this example some_data is only added when we are not using the list group:

public function onPostSerializeSomeEntityJson(ObjectEvent $event) {    $entity = $event->getObject();    if (!in_array('list', (array)$event->getContext()->attributes->get('groups'))) {        $event->getVisitor()->addData('user_access', array(            'some_data' => 'some_value'        ));    }}

(array)$event->getContext()->attributes->get('groups') contains an array of the used serialized groups.