Event Dispatcher

Sometimes you need to change the state of the data before and/or after some serialization operation. In TSantos Serializer you can accomplish this through Event Listeners and Event Subscribers.

Event Listeners

Event listeners are single PHP methods or callable that will be called when some event is triggered by the serializer. To register listener in this bundle, first you need to create a class:

// src/EventListener/PostSerializerListener.php
namespace App\EventListener;

use TSantos\Serializer\EventDispatcher\Event\PreSerializationEvent;
use TSantos\Serializer\EventDispatcher\EventSubscriberInterface;
use TSantos\Serializer\EventDispatcher\SerializerEvents;

class PostSerializerListener
{
    public function onPreSerialization(PreSerializationEvent $event): void
    {
        $post = $event->getData();
        $post->setTitle('serialized_title');
    }
}

Then register and tag it with tsantos_serializer.event_listener:

services:
    App\EventListener\PostSerializerListener:
        tags:
            - { name: "tsantos_serializer.event_listener", event:"serializer.pre_serialization", method:"onPreSerialization" }

You can even omit the attribute method from the tag if your class is invokable by implement the __invoke method:

// src/EventListener/PostSerializerListener.php
namespace App\EventListener;

use TSantos\Serializer\EventDispatcher\Event\PreSerializationEvent;
use TSantos\Serializer\EventDispatcher\EventSubscriberInterface;
use TSantos\Serializer\EventDispatcher\SerializerEvents;

class PostSerializerListener
{
    public function __invoke(PreSerializationEvent $event): void
    {
        $post = $event->getData();
        $post->setTitle('serialized_title');
    }
}

services:
     App\EventListener\PostSerializerListener:
         tags:
             - { name: "tsantos_serializer.event_listener", event:"serializer.pre_serialization" }

Event Subscribers

A better way to define event listener is through event subscribers. All the above examples can be achieved by creating a subscriber class:

// src/EventListener/PostSerializerListener.php
namespace App\EventListener;

use TSantos\Serializer\EventDispatcher\Event\PreSerializationEvent;
use TSantos\Serializer\EventDispatcher\EventSubscriberInterface;
use TSantos\Serializer\EventDispatcher\SerializerEvents;

class PostSerializerListener implements EventDispatcherInterface
{
    public static function getListeners(): array
    {
        return [
            SerializerEvents::PRE_SERIALIZATION => 'onPreSerialization',
        ];
    }

    public function onPreSerialization(PreSerializationEvent $event): void
    {
        $post = $event->getData();
        $post->setTitle('serialized_title');
    }
}

Thanks to Symfony DIC`s auto-configuration mechanism, all you need to do is to create your subscriber class and make sure that it implements the :class:`EventDispatcher\\EventDispatcherInterface` interface.

Note

If you are using a Symfony version prior to 3.3, you’ll need to register and tag manually the service.

services:
    App\EventListener\PostSerializerListener:
        tags:
            - { name: "tsantos_serializer.event_subscriber"}