framework/src/Extend/SerializeAttributes.php

<?php namespace Flarum\Extend;

use Illuminate\Contracts\Container\Container;

class SerializeAttributes implements ExtenderInterface
{
    protected $serializer;

    protected $callback;

    public function __construct($serializer, $callback)
    {
        $this->serializer = $serializer;
        $this->callback = $callback;
    }

    public function extend(Container $container)
    {
        $container->make('events')->listen('Flarum\Api\Events\SerializeAttributes', function ($event) {
            if ($event->serializer instanceof $this->serializer) {
                call_user_func_array($this->callback, [&$event->attributes, $event->model, $event->serializer]);
            }
        });
    }
}