FireSyncObserver - Synchronise a Laravel Model with Firebase

FireSyncObserver.php

<?php
/**
 * FireSync Observer
 * 
 * Watch for changes and replicate them to the Firebase database
 *
 * PHP Version 7.1
 *
 * @category Observer
 * @package  Firebase
 * @license  GPLv3.0 GNU Public License v3.0
 */
namespace App\Observers;

use App\FireSync;
use Kreait\Firebase\Factory;
use Illuminate\Support\Facades\Log;

/**
 * FireSync Observer
 * 
 * Watch for changes and replicate them to the Firebase database
 *
 * @category Observer
 * @package  Firebase
 * @license  GPLv3.0 GNU Public License v3.0
 */
class FireSyncObserver
{
    private $_database;
    private $_baseReference = 'recordset/records';
    private $_reference;

    /**
     * Constructor
     */
    public function __construct()
    {
        $this->_database = (new Factory)->createDatabase();
        $this->_reference = $this->_database->getReference($this->_baseReference);
    }

    /**
     * Created event
     * 
     * Takes the newly created row and adds it to the firebase record set
     *
     * @param FireSync $fireSync The Database model
     * 
     * @return void
     */
    public function created(FireSync $fireSync)
    {
        $row = $fireSync->toArray();
        $pushKey = $this->_database->getReference(
            $this->_baseReference
        )
            ->push($row)->getKey();

        Log::debug('Create called for ' . $pushKey);
        $fireSync['push_key'] = $pushKey;
        // Call an update of the local table to add the push_key without
        // triggering any updated event.
        FireSync::withoutEvents(
            function () use ($fireSync) {
                $fireSync->save();
            }
        );
    }

    /**
     * Updated Event
     * 
     * When a row is updated update the firebase record set to match.
     * Fairly lazy as it updates ALL columns, not just those that have changed.
     *
     * @param FireSync $fireSync Database model
     * 
     * @return void
     */
    public function updated(FireSync $fireSync)
    {
        if ($fireSync['push_key'] !== null) {
            Log::debug('Update called for ' . $fireSync['push_key']);
            // Grab all the columns except push_key
            $row = $fireSync->makeHidden('push_key')->toArray();
            $this->_database->getReference(
                $this->_baseReference . '/' . $fireSync['push_key']
            )
                ->set(
                    $row
                );
        }
    }

    /**
     * Deleted Event
     * 
     * When a row is deleted remote the matching model from firebase.
     *
     * @param FireSync $fireSync Database model
     * 
     * @return void
     */
    public function deleted(FireSync $fireSync)
    {
        if ($fireSync['push_key'] !== null) {
            Log::debug('Delete called for ' . $fireSync['push_key']);
            $this->_database->getReference(
                $this->_baseReference . '/' . $fireSync['push_key']
            )
                ->remove();
        }
    }
}