CakePHP3 - Cookie Value not being kept - cakephp

Question

I have a problem where the value for the cookie I set is not being kept if switching to a different section (controller) with CakePHP3.
I establish the original cookie in the AppController so it is sitewide:
<?php
namespace App\Controller;
use Cake\Controller\Controller;
use Cake\Event\Event;
use Cake\Http\Cookie\Cookie;
use Cake\Http\Cookie\CookieCollection;
class AppController extends Controller
{
public function initialize()
{
parent::initialize();
$this->loadComponent('RequestHandler');
$this->loadComponent('Flash');
$this->loadComponent('Cookie');
//set up initial cart cookie
$this->response = $this->response->withCookie(
(new Cookie('cart'))
->withPath('/')
->withValue(json_encode([]))
->withExpiry(new \DateTime('+1 month'))
);
}
I then have it set up in the CartController to add selected items to the cart cookie:
<?php
// src/Controller/CartController.php
namespace App\Controller;
use Cake\I18n\Time;
use Cake\Http\Cookie\Cookie;
use Cake\Http\Cookie\CookieCollection;
class CartController extends AppController
{
public function index()
{
$cart = json_decode($this->request->getCookie('cart'));
$add_cart = ($this->request->getQuery('add') == null ? [] : $this->request->getQuery('add'));
if (count($add_cart) > 0) {
foreach($add_cart as $ac) {
if(!in_array($ac, $cart)) {
$cart[] = $ac;
}
}
}
//replace cookie
$this->response = $this->response->withCookie(
(new Cookie('cart'))
->withPath('/')
->withValue(json_encode($cart))
->withExpiry(new \DateTime('+1 month'))
);
$this->loadModel('Books');
$cart_items = [];
foreach($cart as $cartp) { //'contain' => ['BookTypes'],
$book = $this->Books->get($cartp, ['fields' => array('id','name','description')]);
$cart_items[] = $book;
}
$this->set(compact('cart_items'));
}
If I stay within "Cart", the cookie keeps the value. However, as soon as I move to any other page (home page or browsing books), the cookie value is reset to empty (an empty array).
What is causing this?

Answer 1

I found my problem.
Had to move the initial cookie from the initialize() to beforeFilter() in AppController.php and now it seems to be working.