Yii2 creates new session instead of opening existing - php

Question

I am working on a simple logic of storing my shopping cart in session using Yii2 native yii\web\Session.
Every time I add an item to a cart I call a method:
public function actionAdd( ) {
$id = Yii::$app->request->get('id');
$product = Product::findOne($id);
$session = Yii::$app->session;
$session->open();
$cart = new Cart();
$cart->addToCart($product);
$this->layout = false;
return $this->render('cart-modal', compact('session'));
}
this method works with a Cart model and adds my item to the session:
public function addToCart($product, $qty = 1) {
if(isset($_SESSION['cart'][$product->id])) {
$_SESSION['cart'][$product->id]['qty'] += $qty;
} else {
$_SESSION['cart'][$product->id] = [
'qty' => $qty,
'title' => $product->title,
'price' => $product->price,
'image' => $product->image,
];
}
}
and all goes well until I try add another item.
Then Yii instead of opening existing session creates a new one with this last item I've add. What can be the reason of this kind of behavior?
I'm working on a local web server OpenServer and haven't changed any setting that might be related to sessions.

Answer 1

You are basically not using session component at all. Change your code to:
public function actionAdd( ) {
$id = Yii::$app->request->get('id');
$product = Product::findOne($id);
// REMOVE THIS
// session is started automatically when using component
// $session = Yii::$app->session;
// $session->open();
$cart = new Cart();
$cart->addToCart($product);
$this->layout = false;
return $this->render('cart-modal', compact('session'));
}
public function addToCart($product, $qty = 1) {
$session = Yii::$app->session;
if ($session->has('cart')) {
$cart = $session['cart']; // you can not modify session subarray directly
} else {
$cart = [];
}
if(isset($cart[$product->id])) {
$cart[$product->id]['qty'] += $qty;
} else {
$cart[$product->id] = [
'qty' => $qty,
'title' => $product->title,
'price' => $product->price,
'image' => $product->image,
];
}
$session->set('cart', $cart);
}
I hope it helps. If not it means problem is somewhere else but nevertheless you should use session component properly.

Answer 2

Ok, I've figured. The problem was with my server. As soon as I moved to VPS this issue has gone.