Add code snippet into a class - php

Question

I have some function which I use in my cart application:
session_start();
if(!isset($_SESSION['products'], $_SESSION['price'], $_SESSION['product_names'],$_SESSION['product_id'])) {
$_SESSION['products'] = 0;
$_SESSION['price'] = 0;
$_SESSION['product_names'] = array();
$_SESSION['product_id'] = array();
}
if(isset($_POST['add'])) {
$_SESSION['product_names'][] = $_POST['product_name'];
$_SESSION['products']++;
$_SESSION['price'] += $_POST['price'];
}
if(isset($_POST['empty'])) {
session_destroy();
header('Location:index.php');
}
The question is, how can I add this into a class and call it in my view page?
I mean it will still work as <?php echo $_SESSION['price']?>. How can I make this work?

Answer 1

Try this class you're doing in a wrong way.
session_start();
class Shopping {
public function __construct()
{
}
//get cart products
public function getCartProducts()
{
$cart = array();
if(isset($_SESSION['cart'])) {
$cart = unserialize($_SESSION['cart']);
}
return $cart;
}
//add product to cart
public function addToCart($product_details)
{
$cart = $this->getCartProducts();
$product_id = $product_details['product_id'];
$is_quantity = $this->addQuantity($product_id); //check if product already exists in session if then increase the quantity
if(!$is_quantity) {
$product_details = array(
'qty' => $product_details['qty'],
'price' => $product_details['price'],
'product_name' => $product_details['name'],
'product_id' => $product_id
);
array_push($cart, $product_details);
$_SESSION['cart'] = serialize($cart);
}
}
//add quantity if product already exists
private function addQuantity($product_id)
{
$cart = $this->getCartProducts();
$i = 0;
foreach ($cart as $product) {
if($product['product_id'] == $product_id)
{
$product['qty'] += 1;
$cart[$i] = $product;
$_SESSION['cart'] = serialize($cart);
return true;
}
$i++;
}
return false;
}
public function clearCart()
{
unset($_SESSION['cart']);
}
public function removeProduct($product_id)
{
$cart = $this->getCartProducts();
$new_cart = array();
foreach ($cart as $product) {
if($product['product_id'] != $product_id)
array_push($new_cart, $product);
}
$_SESSION['cart'] = serialize($new_cart);
}
}
$shop = new Shopping();
$shop->addToCart(array('product_id'=>1,'name'=>'test 1','price'=>'120.00','qty'=>1));
$shop->addToCart(array('product_id'=>3,'name'=>'test 2','price'=>'120.00','qty'=>1));

Answer 2

This is an example of my approach using session in class. References work pretty well.
class Cart {
private $container ;
public function __construct(&$container){
if (!isset($container) || !is_array($container))
$session['cart'] = array() ;
$this->container = &$container ;
}
public function productExists($id){
return (isset($this->container[$id])) ;
}
}
$cart = new Cart($_SESSION['cart']) ;
At this point all changes in container can be performed in $_SESSION['cart'] . The rest of session array is not affected, that should be safe.