Question

I made an PHP OOP Cart Class like this

print_r($_SESSION["cart"]);

the result is:

Array ( [1] => 1 [3] => 2 )

How can I print this session, like a “real” cart?
example:

echo "Your basket: ";
echo "ItemID: ".$cartid." Itemnumber:".$cartnumber;

The adding to basket part:

if (isset($_POST['submit'])) 
{ 
$cart= new Cart(); 
$cart->add($_POST['id'],2); 
$item= $cart->getCart(); 
$_SESSION["cart"]=$cart;
}

Answer 1

1. $_SESSION is just an array.
2. An array is being stored in $_SESSION[‘cart’].
3. You seem to be overwriting that array, with only the newly added item.

As an example, this code:

if (isset($_POST['submit'])) 
{ 
$cart= new Cart(); 
$cart->add($_POST['id'],2); 
$item= $cart->getCart(); 
$_SESSION["cart"]=$cart;
}

can be changed to:

if (isset($_POST['submit'])) 
{ 
$_SESSION["cart"][$_POST['id']] = 2;
}

Now, it’ll simply add to the array stored in $_SESSION[‘cart’]. Notice, that it doesn’t use the cart at all.

Try:

if (isset($_POST['submit'])) 
{ 
$cart= new Cart($_SESSION["cart"]); // this should bring in the previous items
$cart->add($_POST['id'],2); // what is this magic number '2'? Quantity?  But where is it from?
$_SESSION["cart"] = $cart->getCart();
}

Edit: Some more explanation.

The cart class’ constructor accepts a parameter that it stores internally:

private $cart;

function __construct($cart="") {
    $this->cart = $cart;
}

In all honestly, this should be a bit more intelligent:

private $cart;

function __construct($cart = array()) {
    if (is_array($cart))
    {
         $this->cart = $cart;
    }
    else
    {
         // maybe print some error, informing the developer that he's using the cart class incorrectly
         // or better yet, trigger a PHP warning:
         trigger_error('Cart class constructor expects an array parameter',      E_USER_WARNING);
    }
}

This change guards against providing anything but an array to the constructor. Note, that it can still be given an array that the class doesn’t understand, e.g. a multidimensional array. In that situation, the cart class won’t destroy existing data in the array, unless an item id matches one of the keys in the original array.