php update quantity on cart page

Question

I want to update the quantity of an item in the cart

These are the actions:

   if(!empty($_GET["action"])) {
    switch($_GET["action"]) {
        case "add":
            if(!empty($_POST["quantity"])) {
                $productByCode = $db_handle->runQuery("SELECT * FROM menu WHERE item_code='" . $_GET["code"] . "'");
                $itemArray = array($productByCode[0]["item_code"]=>array('name'=>$productByCode[0]["item_name"], 'code'=>$productByCode[0]["item_code"], 'quantity'=>$_POST["quantity"], 'price'=>$productByCode[0]["item_price"]));

                if(!empty($_SESSION["cart_item"])) {
                    if(in_array($productByCode[0]["item_code"],$_SESSION["cart_item"])) {
                        foreach($_SESSION["cart_item"] as $k => $v) {
                                if($productByCode[0]["item_code"] == $k)
                                    $_SESSION["cart_item"][$k]["quantity"] = $_POST["quantity"];
                        }
                    } else {
                        $_SESSION["cart_item"] = array_merge($_SESSION["cart_item"],$itemArray);
                    }
                } else {
                    $_SESSION["cart_item"] = $itemArray;
                }
            }
        break;

        case "remove":
            if(!empty($_SESSION["cart_item"])) {
                foreach($_SESSION["cart_item"] as $k => $v) {
                        if($_GET["code"] == $k)
                            unset($_SESSION["cart_item"][$k]);              
                        if(empty($_SESSION["cart_item"]))
                            unset($_SESSION["cart_item"]);
                }
            }
        break;
        case "empty":
            unset($_SESSION["cart_item"]);
        break;  
    }
    }

This is the cart code:

<?php       
    foreach ($_SESSION["cart_item"] as $item){
        ?>
                <tr>
                <td><strong><?php echo $item["name"]; ?></strong></td>
                <td><?php echo $item["quantity"]; ?></td>
                <td><?php echo "&#8377;".$item["price"]; ?></td>
                <td><a id="remove" href="index.php?action=remove&code=<?php echo $item["code"]; ?>"><span class="fa fa-times fa-lg" style="color:red;"></span></a></td>
                </tr>
                <?php
        $item_total += ($item["price"]*$item["quantity"]);
        }
        ?>

I need something like when click on update button so it can take the value and update the session array of particular product quantity Please help me out...

Answer 1

This is a pretty basic example, but you should make a function per action so you can more easily port the cart. Also, I am not sure why you have a $_GET in the switch and a $_POST in the case():

function AddToCart($default = 1)
    {
        // Set a default quantity (1). Check that the value is set and is number
        // Not sure why you are using a get for the code but not for these
        // attributes. Should it not be $_GET['quantity']??
        $qty                    =   (isset($_POST['quantity']) && is_numeric($_POST['quantity']))? $_POST['quantity']:$default;
        // Check that there is a valid numeric itemcode
        $item                   =   (isset($_POST['item_code']) && is_numeric($_POST['item_code']))? $_POST['item_code']:false;
        // If false, stop
        if(!$item)
            return;
        // Do your product query
        $productByCode          =   $db_handle->runQuery("SELECT * FROM menu WHERE item_code='" . $_GET["code"] . "'");
        // Assign the item code
        $itmcd                  =   $_GET["code"];
        $itemArray['code']      =   $itmcd;
        $itemArray['name']      =   $productByCode[0]["item_name"];
        $itemArray['price']     =   $productByCode[0]["item_price"];
        $itemArray['quantity']  =   (isset($_SESSION["cart_item"][$itmcd]))? $_SESSION["cart_item"][$itmcd]['quantity']+$qty : $qty;

        $_SESSION["cart_item"][$itmcd]  =   $itemArray;
    }

To use:

if(isset($_GET["action"]) && $_GET["action"] == 'add'))
    AddToCart();