Update shipping price after picked price (PHP) - php

Question

I am working on a shopping cart for my site. In the cart area I pull shipping details from the db, including the price depending on zip code. When the user clicks "update cart".
I am trying to update the total with the shipping price. If anyone can point me in the right direction of figuring this out.
This is my function to display the cart.
function showCart() {
$cart = $_SESSION['cart'];
$zip = $_SESSION['zipcode'];
if ($cart) {
$items = explode(',',$cart);
$contents = array();
foreach ($items as $item) {
$contents[$item] = (isset($contents[$item])) ? $contents[$item] + 1 : 1;
}
$output[] = '<form action="cart.php?action=update" method="post" id="cart">';
$output[] = '<table>';
foreach ($contents as $id=>$qty) {
$sql = 'SELECT * FROM products WHERE id = '.$id;
$result = mysql_query($sql) or die(mysql_error());
$row = mysql_fetch_array($result, MYSQL_ASSOC);
extract($row);
$output[] = '<tr>';
$output[] = '<td>Remove</td>';
$output[] = '<td>'.$title.' by '.$author.'</td>';
$output[] = '<td>$'.$price.'</td>';
$output[] = '<td><input type="text" name="qty'.$id.'" value="'.$qty.'" size="3" maxlength="3" /></td>';
$output[] = '<td>$'.($price * $qty).'</td>';
$total += $price * $qty;
$output[] = '</tr>';
}
$output[] = '</table>';
$sql = 'SELECT * FROM zipcodes WHERE zipcode = '.$zip;
$result = mysql_query($sql) or die(mysql_error());
while($row = mysql_fetch_array($result, MYSQL_ASSOC)){
$output[] = '<label>Price: </label><select name="delivery" id="delivery" class="long-field">';
$output[] = '<option value="">Please Select</option>';
$output[] = '<option value='.$row['free_dev'].'>$'.$row['free_dev'].'</option>';
$output[] = '<option value='.$row['next_day_dev'].'>$'.$row['next_day_dev'].'</option>';
$output[] = '</select>';
}
$output[] = '<p>Delivery Charge: <strong>$'.$delivery.'</strong></p>';
$output[] = '<p>Grand total: <strong>$'.$total.'</strong></p>';
$output[] = '<div><button type="submit">Update cart</button></div>';
$output[] = '</form>';
} else {
$output[] = '<p>You shopping cart is empty.</p>';
}
return join('',$output);
}
And this the update part via cart.php
case 'update':
if ($cart) {
$newcart = '';
foreach ($_POST as $key=>$value) {
if (stristr($key,'qty')) {
$id = str_replace('qty','',$key);
$items = ($newcart != '') ? explode(',',$newcart) : explode(',',$cart);
$newcart = '';
foreach ($items as $item) {
if ($id != $item) {
if ($newcart != '') {
$newcart .= ','.$item;
} else {
$newcart = $item;
}
}
}
for ($i=1;$i<=$value;$i++) {
if ($newcart != '') {
$newcart .= ','.$id;
} else {
$newcart = $id;
}
}
}
}
}
$cart = $newcart;
break;
Thank you. Any help is greatly appreciated!
PS i am using the tutorial for the cart from here http://v3.thewatchmakerproject.com/journal/276/

Answer 1

Given that the code you provide is fairly agnostic to this problem, it's unclear where you're running into a wall. But to get you started:
case 'update':
if ($cart) {
$newcart = '';
foreach ($_POST as $key=>$value) {
... //same thing as before
}
$newcart .= $shipping_price; //or however you're encoding this. It's unclear.
}
$cart = $newcart;
break;
And also replace:
$output[] = '<p>Grand total: <strong>$'.$total.'</strong></p>';
with:
$output[] = '<p>Grand total: <strong>$'.$total+ $shipping_price.'</strong></p>';

Answer 2

If I were you I would search for a PHP Class shopping cart, that code reminds me of some PHP4 (and it should since the example is from 2005).
I didn't find a good link for an example, I'll try to describe the idea bellow.
You create two classes one represents the item the other the shopping cart ( the first can be just a result from a DB with mysql_fetch_object or something like Pdo it will turn it into a stdClass from php
class someItem
{
public $id;
public $qty;
public $price;
public $totalprice;
public function __get($var)
{
if ($var == 'totalPrice') {
return $this->price*$this->qty;
}
return $this->$var;
}
}
class ShoppingCart
{
private $items;
public function addItem($someItem)
{
if (array_key_exists($someItem->id, $this->items)) {
$this->items[$someItem->id]->qty = $this->items[$someItem->id]->qty + $someItem->qty;
} else {
$this->items[$someItem->id] = $someItem;
}
}
public function removeItem($someItem)
{
unset($this->items[$someItem->id]);
}
public function getTotal()
{
$total = 0;
foreach($this->items as $item){
$total += $item->totalPrice;
}
return $total;
}
}
serialize the info into the session
$_SESSION['user']['cart'] = serialize($Shoppingcart);
set a new shopping cart when user logs in clean it when he logs out.
Adding and removing the items can be done before everything
// whatever operation you whant and deal according to your HTML Form
foreach ($_POST['cart'] as $itemId ) {
$ItemObj = $db->getitemAsObject($itemId); // Use PDO or something
$shoppingcart->addItem($itemObj);
}
Resave the shopping cart to session after post
$_SESSION['user']['cart'] = serialize($Shoppingcart);