shopping cart refresh issue

gtseviper · September 7, 2012

I finished getting the shopping cart organize. Every time i refresh the page (under the shopping_cart.php) an addition quantity is added by increment of 1 (changing the final price as well). How do I stop this from happening?

shopping_cart.php

<?php
// Include functions
require_once('inc/functions.inc.php');

// Start the session
session_start();

// Process actions
$cart = $_SESSION['cart'];
$action = $_GET['action'];
switch ($action) {
case 'add':
	if ($cart) {
		$cart .= ','.$_GET['id'];
	} else {
		$cart = $_GET['id'];
	}
	break;		
case 'delete':
	if ($cart) {
		$items = explode(',',$cart);
		$newcart = '';
		foreach ($items as $item) {
			if ($_GET['id'] != $item) {
				if ($newcart != '') {
					$newcart .= ','.$item;
				} else {
					$newcart = $item;
				}
			}
		}
		$cart = $newcart;
	}
	break;
case 'update':
if ($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;
}
$_SESSION['cart'] = $cart;
?>

functions.inc.php

<?php
function writeShoppingCart() {
$cart = $_SESSION['cart'];
if (!$cart) {
	return '<p>You have no items in your shopping cart</p>';
} else {
	// Parse the cart session variable
	$items = explode(',',$cart);
	$s = (count($items) > 1) ? 's':'';
	return '<p>Shopping Cart <a href="shopping_cart.php">'.count($items).' item'.$s.' </a></p>';
}
}

function showCart() {
global $db;
$cart = $_SESSION['cart'];
if ($cart) {
	$items = explode(',',$cart);
	$contents = array();
	foreach ($items as $item) {
		$contents[$item] = (isset($contents[$item])) ? $contents[$item] + 1 : 1;
	}

	$output[] = '<form action="shopping_cart.php?action=update" method="post" id="cart">';
	$output[] = '<table border="0" width="100%" cellspacing="0" cellpadding="0">';
	foreach ($contents as $id=>$qty) {
		$sql = 'SELECT * FROM Products WHERE id = '.$id;
		$result = $db->query($sql);
		$row = $result->fetch();
		extract($row);

        $output[] = '<tr>';        
            	$output[] = '<td width="217" align="center">
					<a class="right_20" href="product_info.php?products_id='.$id.'">
					<img src="images/product_5.jpg" alt="Consectetur adipiscing" title="Consectetur adipiscing" 
					width="211" height="211" /></a></td>';
			$total += $price * $qty;		
			$output[] = '<td width="414" valign="top"><a href="product_info.php?products_id='.$id.'">
					<strong>Consectetur adipiscing</strong></a>
    					<span class="markProductOutOfStock">***</span><br /><br />
					<input type="text" name="qty'.$id.'" value="'.$qty.'" size="3" maxlength="3" />
                    	<div><button type="submit">Update cart</button> or 
					<a href="shopping_cart.php?action=delete&id='.$id.'" class="r">Remove</a></div></td>';
			$output[] = '<td width="207" align="right" valign="top"> <strong>$'.($price * $qty).'</strong></td>';
	$output[] = '</tr>'; 


	}
	$output[] = '<tr>';	
			$output[] = '<td colspan="2"></td>';
			$output[] = '<td ><p align="right">Grand total: <strong>$'.$total.'</strong></p></td>';
	$output[] = '</tr>'; 
	$output[] = '<tr>';
			$output[] = '<td colspan="3"><p class="stockWarning" align="center">Products marked with *** dont 	
						exist in desired quantity in our stock.<br />You can buy them anyway and check the 
						quantity we have in stock for immediate deliver in the checkout process.</p></td>';
	$output[] = '</tr>';
	$output[] = '</table>';
	$output[] = '</form>';

} else {
	$output[] = '<p><a href="products_new.php">Continue Shopping</a></p>';
}
return join('',$output);

}
?>

MMDE · September 7, 2012

I finished getting the shopping cart organize. Every time i refresh the page (under the shopping_cart.php) an addition quantity is added by increment of 1 (changing the final price as well). How do I stop this from happening?

shopping_cart.php

<?php
// Include functions
require_once('inc/functions.inc.php');

// Start the session
session_start();

// Process actions
$cart = $_SESSION['cart'];
$action = $_GET['action'];
switch ($action) {
case 'add':
	if ($cart) {
		$cart .= ','.$_GET['id'];
	} else {
		$cart = $_GET['id'];
	}
	break;		
case 'delete':
	if ($cart) {
		$items = explode(',',$cart);
		$newcart = '';
		foreach ($items as $item) {
			if ($_GET['id'] != $item) {
				if ($newcart != '') {
					$newcart .= ','.$item;
				} else {
					$newcart = $item;
				}
			}
		}
		$cart = $newcart;
	}
	break;
case 'update':
if ($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;
}
$_SESSION['cart'] = $cart;
?>

functions.inc.php

<?php
function writeShoppingCart() {
$cart = $_SESSION['cart'];
if (!$cart) {
	return '<p>You have no items in your shopping cart</p>';
} else {
	// Parse the cart session variable
	$items = explode(',',$cart);
	$s = (count($items) > 1) ? 's':'';
	return '<p>Shopping Cart <a href="shopping_cart.php">'.count($items).' item'.$s.' </a></p>';
}
}

function showCart() {
global $db;
$cart = $_SESSION['cart'];
if ($cart) {
	$items = explode(',',$cart);
	$contents = array();
	foreach ($items as $item) {
		$contents[$item] = (isset($contents[$item])) ? $contents[$item] + 1 : 1;
	}

	$output[] = '<form action="shopping_cart.php?action=update" method="post" id="cart">';
	$output[] = '<table border="0" width="100%" cellspacing="0" cellpadding="0">';
	foreach ($contents as $id=>$qty) {
		$sql = 'SELECT * FROM Products WHERE id = '.$id;
		$result = $db->query($sql);
		$row = $result->fetch();
		extract($row);

        $output[] = '<tr>';        
            	$output[] = '<td width="217" align="center">
					<a class="right_20" href="product_info.php?products_id='.$id.'">
					<img src="images/product_5.jpg" alt="Consectetur adipiscing" title="Consectetur adipiscing" 
					width="211" height="211" /></a></td>';
			$total += $price * $qty;		
			$output[] = '<td width="414" valign="top"><a href="product_info.php?products_id='.$id.'">
					<strong>Consectetur adipiscing</strong></a>
    					<span class="markProductOutOfStock">***</span><br /><br />
					<input type="text" name="qty'.$id.'" value="'.$qty.'" size="3" maxlength="3" />
                    	<div><button type="submit">Update cart</button> or 
					<a href="shopping_cart.php?action=delete&id='.$id.'" class="r">Remove</a></div></td>';
			$output[] = '<td width="207" align="right" valign="top"> <strong>$'.($price * $qty).'</strong></td>';
	$output[] = '</tr>'; 


	}
	$output[] = '<tr>';	
			$output[] = '<td colspan="2"></td>';
			$output[] = '<td ><p align="right">Grand total: <strong>$'.$total.'</strong></p></td>';
	$output[] = '</tr>'; 
	$output[] = '<tr>';
			$output[] = '<td colspan="3"><p class="stockWarning" align="center">Products marked with *** dont 	
						exist in desired quantity in our stock.<br />You can buy them anyway and check the 
						quantity we have in stock for immediate deliver in the checkout process.</p></td>';
	$output[] = '</tr>';
	$output[] = '</table>';
	$output[] = '</form>';

} else {
	$output[] = '<p><a href="products_new.php">Continue Shopping</a></p>';
}
return join('',$output);

}
?>

First of all...

$cart = $_SESSION['cart'];

You must check if the variables you use are set. isset()

Don't assume they exist when you haven't just set them yourself.

		foreach ($_POST as $key=>$value) {
		if (stristr($key,'qty')) {

Why do you need to do stristr through all $_POST data?

Can't they all the products be put in it's own array when sent as $_POST data, so you can foreach those.

The name in the form inputs: "product[id][name]" and "product[id][quantity]"

I can't see when you use those two included functions.

MMDE · September 7, 2012

		foreach ($_POST as $key=>$value) {
		if (stristr($key,'qty')) {
			$id = str_replace('qty','',$key);
			$items = ($newcart != '') ? explode(',',$newcart) : explode(',',$cart);

What does variables in $_POST that contains the 'qty' in their keyname contain? Just a little confused about it, as I would think it contained how many there is of a product they want to update.

		foreach ($contents as $id=>$qty) {
		$sql = 'SELECT * FROM Products WHERE id = '.$id;

Security hole, because the $id is provided by the client.

Another thing I don't get is why you keep writing arrays to string and then back to arrays and then to string and then array etc >_> So hard to read and so unnecessary.

Here's your problem:

				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;
				}
			}

More precisely here:

for ($i=1;$i<=$value;$i++) {

change it to:

for ($i=1;$i<$value;$i++) {

PFMaBiSmAd · September 7, 2012

To prevent a page refresh from repeating the last action, you will need to redirect to the same page with the ?action=xxxxxx get parameter removed from the URL.

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shopping cart refresh issue

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