Simple shopping cart

m_tyhurst2002 · June 21, 2013

Hello, first off, I don't have a lot of programming experience. I am working off a YouTube tutorial...

I am working with a simple PHP/MYSQL shopping cart that only supports one category and a Paypal checkout/add to cart button. My index.php page successfully shows the items that are in the database with the products() function. I have another function that shows the carts contents, cart(). That successfully displays the carts contents, if available.

What I am trying to do is create another function cart_qty() to break apart the contents of cart() to see how many items there are. I would like to display, "You have 1 item" or "...2 items", ect.

Any thoughts or helpful direction would be awesome!

index.php

<?php

require 'cart.php';

?>
<!DOCTYPE html>
<head>
</head>
<body>
	<div class="container"><!-- start container -->
		<div class="sixteen columns">
			<h1 class="remove-bottom" style="margin-top: 40px">Test Shpping Cart </h1>
			<hr />
		</div>
        <div id="products" class="two-thirds column">
            <h1>Products In Our Store</h1>
            <?php
            echo products();
            ?>
        </div>
        <div id="shoppingcart" class="one-third column">
            <h3>Your Cart</h3>
            <?php
            echo cart();
            ?>
        <br>
        <br>
        <br>
            <?php
            echo cart_qty();
            ?>
        </div>
	</div><!-- end container -->
</body>
</html>

cart.php

<?php


	// Start the session
	session_start();
	//session_destroy();
	//error_reporting(0);
	
	$page = 'index.php';
	
	mysql_connect('localhost', 'root', '') or die(mysql_error());
	mysql_select_db('cart') or die(mysql_error());
	
	
	// add item to cart
	if (isset($_GET['add'])) {
		$quantity = mysql_query('SELECT id, quantity FROM tblProducts WHERE id=' . mysql_real_escape_string((int)$_GET['add']));  //prevents SQL injections
		while($quantity_row = mysql_fetch_assoc($quantity)) {
			if($quantity_row['quantity'] != $_SESSION['cart_' . (int)$_GET['add']]) {
				$_SESSION['cart_' . (int)$_GET['add']] += '1';
			}
		}
		header('Location: ' . $page);
	}
	
	
	// remove one item from cart
	if (isset($_GET['remove'])) {
		$_SESSION['cart_' . (int)$_GET['remove']] --;
		header('Location: ' . $page);
	}
	
	
	// delete item item from cart
	if (isset($_GET['delete'])) {
		$_SESSION['cart_' . (int)$_GET['delete']] = '0';
		header('Location: ' . $page);
	}
	
	
	// display list of products
	function products() {
		$get = mysql_query('SELECT id, name, description, price, shipping FROM tblProducts WHERE quantity > 0 ORDER BY id ASC');
		
		if (mysql_num_rows($get) ==0) {
			echo 'There are no products to display!';
		} else {
			while($get_row = mysql_fetch_assoc($get)) {
				echo '<p>' . $get_row['name'] . '<br>' . $get_row['description'] . '<br>' . number_format($get_row['price'], 2) . '<br>' . $get_row['shipping'] . '<br><a href="cart.php?add=' . $get_row['id'] . '">Add</a></p>';
			}
		}
	}
	
	
	//generate inputs required by PayPal
	function paypal_items() {
		$num = 0;
		foreach($_SESSION as $name => $value) {
			if($value != 0) {
				if(substr($name, 0, 5) == 'cart_') {
					$id = substr($name, 5, strlen($name)-5);
					$get = mysql_query('SELECT id, name, price, shipping FROM tblProducts WHERE id=' . mysql_real_escape_string((int)$id));  //prevents SQL injections
					while($get_row = mysql_fetch_assoc($get)) {
						$num++;
						echo '<input type="hidden" name="item_number_' . $num . '" value="' . $id . '">';
						echo '<input type="hidden" name="item_name_' . $num . '" value="' . $get_row['name'] . '">';
						echo '<input type="hidden" name="amount_' . $num . '" value="' . $get_row['price'] . '">';
						echo '<input type="hidden" name="shipping_' . $num . '" value="' . $get_row['shipping'] . '">';
						echo '<input type="hidden" name="shipping2_' . $num . '" value="' . $get_row['shipping'] . '">';
						echo '<input type="hidden" name="quantity_' . $num . '" value="' . $value . '">';
					}
				}
			}
		}
	}
	
	//display how many items are in the cart
	function cart() {
		foreach($_SESSION as $name => $value) {
			if($value>0) {
				if(substr($name, 0, 5) == 'cart_') {
					
					//get exact number after "'cart_'$id"
					$id = substr($name, 5, (strlen($name)-5));
					//echo $id;
					
					$get = mysql_query('SELECT id, name, price FROM tblProducts WHERE id=' . mysql_real_escape_string((int)$id));  //prevents SQL injections
					while($get_row = mysql_fetch_assoc($get)) {
						$sub = $get_row['price'] * $value;
						echo $get_row['name'] . ' x ' . $value . ' @ $' . number_format($get_row['price'], 2) . ' = $' .  number_format($sub, 2) . '<a href="cart.php?remove=' . $id .'">-</a> <a href="cart.php?add=' . $id .'">+</a> <a href="cart.php?delete=' . $id .'">delete</a><br>';
					}
				}
				$total += number_format($sub, 2);
			} 
		}
		if ($total == 0) {
			echo "Your cart is empty.";
		} 
		else {
			echo 'Total: $' . number_format($total, 2) . '';
			?>
			<form target="paypal" action="https://www.paypal.com/cgi-bin/webscr" method="post">
				<input type="hidden" name="cmd" value="_cart">
				<input type="hidden" name="upload" value="1">
				<input type="hidden" name="business" value="someone@yahoo.com">
				<?php paypal_items(); ?>
				<input type="hidden" name="currency_code" value="USD">
				<input type="hidden" name="bn" value="PP-ShopCartBF:btn_cart_LG.gif:NonHosted">
				<input type="image" src="https://www.paypalobjects.com/en_US/i/btn/btn_cart_LG.gif" border="0" name="submit" alt="PayPal - The safer, easier way to pay online!">
	<img alt="" border="0" src="https://www.paypalobjects.com/en_US/i/scr/pixel.gif" width="1" height="1">
			</form>		
			<?php
		}
	}


	function cart_qty() {
		///how many items are in cart
	}
	
?>

mac_gyver · June 21, 2013

while this doesn't directly address your question, it will make the answer take just one line of code.

the definition of your $_SESSION based cart should be changed and simplified to directly support the operations you need to perform on the data.

using [cart_id] as the array index requires extra processing for every reference you make to the cart entries.

you need to use an array $_SESSION['cart'] that holds an entry for each id - $_SESSION['cart'][id] = qty;

to get a count of the different items (id's) in the cart, just use - count($_SESSION['cart'])

to get the quantity of all items in the cart, just use - array_sum($_SESSION['cart'])

by changing the cart definition to this, you will also simplify most of the code you currently have to just a line or two to manipulate any entry in the cart.

also, in your cart() function, you should not run a select query inside of a loop (due to the perform hit). you should get all the item id's at one time and run one query (using a WHERE id IN( ... ) statement) to get all the information about those items in one query. the cart definition i have suggested would let you do this easily as well using - array_keys($_SESSION['cart'])

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Simple shopping cart

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