Shopping Cart Class [probleem: product toevoegen en Cart laten zien]

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Ryan L

Ryan L

18/05/2011 21:19:02
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Hallo,

ik heb deze Shopping Cart Class gevonden maar nou lukt het me niet om een product page te maken waar je op "add to cart" kan klikken waarna een _POST gestuurd wordt naar dezelfde product page en dmv een if statement de method cart_add_item() wordt geroepen.

ik krijg de volgende foutmelding waneer ik naar de product page ga:
Warning: mysql_fetch_assoc() expects parameter 1 to be resource, boolean given in ../public/cart.php on line 261

Warning: mysql_fetch_assoc() expects parameter 1 to be resource, boolean given in ../public/cart.php on line 261

En wanneer ik op add to cart klik:

Fatal error: Cannot use object of type cart as array in ..public/cart.php on line 108

Kan iemand mij uitleggen wat er verkeerd is en hoe ik dit kan oplossen?
alvast bedankt.

dit is de class die ik gebruik
Quote:
Code (php)
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<?php
/**
* Shopping Cart Class
*
* @author Ben Barnett <[email protected]>
*/
    
    
/**
* Shopping Cart Class
*
* This module is a shopping cart class with add/edit/delete product functionality.
* Each item is stored in a session variable as an array with the productID being the key
* and the quantitly of the item as the value. The cookie stores the serialized cart contents
* between visits.
* IMPORTANT NOTE: The show_cart function
* outputs a very bland table so you will need to edit this to beautify it.

*/
class cart
{
    
    /**
    * The expiry time for the cart cookie
    */
    var $expire = 3600;
    
    
    var $del_cookie = -1;
    
    /**
    * Class constructor
    *
    * Start the session, if the cart doesn't exist as a session variable, check for a cookie,
    * if the cookie isn't there, make a new cart.
    */
    function cart()
    {
    // Start the session.
    //session_start();
    
    $time = time();
    $this->expire = $time + $this->expire;
    
    // If the session variables haven't been registered yet, do that now.
    if(!isset($_SESSION['cart']))
        {
        
        if(isset($_COOKIE['cart']))
            {
            $_SESSION['cart'] = array();
            $_SESSION['cart'] = unserialize(stripslashes($_COOKIE['cart']));
            $_SESSION['total_items'] = $this->cart_calculate_items($_SESSION['cart']);
            $_SESSION['total_price'] = $this->cart_calculate_price($_SESSION['cart']);
            }
        else
            {
            $_SESSION['cart'] = array();
            $_SESSION['total_items'] = 0;
            $_SESSION['total_price'] = 0.00;
            
            $s_cart = serialize($_SESSION['cart']);
            setcookie('cart', $s_cart, $this->expire);
            }
        }
    

    }
    
    
    
    /**
    * Displays the cart
    *
    * @param array $cart The cart you want to display.
    * @param boolean $pictures Show pictures in cart? (default=false)
    * @param boolean $editable Is cart editable? (default=true)
    */
    function cart_show($cart, $pictures = 'false', $editable = 'true')
    {
//    require($_SERVER['DOCUMENT_ROOT'].'/path/to/database/connection_code.php');
//    mysql_select_db($database_connAT, $connAT);
    echo "<table border=\"1\"><tr><td>Product</td><td>Quantity</td><td>Price</td></tr>\n";
    foreach($cart as $productID => $qty)
        {
        $product = $this->cart_get_item_details($productID);
        echo "<tr>\n";
        echo "<td>".$product['details']."</td><td>".$qty."</td><td>&pound;".$product['price']."</td>\n";
        echo "</tr>\n";
        }
    echo '</table>';
    }

    
    
    /**
    * Adds an item to the cart.
    *
    * If the item is already in the cart, it increments the quantity by one.
    * Otherwise, it adds one of the selected item to the cart. It then recalculates
    * the number of items in the cart and the total cost.
    *
    * @param string $item The productID to be added.
    */
    function cart_add_item($item)
    {
    // If cart item exists, increment it by one...
    if(isset($_SESSION['cart'][$item]))
        {
        $_SESSION['cart'][$item]++;
        
        }
        
    // ...otherwise add it as a new item.
    else
        {
        $_SESSION['cart'][$item] = 1;
        }
    
    // Recalculate totals
    $_SESSION['total_items'] = $this->cart_calculate_items($_SESSION['cart']);
    $_SESSION['total_price'] = $this->cart_calculate_price($_SESSION['cart']);
    $s_cart = serialize($_SESSION['cart']);
    setcookie('cart', $s_cart, $this->expire);
    }

    
    
    /**
    * Removes a product from the cart.
    *
    * Removes a product totally from the cart by unsetting it's key and value
    * from the session array.
    */
    function cart_delete_item($productID)
    {
    // Unset product variable
    unset($_SESSION['cart'][$productID]);
    
    // Recalculate totals
    $_SESSION['total_items'] = $this->cart_calculate_items($_SESSION['cart']);
    $_SESSION['total_price'] = $this->cart_calculate_price($_SESSION['cart']);
    $s_cart = serialize($_SESSION['cart']);
    setcookie('cart', $s_cart, $this->expire);
    }

    
    /**
    * Edits the number of each item in the cart
    *
    * If the number is set to zero, remove the item by unsetting the session variable. If
    * the number is anything else, set it the that number.
    *
    * @todo I'm not sure if this function needs any parameters passed to it to work
    * so if it doesn't, this could be why.
    */
    function cart_edit_item()
    {
    // Make sure the variables are being POSTed
    if(isset($_POST['update']))
        {
        foreach($_SESSION['cart'] as $productID => $qty)
            {
            if($_POST['$productID'] ==  0)
                {
                unset($_SESSION['cart'][$productID]);
                }
            else
                {
                $_SESSION['cart'][$productID] = $_POST['productID'];
                }
            }
        }
    // Recalculate totals
    $_SESSION['total_items'] = $this->cart_calculate_items($_SESSION['cart']);
    $_SESSION['total_price'] = $this->cart_calculate_price($_SESSION['cart']);
    $s_cart = serialize($_SESSION['cart']);
    setcookie('cart', $s_cart, $this->expire);
    }
    
    
    
    /**
    * Calculates the number of items in the cart.
    *
    * Calculates the number of items in the cart by looping through the cart incrementing
    * the number of items for each product.
    *
    * @param array $cart The cart to count items in.
    * @return integer The number of items in the cart.
    */
    function cart_calculate_items($cart)
    {
    // Initialise variable to default value
    $items = 0;
    
    // Make sure the cart is actully an array!
    if(is_array($cart))
        {
        // Loop through the cart and add the quanity of each item the the total
        foreach($_SESSION['cart'] as $productID => $qty)
            {
            $items += $qty;
            }
        }
    // Return the total number of items
    return $items;
    }
    
    
    
    /**
    * Calculates the total price of the cart contents.
    *
    * This function is one of the slowest in this application
    * as it has a long database query to carry out and total up.
    *
    * @param array $cart The cart to total the price in.
    * @return float The total price of cart contents.
    */
    function cart_calculate_price($cart)
    {
    // Initialise variable to default value
    $price = 0.00;
    
    // Make sure the cart is actully an array!
    if(is_array($cart))
        {
        
        /**
        * Require the database connection for finding prices.
        */
//        require($_SERVER['DOCUMENT_ROOT'].'/path/to/database/connection_code.php');
//        mysql_select_db($database_connAT, $connAT);
        
        // Loop through the cart array matching prices to products
        foreach($cart as $productID => $qty)
            {
            $query = "SELECT price FROM products WHERE id='$productID'";
            $result = mysql_query($query);
            
            // Then adding the (item price * quantity) to the total price
            //  and starting the loop again
            if($result)
                {
                $row_result = mysql_fetch_assoc($result);
                $item_price = $row_result['price'];
                $price += $item_price*$qty;
                }
            }
        }
    // Return the total price
    return $price;
    }
    
    
    function cart_get_item_details($productID)
        {
        $query = "SELECT * FROM products WHERE id='$productID'";
        $result = mysql_query($query);
        $row_result = mysql_fetch_assoc($result);
        return $row_result;
        }
    
}
?>


Dit is de product page:
Quote:
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<?php require_once("cart.php") ?>

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<?php
session_start();      // start the session


$cart =& $_SESSION['cart']; // point $cart to session cart.
if(!is_object($cart)) $cart = new Cart(); // if $cart ( $_SESSION['cart'] ) isn't an object, make a new cart

// end of header stuff

// Usually you would get your products from a database but we'll pretend..

$products = array();
$products[1] = array("id"=>1,"name"=>"A Bar of Soap","price"=>2.00);
$products[2] = array("id"=>2,"name"=>"Shampoo","price"=>4.80);
$products[3] = array("id"=>3,"name"=>"Pizza","price"=>12.95);


// check to see if any items are being added
if(isset($_POST['add'])) {
    $product = $_POST['id'];
    $cart->cart_add_item($product['id']);
}


// add product
echo "<table>";
foreach($products as $product) {
    echo "<tr><td><form method='post' action='demo.php'>";
    echo "<input type='hidden' name='id' value='".$product['id']."'/>";
    echo "".$product['name'].' $'.number_format($product['price'],2)." ";
    echo "<input type='text' name='qty' size='5' value='1'><input type='submit' value='Add to cart' name='add'>";
    echo "</form></td></tr>";
}
echo "</table>";


echo "<h2>Items in cart</h2>";

$cart->cart_show($cart);

?>
 
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