PHP and SQL Shopping Cart is Not Adding Products to Shopping Cart

StackOverflow https://stackoverflow.com/questions/22152479

Question

I am trying to make a simple MSSQL and PHP shopping cart for my website. The page index.php correctly retrieves the products from my MSSQL products table and displays them. For each product displayed there is an Add to Cart button. The button should use $_SESSION to store the added product into the shopping cart via the cart_update.php page. The products added to the shopping cart should be displayed at the bottom of the index.php page. Currently, when the Add to Cart button is hit, no products are added to the shopping cart. I am unsure why this is happening.

Here is my index.php page code:

<?php
session_start();
include_once("config.php");
?>
<!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>Untitled Document</title>
</head>

<body>
<div class="products">
<?php
//current URL of the Page. cart_update.php redirects back to this URL
$current_url = base64_encode("http://".$_SERVER['HTTP_HOST'].$_SERVER['REQUEST_URI']);
    $query = "SELECT * FROM products ORDER BY id ASC";
    $results = mssql_query($query, $mysqli);
    if ($results) { 
        //output results from database
        while($obj = mssql_fetch_object($results))
        {

            echo '<div class="product">'; 
            echo '<form method="post" action="cart_update.php">';
            echo '<div class="product-thumb"><img src="images/'.$obj->product_img_name.'"></div>';
            echo '<div class="product-content"><h3>'.$obj->product_name.'</h3>';
            echo '<div class="product-desc">'.$obj->product_desc.'</div>';
            echo '<div class="product-info">Price '.$currency.$obj->price.' <button class="add_to_cart">Add To Cart</button></div>';
            echo '</div>';
            echo '<input type="hidden" name="product_code" value="'.$obj->product_code.'" />';
            echo '<input type="hidden" name="type" value="add" />';
            echo '<input type="hidden" name="return_url" value="'.$current_url.'" />';
            echo '</form>';
            echo '</div>';
        }

}
?>
</div>
<div class="shopping-cart">
<h2>Your Shopping Cart</h2>
<?php
if(isset($_SESSION["products"]))
{
    $total = 0;
    echo '<ol>';
    foreach ($_SESSION["products"] as $cart_itm)
    {
        echo '<li class="cart-itm">';
        echo '<span class="remove-itm"><a href="cart_update.php?removep='.$cart_itm["code"].'&return_url='.$current_url.'">&times;</a></span>';
        echo '<h3>'.$cart_itm["name"].'</h3>';
        echo '<div class="p-code">P code : '.$cart_itm["code"].'</div>';
        echo '<div class="p-qty">Qty : '.$cart_itm["qty"].'</div>';
        echo '<div class="p-price">Price :'.$currency.$cart_itm["price"].'</div>';
        echo '</li>';
        $subtotal = ($cart_itm["price"]*$cart_itm["qty"]);
        $total = ($total + $subtotal);
    }
    echo '</ol>';
    echo '<span class="check-out-txt"><strong>Total : '.$currency.$total.'</strong> <a href="view_cart.php">Check-out!</a></span>';
    echo '<span class="empty-cart"><a href="cart_update.php?emptycart=1&return_url='.$current_url.'">Empty Cart</a></span>';
}else{
    echo 'Your Cart is empty';
}
?>
</div>
</body>
</html>

And here is my cart_update.php page code:

<!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>Untitled Document</title>
</head>

<body>
<?php
session_start(); //start session
include_once("config.php"); //include config file

//empty cart by distroying current session
if(isset($_GET["emptycart"]) && $_GET["emptycart"]==1)
{
    $return_url = base64_decode($_GET["return_url"]); //return url
    session_destroy();
    header('Location:'.$return_url);
}

//add item in shopping cart
if(isset($_POST["type"]) && $_POST["type"]=='add')
{
    $product_code   = filter_var($_POST["product_code"], FILTER_SANITIZE_STRING); //product code
    $product_qty    = filter_var($_POST["product_qty"], FILTER_SANITIZE_NUMBER_INT); //product code
    $return_url     = base64_decode($_POST["return_url"]); //return url

    //limit quantity for single product
    if($product_qty > 10){
        die('<div align="center">This demo does not allowed more than 10 quantity!<br /><a href="http://sanwebe.com/assets/paypal-shopping-cart-integration/">Back To Products</a>.</div>');
    }
    $query = "SELECT product_name,price FROM products WHERE product_code='$product_code' LIMIT 1";
    //MySqli query - get details of item from db using product code
    $results = mssql_query($query, $mysqli);
    $obj = mssql_fetch_object($results);

    if ($results) { //we have the product info 

        //prepare array for the session variable
        $new_product = array(array('name'=>$obj->product_name, 'code'=>$product_code, 'qty'=>$product_qty, 'price'=>$obj->price));

        if(isset($_SESSION["products"])) //if we have the session
        {
            $found = false; //set found item to false

            foreach ($_SESSION["products"] as $cart_itm) //loop through session array
            {
                if($cart_itm["code"] == $product_code){ //the item exist in array

                    $product[] = array('name'=>$cart_itm["name"], 'code'=>$cart_itm["code"], 'qty'=>$product_qty, 'price'=>$cart_itm["price"]);
                    $found = true;
                }else{
                    //item doesn't exist in the list, just retrive old info and prepare array for session var
                    $product[] = array('name'=>$cart_itm["name"], 'code'=>$cart_itm["code"], 'qty'=>$cart_itm["qty"], 'price'=>$cart_itm["price"]);
                }
            }

            if($found == false) //we didn't find item in array
            {
                //add new user item in array
                $_SESSION["products"] = array_merge($product, $new_product);
            }else{
                //found user item in array list, and increased the quantity
                $_SESSION["products"] = $product;
            }

        }else{
            //create a new session var if does not exist
            $_SESSION["products"] = $new_product;
        }

    }

    //redirect back to original page
    header('Location:'.$return_url);
}

//remove item from shopping cart
if(isset($_GET["removep"]) && isset($_GET["return_url"]) && isset($_SESSION["products"]))
{
    $product_code   = $_GET["removep"]; //get the product code to remove
    $return_url     = base64_decode($_GET["return_url"]); //get return url


    foreach ($_SESSION["products"] as $cart_itm) //loop through session array var
    {
        if($cart_itm["code"]!=$product_code){ //item does,t exist in the list
            $product[] = array('name'=>$cart_itm["name"], 'code'=>$cart_itm["code"], 'qty'=>$cart_itm["qty"], 'price'=>$cart_itm["price"]);
        }

        //create a new product list for cart
        $_SESSION["products"] = $product;
    }

    //redirect back to original page
    header('Location:'.$return_url);
}
?>
</body>
</html>

Thank you for any help. All help is greatly appreciated.

Was it helpful?

Solution

To add products to the shopping cart I had to change the query in the cart_update.php page where 

$query = "SELECT product_name,price FROM products WHERE product_code='$product_code LIMIT 1'";

to 

$query = "SELECT TOP 1 product_name,price FROM products WHERE product_code='$product_code'";

This is because LIMIT does not work in SQL Server, and the equivalent is TOP.

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