Price: $49.99
// In add-cart.php if (!hash_equals($_SESSION['csrf_token'], $_POST['csrf_token'])) die('CSRF attack detected');
// Expected format: "123:2" $num = $_GET['num'] ?? ''; if (!preg_match('/^(\d+):(\d+)$/', $num, $matches)) die('Invalid format. Use ID:QTY'); add-cart.php num
Instead of globally reading raw variables like $_POST['num'] , this file uses PHP's native filter_input function with FILTER_VALIDATE_INT . This immediately drops any malicious inputs, alpha characters, or float symbols, returning a clean boolean false if verification fails. Defending Against SQL Injection with Prepared Statements
Never trust user input. We must ensure that the incoming product ID and the requested quantity ( ) are valid integers. Shopping Cart using PHP and MySQL #php Price: $49
If the num variable represents a product ID and is concatenated directly into a database query string, an attacker can append malicious payloads. This exploit lets attackers bypass authentication mechanisms or leak the entire customer database.
The component refers to a parameter (often passed via $_GET or $_POST ) that dictates the number of items to add. URL Example: add-cart.php?id=101&num=3 Action: Adds 3 units of Product ID 101 to the cart. 1. Frontend: Creating the Dynamic Input Shopping Cart using PHP and MySQL #php If
To support this frontend functionality, the PHP script must be modified to return a JSON response instead of a header redirection:
// Add to cart logic if (isset($_SESSION['cart'][$product_id])) // Product exists, update quantity $_SESSION['cart'][$product_id] += $quantity; else // New product, add to cart $_SESSION['cart'][$product_id] = $quantity;
// basic validation if ($product_id <= 0 || $num <= 0) http_response_code(400); echo json_encode(['error' => 'Invalid input']); exit;