Add-cart.php Num ✮ < RECENT >
// Validate quantity if ($quantity <= 0) $quantity = 1;
By following the guidelines in this article:
An attacker could visit add-cart.php?num=105 UNION SELECT 1, database(), user(), 4... . This allows them to bypass authentication, exfiltrate database schemas, or dump sensitive user data. add-cart.php num
When a user clicks "Add to Cart" on a product gallery page, the browser transmits data to the server using either an HTTP POST or GET request. The handler script ( add-cart.php ) typically checks for two essential variable inputs:
connect_error) die("Connection failed: " . $conn->connect_error); // 2. Only allow POST requests for state changes if ($_SERVER['REQUEST_METHOD'] === 'POST') // 3. Validate and sanitize the 'num' input (Ensure it is a strict integer) if (isset($_POST['num']) && filter_var($_POST['num'], FILTER_VALIDATE_INT)) $product_id = (int)$_POST['num']; $quantity = isset($_POST['qty']) && filter_var($_POST['qty'], FILTER_VALIDATE_INT) ? (int)$_POST['qty'] : 1; if ($quantity <= 0) $quantity = 1; // 4. Use a Prepared Statement to fetch product verification from the database $stmt = $conn->prepare("SELECT id, name, price FROM products WHERE id = ?"); $stmt->bind_param("i", $product_id); $stmt->execute(); $result = $stmt->get_result(); if ($result->num_rows > 0) $product = $result->fetch_assoc(); // Initialize the cart session array if it doesn't exist if (!isset($_SESSION['cart'])) $_SESSION['cart'] = []; // 5. Update or Add the item to the session cart if (isset($_SESSION['cart'][$product_id])) $_SESSION['cart'][$product_id]['quantity'] += $quantity; else $_SESSION['cart'][$product_id] = [ 'name' => $product['name'], 'price' => $product['price'], // Price sourced safely from DB, not user input 'quantity' => $quantity ]; // Redirect back to the cart or shop page with a success message header("Location: cart.php?status=success"); exit(); else // Product ID not found in database header("Location: index.php?error=invalid_product"); exit(); $stmt->close(); else // Invalid 'num' parameter format header("Location: index.php?error=bad_input"); exit(); else // Reject GET requests to prevent CSRF and accidental crawler triggers header("HTTP/1.1 405 Method Not Allowed"); echo "Method Not Allowed. Use POST."; $conn->close(); ?> Use code with caution. Key Best Practices Implemented Above // Validate quantity if ($quantity <= 0) $quantity
In the fast-paced world of e-commerce, the ability for a customer to quickly and accurately add products to a shopping cart is fundamental. Whether you are building a custom PHP e-commerce site or managing a platform that uses traditional scripting, understanding the mechanics behind —the process of adding items while specifying a numerical quantity—is crucial for conversion rates and user experience.
If the add-cart.php file does not properly sanitize the num input, an attacker could change the URL to: add-cart.php?num=123 OR 1=1 If the backend code directly inserts this into a query like SELECT * FROM products WHERE id = $num , it can allow unauthorized database access. 2. Insecure Direct Object Reference (IDOR) When a user clicks "Add to Cart" on
header('Location: products.php?error=invalid_product'); exit;
