// Optionally enforce precision $num = round($num, 2); // e.g., 1.25 kg Protect your server from rapid addcartphp spam:
Now we handle the num within the session cart. A high-quality cart supports quantity accumulation. addcartphp num high quality
// Assuming $pdo is your database connection $stmt = $pdo->prepare("SELECT id, name, price, stock_quantity FROM products WHERE id = ? AND status = 'active'"); $stmt->execute([$product_id]); $product = $stmt->fetch(PDO::FETCH_ASSOC); if (!$product) die(json_encode(['error' => 'Product not found'])); // Optionally enforce precision $num = round($num, 2); // e
// If product already in cart, update quantity (add to existing) if (isset($_SESSION['cart'][$product_id])) $new_quantity = $_SESSION['cart'][$product_id]['quantity'] + $num; Checking Inventory Before Adding A premium addcartphp script
// HIGH QUALITY: Maximum quantity limit (business rule) $MAX_QUANTITY = 99; if ($num > $MAX_QUANTITY) http_response_code(400); die(json_encode(['error' => "Maximum quantity per item is $MAX_QUANTITY"]));
// HIGH QUALITY: Strict numeric validation with reasonable defaults if ($num === false || $num === null) // Not a valid integer http_response_code(400); die(json_encode(['error' => 'Quantity (num) must be a valid integer']));
This uses FILTER_VALIDATE_INT (not intval() ), which distinguishes between 0 , null , and false . It rejects decimals, strings, and empty values explicitly. 2.2. Checking Inventory Before Adding A premium addcartphp script never assumes stock. It queries the database live.