Implement database-level transactions or locks when the checkout process begins to prevent double-selling stock to concurrent users.
// Stock Check (High Quality Feature) $currentQtyInCart = isset($_SESSION['cart'][$product_id]) ? $_SESSION['cart'][$product_id]['quantity'] : 0; if (($currentQtyInCart + $quantity) > $product['stock']) return ['status' => 'error', 'message' => 'Not enough stock available.'];
<?php // Secure session configuration ini_set('session.cookie_httponly', 1); ini_set('session.use_strict_mode', 1); ini_set('session.cookie_secure', 1); // HTTPS only addcartphp num high quality
Uses filter_input to force strict integer typing on product IDs and quantities.
// --- DATABASE LOOKUP (Prepared Statement) --- $pdo = getDbConnection(); $stmt = $pdo->prepare("SELECT id, name, price, stock_quantity FROM products WHERE id = ? AND status = 1"); $stmt->execute([$product_id]); $product = $stmt->fetch(PDO::FETCH_ASSOC); // --- DATABASE LOOKUP (Prepared Statement) --- $pdo
CREATE TABLE products ( id INT AUTO_INCREMENT PRIMARY KEY, name VARCHAR(255) NOT NULL, price DECIMAL(10,2) NOT NULL );
Uses session_start() to track the user's cart across different pages without requiring a database write for every click. // Backend response header('Content-Type: application/json')
– For cart displays that are accessed frequently, implement caching for the product data used in cart calculations.
// Backend response header('Content-Type: application/json'); echo json_encode([ 'success' => true, 'cart_count' => count($_SESSION['cart']), 'message' => 'Item added to cart successfully' ]); exit;
Create a PHP script or function that handles adding items to the cart. This example assumes you have a product ID and quantity to add.