Addcartphp Num High Quality

Check real‑time inventory to avoid overselling:

Implement database-level transactions or locks when the checkout process begins to prevent double-selling stock to concurrent users.

// Escape output when displaying echo htmlspecialchars($product['name'], ENT_QUOTES, 'UTF-8'); ?> addcartphp num high quality

Write robust tests for your ShoppingCart class checking behaviors such as adding negative quantities, handling zero-stock items, and boundaries for extreme integers.

// Remove if quantity is zero or negative if ($newQuantity <= 0) unset($_SESSION['cart'][$cartKey]); return ['success' => true, 'removed' => true]; CREATE TABLE products ( id INT AUTO_INCREMENT PRIMARY

$this->expectException(InvalidArgumentException::class); $this->cart->addItem(1, -5, ['name' => 'Test', 'price' => 10]);

Before writing a single line of PHP, let’s define what a robust “add to cart” flow looks like: Sanitize and Validate Input Parameters (ID and Num)

: Enforce strict type declarations ( declare(strict_types=1); ) if this script forms part of a larger object-oriented class system.

CREATE TABLE products ( id INT AUTO_INCREMENT PRIMARY KEY, name VARCHAR(255) NOT NULL, price DECIMAL(10,2) NOT NULL );

PDO::ERRMODE_EXCEPTION, PDO::ATTR_DEFAULT_FETCH_MODE => PDO::FETCH_ASSOC, PDO::ATTR_EMULATE_PREPARES => false, ]); catch (PDOException $e) echo json_encode(['success' => false, 'message' => 'Database connection failed.']); exit; // 2. Validate Request Method if ($_SERVER['REQUEST_METHOD'] !== 'POST') http_response_code(405); echo json_encode(['success' => false, 'message' => 'Method Not Allowed. Use POST.']); exit; // 3. Sanitize and Validate Input Parameters (ID and Num) $productId = filter_input(INPUT_POST, 'product_id', FILTER_VALIDATE_INT); $quantity = filter_input(INPUT_POST, 'num', FILTER_VALIDATE_INT); if ($productId === false || $productId === null || $quantity === false || $quantity === null) http_response_code(400); echo json_encode(['success' => false, 'message' => 'Invalid product ID or quantity format.']); exit; if ($quantity <= 0) http_response_code(400); echo json_encode(['success' => false, 'message' => 'Quantity must be greater than zero.']); exit; // 4. Verify Product Existence and Stock Levels $stmt = $pdo->prepare("SELECT id, name, price, stock FROM products WHERE id = :id LIMIT 1"); $stmt->execute(['id' => $productId]); $product = $stmt->fetch(); if (!$product) http_response_code(404); echo json_encode(['success' => false, 'message' => 'Product not found.']); exit; // Initialize the cart session structure if it doesn't exist if (!isset($_SESSION['cart'])) $_SESSION['cart'] = []; // Calculate target quantity if item already exists in cart $currentCartQty = isset($_SESSION['cart'][$productId]) ? $_SESSION['cart'][$productId]['num'] : 0; $targetQty = $currentCartQty + $quantity; // Inventory Check if ($targetQty > $product['stock']) http_response_code(400); echo json_encode([ 'success' => false, 'message' => "Cannot add requested quantity. Only $product['stock'] items available in stock." ]); exit; // 5. Update Cart State $_SESSION['cart'][$productId] = [ 'id' => (int)$product['id'], 'name' => $product['name'], 'price' => (float)$product['price'], 'num' => (int)$targetQty ]; // Calculate total cart items for UI updates $totalItems = 0; foreach ($_SESSION['cart'] as $item) $totalItems += $item['num']; // 6. Return High-Quality JSON Response echo json_encode([ 'success' => true, 'message' => 'Product added to cart successfully.', 'cart_count' => $totalItems, 'item' => $_SESSION['cart'][$productId] ]); Use code with caution. Deep Dive into High-Quality Optimization Techniques 1. Why FILTER_VALIDATE_INT Matters