Add-cart.php Num Jun 2026

If add-cart.php handles state-changing operations via GET requests, an attacker can trick a logged-in user into adding hundreds of items to their cart simply by embedding on an external malicious website. Building a Secure add-cart.php Script

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

// 5. Initialise the session cart array if needed if (!isset($_SESSION['cart'])) $_SESSION['cart'] = [];

In conclusion, scripts like "add-cart.php" are essential components of e-commerce websites. They not only enable the basic functionality of adding items to a shopping cart but also contribute to a seamless and engaging user experience. By efficiently managing product additions and quantities, these scripts help bridge the gap between product browsing and successful transactions.

0) // If cart doesn't exist, create it if (!isset($_SESSION['cart'])) $_SESSION['cart'] = []; // Add or update quantity if (isset($_SESSION['cart'][$product_id])) $_SESSION['cart'][$product_id] += $quantity; else $_SESSION['cart'][$product_id] = $quantity; // Redirect back to product page or cart header('Location: cart.php'); exit(); else echo "Invalid quantity."; ?> Use code with caution. Key Considerations for add-cart.php num 1. Input Validation and Security

Even with proper casting, the num parameter can break business rules.

The Zen Cart vulnerability (CVE‑2006‑4214) allowed remote attackers to execute arbitrary SQL commands by manipulating the quantity field in the add_cart function. An attacker could modify the session, extract user data, or even corrupt the entire database.

: Sends the user back to the product page or the cart view, often using a header redirect or a JSON response if using AJAX. Common Code Structure

This article explores how to build a secure and efficient add-cart.php script from scratch.

: While add-cart.php?id=...&num=... is simple, using POST is safer and cleaner, as it doesn't expose data in the URL.

A well‑written add-cart.php script handles three distinct scenarios:

// ... Logic continues below

if ($quantity > 100) // Set a reasonable max per transaction die("Quantity exceeds maximum allowed.");