$product_id = isset($_POST['product_id']) ? (int)$_POST['product_id'] : 0; $quantity = isset($_POST['num']) ? (int)$_POST['num'] : 1;
While add-cart.php?num= is a functional relic of the early web, its presence today is often a red flag for security vulnerabilities. Understanding how these scripts work is the first step toward building—or securing—a robust online marketplace. add-cart.php num
: Relying on client-side values for final price calculations rather than re-verifying against the database on the server. Recommended Best Practices $product_id = isset($_POST['product_id'])
The attacker uses Burp Suite to fuzz the num parameter with a payload list: 1 , 1.1 , -1 , 999999 , 1 UNION SELECT 1 , 1%00 . Understanding how these scripts work is the first
If you don't handle this correctly, your cart will simply overwrite the item instead of incrementing it, leading to a frustrating user experience. In this guide, we will break down how to create a robust add-cart.php
Before writing code, it is essential to understand what add-cart.php actually needs to do. It is not simply "saving an item." The script must: