Add-cart.php Num Work -

array. This is common for lightweight sites because it doesn't require constant database writes as the user browses. Database-Driven Storage:

"Infinite stock," Elias whispered, his fingers flying across the mechanical keyboard. If someone could "add" negative items, they weren't buying; they were injecting inventory into the system—or worse, triggering a refund for an item they never owned. add-cart.php num

fetch('add-cart.php', method: 'POST', headers: 'Content-Type': 'application/x-www-form-urlencoded', body: `product_id=123&num=$quantity` ) If someone could "add" negative items, they weren't

// (Optional) Check if user is logged in. // If not, you might use $_SESSION['cart'] for guest users. // For this article, we assume a logged-in user. $user_id = $_SESSION['user_id']; // For this article, we assume a logged-in user

| Test Case | Expected Behavior | Your Result | |-----------|------------------|--------------| | num=abc | 400 Bad Request / No change to cart | | | num=-5 | Ignored or default to 1 | | | num=1.5 | Reject as invalid integer | | | num=9999999 | Reject (max allowed quantity) | | | num=1%20OR%201=1 | No SQL error, no data leak | | | No num parameter | 400 Bad Request | | | Repeated requests to same num | Throttled after X requests/second | | | CSRF token missing | Cart not modified | |