AMP: Building Accelerated Mobile Pages

Building the shopping cart server

Now let's look at the server. When an item is added to the cart, we need to keep track of the total price, as well as the product ID, product name, and price for each product. Once again, the details of how to build an e-commerce backend don't really belong in a book about AMP, so we'll just describe it briefly here (and you can see the code at /ch6/add-to-cart.php, and /ch6/CartFileStorage.php).

On the server, we'll use a simple file-based system to store the carts. Each cart will be identified by the CLIENT_ID. When the add-to-cart form is submitted to the server, the server should do the following:

1. Retrieve the cart from file storage by matching CLIENT_ID.
2. Add the new item to the cart, update the total ...