Building a Shopping Cart

In Chapter 4 , you learned how to use CodeIgniter ’ s MVC framework to create a basic eCommerce

site, with its home page, category views, and product detail pages. In this chapter, you ’ ll learn how

to create the Shopping Cart. You ’ ll also get feedback from the client on how to polish the site and

then implement those changes inside your CSS and PHP files.

Displaying the Shopping Cart

At some point in any eCommerce site, site visitors add products to their shopping carts and then

try to check out. By the end of the chapter, you ’ ll have a working shopping cart (but no checkout

function, as you ’ ll need to confer with the client about this).

The approach you ’ re going to take with Claudia ’ s Kids is a simple, straightforward approach that

makes use of both CodeIgniter ’ s session object and native PHP sessions. If you ’ re used to working

with PHP sessions, you might be tempted to think that CodeIgniter ’ s session object is the same

thing. CodeIgniter sessions are different from PHP sessions, acting just like cookies. They can be

encrypted and can store serialized data that are automatically created or updated as needed.

To use CodeIgniter sessions, all you need to do is load the library. In this case, you ’ ve already

loaded the Session library in the autoloader.php file (in Chapter 2 ), so all you have to do now is

use the appropriate functions.

Because CodeIgniter sessions are cookies, you have the same limitations as you do with cookies

in general. For example, cookies can be tampered with by the end - user. This makes CodeIgniter

sessions (even if the data in them are encrypted) hard to trust. Another limitation is the fact that

a session cookie only holds 4 KB (kilobytes) of data. It is possible for someone to fill up their

session cookie either accidentally or with malicious intent.