Specifications

As with other places where we directly refer to $HTTP_POST_VARS, you need to have

track_vars enabled for this to work. We process the user’s card, and, if all is successful,

destroy her session.

The card processing function as we have written it simply returns true.

When you set up a live site, you will need to make a decision about what transaction clearing

mechanism you want to use. You can

• Sign up with a transaction clearing provider. There are many, many alternatives here

depending on the area you live in. Some of these will offer real-time clearing, and others

won’t. Whether you need live clearing depends on the service you are offering. If you are

providing a service online, you will most likely want it; if you are shipping goods, it’s

less crucial. Either way, these providers relieve you of the responsibility of storing credit

card numbers.

• Send a credit card number to yourself via encrypted email, for example, by using PGP or

GPG as covered in Chapter 15. When you receive and decrypt the email, you can process

these transactions manually.

• Store the credit card numbers in your database. We do not recommend this option unless

you really, seriously know what you’re doing with system security. You can read Chapter

15 for more details about why this is a bad idea.

That’s it for the shopping cart and payment modules.

Implementing an Administration Interface

The administration interface we have implemented is very simple. All we have done is build a

Web interface to the database with some front end authentication. This is much of the same

code as used in Chapter 24. We have included it here for completeness, but with little discus-

sion.

The administration interface requires a user to log in via the login.php file, which then takes

her to the administration menu, admin.php. Th login page is shown in Figure 25.11. (We have

omitted the login.php file here for brevity—it’s almost exactly the same as the one in Chapter

24. If you want to look at it, it’s on the CD-ROM.) The administration menu is shown in

Figure 25.12.

Building a Shopping Cart

HAPTER 25

UILDING A

SHOPPING CART

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