Real World Web Services

Chapter 6. Project 3: Billing and Faxing

If you manage to successfully sell any quantity of items on the Internet, it’s hard to imagine not setting up automated systems to help handle the workload. You see this sort of automation all of the time; for example, you expect an automated system to automatically send a confirmation email when an order has been placed. Upon occasion, however, you may not be fortunate enough to work with individuals that have access to the latest technologies, such as email and the Web (yes, for some people those are the latest technologies). For example, your manufacturing partner may not be up to speed. Even in those situations, you can probably still rely on that old standby—the fax.

This chapter shows how to set up a system whereby you receive a payment notification from PayPal and respond by sending a fax containing the order information. PayPal is the well-known payment processing service, http://www.paypal.com/ (see Figure 6-1). For faxes, we’ll be using the web services provided by InterFAX, http://www.interfax.net/ (shown in Figure 6-2).

Figure 6-1. PayPal instant payment notification web site

PayPal’s development offerings are all listed on the main page, but the specific technology we’re interested in here is Instant Payment Notification (IPN), http://www.paypal.com/cgi-bin/webscr?cmd=p/xcl/rec/ipn-intro-outside. The idea is fairly straight-forward: ...