Chapter 16. CGI and Perl

16.1. The World of CGI

Very few serious sites nowadays can do without scripts in one way or another. If you want to interact with your visitors — even as simply as "Hello John Doe, thanks for visiting us again" (done by checking his cookie (as described later in this chapter) against a database of names), you need to write some code. If you want to do any kind of business with him, you can hardly avoid it. If you want to serve up the contents of a database — the stock of a shop or the articles of an encyclopedia — a script might be a useful way to do it. Scripts are typically, though not always, interpreted, and they are generally an easier approach to gluing pieces together than the write and compile cycle of more formal programs.

Writing scripts brings together a number of different packages and web skills whose documentation is sometimes hard to find. Until all of it works, none of it works; so we thought it might be useful to run through the basic elements here and to point readers at sources of further knowledge.