1.8 Overview of the Book

The main theme throughout this book is the design and creation of virtual hypermedia documents. A few things to note are:

• All of the examples in the book are in Perl (mostly v4.0, but they should run without problems on v5.0), although some of the common modules are presented in the numerous languages mentioned above.

• When applicable, configuration details are slanted toward the NCSA server, as it is the most commonly used Web server on the Internet.

• The phrases "CGI programs" and "CGI scripts" will be used interchangeably throughout the book.

Chapters 2 through 5 cover the client-server interaction, including a look at the environmental variables, working with forms, and server-side includes (SSI).

From there, we discuss CGI programs that return virtual documents using various MIME content types in Chapter 6, Hypermedia Documents. Dynamic graphic image creation is the highlight of this chapter.

Chapters 7 through 10 cover forms and gateways with a vast number of advanced examples. The creation of static and dynamic forms, as well as communication with various databases and Internet information servers, is presented in great detail.

Chapter 11, Advanced and Creative CGI Applications walks through the design and implementation of a number of advanced CGI applications.

Finally, Chapter 12, Debugging and Testing CGI Applications covers techniques for debugging your CGI programs, and lists some common mistakes and methods for finding your programming errors.

The book also includes appendices with a Frequently Asked Questions list for Perl and CGI, a quick reference for regular expressions (since many examples depend heavily on the use of regular expressions in Perl), an overview of CGI::* modules for Perl 5, an overview of the CGI Lite library, and a list of resources and URLs for more information and CGI-related software.