Apache is the most popular web server on the Internet because it is free, reliable, and extensible. The availability of the source code and the modular design of Apache makes it possible to extend web server functionality through the Apache API.
For the most part, however, the Apache API has only been available to C programmers, and requires rebuilding the Apache server from source. mod_perl, the popular Apache module used primarily for enhanced CGI performance, changed all that by making the Apache API available to Perl programmers. With mod_perl, it becomes simple to develop Apache modules with Perl and install them without having to rebuild the web server.
Writing Apache Modules with Perl and C shows how to extend web server capabilities regardless of whether the programming language is Perl or C. The book explains the design of Apache, mod_perl, and the Apache API. It then demonstrates how to use them to perform for tasks like the following:
- Rewriting CGI scripts as Apache modules to vastly improve performance
- Server-side filtering of HTML documents, to embed special markup or code (much like SSI)
- Enhancing server log functionality
- Converting file formats on the fly
- Implementing dynamic navigation bars
- Incorporating database access into CGI scripts
- Customizing access control and authorization to block robots or to use an external database for passwords
The authors are Lincoln Stein and Doug MacEachern. Lincoln is the successful author of How to Set Up and Maintain a World Wide web Site and the developer of the widely used Perl CGI.pm module. Doug is a consultant and the creator of the innovative mod_perl Apache module.
Writing Apache Modules with Perl and C will allow you to enhance your Apache HTTP server in just about any way you'd like. Overall, it is an excellent book, and it has a lot of good information and terrific examples on everything from "Content Handlers" to customizing the Apache server configuration process.
It's quickly apparent that Lincoln Stein and Doug MacEachern spent valuable time writing this book considering the breadth of their subject and the depth they devote to it. The only downside to the book is that it's kind of hard to explain all of the API functionality without assuming a minimum level of competence from the audience. For that reason, this book might be a bit intimidating to novice programmers, but it really rewards you if you put time into it and tinker with things.
The book also works well as a source of ideas and inspiration for when you have to write your own server modules, and I'd recommend it if you want to customize your Apache server or speed up your Perl CGI programs. --Doug Beaver