Writing Apache Modules with Perl and C

Preface

One of the minor miracles of the World Wide Web is that it makes client/server network programming easy. With the Common Gateway Interface (CGI) anyone can become a network programmer, creating dynamic web pages, frontends for databases, and even complex intranet applications with ease. If you're like many web programmers, you started out by writing CGI scripts in Perl. With its powerful text-processing facilities, forgiving syntax, and tool-oriented design, Perl lends itself to the small programs that CGI was designed for.

Unfortunately the Perl/CGI love affair doesn't last forever. As your scripts get larger and your server more heavily loaded, you inevitably run into the performance wall. A 1,000-line Perl CGI script that runs fine on a lightly loaded web site becomes unacceptably slow when it increases to 10,000 lines and the hit rate triples. You may have tried switching to a different programming language and been disappointed. Because the main bottleneck in the CGI protocol is the need to relaunch the script every time it's requested, even compiled C won't give you the performance boost you expect.

If your application needs go beyond simple dynamic pages, you may have run into the limitations of the CGI protocol itself. Many interesting things go on in the heart of a web server—things like the smart remapping of URLs, access control and authentication, or the assignment of MIME types to different documents. The CGI protocol doesn't give you access to these internals. ...