Apache Tutor

Apache Tutor aims to be the definitive independent online source of help and information for applications built on the Apache webserver. Its primary focus is on applications development - particularly modules - for Apache 2.0 and later, where it aims to fulfil the role of an interactive online book. Both contents and interactivity is important, and the software used provides for multiple authors to contribute to content development, at more than one level.

ApacheTutor was created by applications developer Nick Kew, primarily in response to the lack of good developer documentation for working with Apache 2. Contents are being written over time, and contributions are welcome. All articles are published in an interactive framework, and invite comments (annotations) from readers, as well as online editing.

The Book

Application Development with Apache - The Apache Modules Book

ApacheTutor is the companion site for Nick's Book on Apache application development, the definitive guide for module developers. Here you will find source code for the examples used, (except those from apache.org, webthing.com or explicitly referenced). It will also deal with any FAQs arising from the book.

ISBN: 0-13-240967-4, Prentice Hall Professional Technical Reference

The Book companion pages at this site provide supplementary resources for readers of the book.


The primary purpose of The Apache Modules Book is to serve as an in-depth guide for module developers working with Apache. Nearly all the narrative and examples deal with development in C, including not least how Apache helps C programmers attain levels of productivity usually associated with higher-level and scripting languages.

The first chapter is a non-technical overview, setting the scene and introducing the social, cultural and legal background of Apache. It is followed by an extended technical introduction and overview in three chapters. Chapter 2 is a technical overview of the Apache architecture and API. Chapter 3 introduces the Apache Portable Runtime (APR), a semi-autonomous library that is used throughout Apache and relieves the programmer of the many of the traditional burdens of C programming. Chapter 4 discusses general programming techniques appropriate to working with Apache, to ensure your modules work well across different platforms and environments, remain secure, and don't present difficulties to systems administrators.

The central part of the book moves from the general to the specific. Chapters 5-8 each presents a detailed discussion of an aspect of the core function of a web server: namely, processing HTTP requests. A number of real-life modules are developed. Chapter 5 starts with a HelloWorld example, and takes you to the point where you can duplicate the function of a CGI or PHP script as a module. Chapter 6 describes the request processing cycle and working with HTTP metadata, while chapter 7 goes into more detail about identifying users and handling access control. Chapter 8 presents the filter chain, and techniques for transformation of incoming and outgoing data, with a thorough theoretical exposition and several examples. Chapter 9 completes the core topics by describing how to work with configuration data.

Chapters 10 and 11 are more advanced topics that are nevertheless essential reading for serious application developers. Chapter 10 looks at the mechanics of how the API works, and describes how a module can extend it or introduce an entirely new API or service for other modules. Chapter 11 presents the DBD framework for SQL database applications. Finally, chapter 12 is a brief discussion of troubleshooting and debugging techniques.

The Appendixes are selected documents reproduced from the web. They include Apache legal documents: the License, and Contributor License Agreements covering intellectual property. Finally, the authoritative HTTP standard (RFC 2616) is reproduced in full as reference documentation for developers of web applications.


Developer resources are the original purpose of this site. These should be of interest to application programmers, including module authors and anyone on the learning curve to hacking the core httpd and APR code. The front page for tutorials is here.

Request Processing in Apache · Configuration for Modules · Resource Management in Apache · Connection Pooling in Apache
Introduction to Buckets and Brigades · An architecture for smart filtering in Apache
Annotations and Group Authoring
Smart markup-aware Applications with Apache


In this section, we discuss how Apache may usefully be deployed in a range of different applications.



Commercial consultancy is available from:


The security section at ApacheTutor currently offers reviews of leading books in the area of security with Apache, and an article on filtering information leaks. It may offer additional articles in future.