Jigsaw: A Revolutionary Web Server for Linux

Mr. Haddad exposes the design philosophy and essential features of the Jigsaw web Server, an open-source project from W3C, and provides a brief guide for installing it on Linux.

Jigsaw is the World Wide Web Consortium's (W3C) leading-edge web server platform. It is a full functioning, object-oriented web server written in Java that provides a sample HTTP 1.1 implementation, and offers a variety of features on top of an advanced architecture.

The Jigsaw Web Server is designed to be a demonstration in technology rather than a full-fledged release. Initially, it was intended as a project to experiment new technologies. However, as of Jigsaw 2.0, the server broke the rules of test platforms to be more robust than the average web server, making it worthwhile to take a serious look at its features, potentials and possible future deployment.

Design Philosophy

The design philosophy of Jigsaw is to make it as portable, flexible and extensible as possible, while still providing a functional and robust web server. The design goals are met by having the Jigsaw server run within any Java-supported environment.

At its core, having an object-oriented design and implementation, Jigsaw is nothing more than a set of Java classes and extension modules. Therefore, adding capabilities to the server is not complicated. We can dynamically add our own modules where every resource available to the server is an object, as opposed to a CGI script, and any object is available to end users via HTTP. The server can thus be extended by writing new resource objects. This is the replacement for CGI, where server extensions have to be written as processes. Jigsaw also supports CGI for use with existing CGI scripts.

Jigsaw's developers emphasize providing a well-structured source code, a full set of core Application Program Interfaces (APIs) and a high-quality set of documentation.

These factors offer a complete experimental platform that can be used by as many researchers as possible. This contributes to the success of Jigsaw as an open-source project providing a valuable draft to the future of the HTTP protocol and object-oriented web servers.

Supported Platforms

The Jigsaw server runs on any platform supporting Java. It has been tested on Windows 95/NT and Solaris 2.x. Many people have also reported successful installation and use on other platforms such as OS/2, MacOS, BeOS, Linux, AS-400 and AIX. I installed the Jigsaw server on two workstations powered by Red Hat 6.1 and 6.2, with JDK 1.1.8 and JDK 1.2.2 respectively, and in both cases it worked fine.

Getting Started

To install the Jigsaw server, you need to have JDK installed on your system. Downloading the latest version from http://java.sun.com/ is recommended.

After installing JDK, you need to set up the PATH permanently in the startup file to have access to the JDK bin directory. If you are using the C shell, edit the ~/.cshrc file in your home directory and add the following line:

set path=(/usr/local/jdk1.2.2/bin $path)

Please note that you need to change the path according to your own installation path. Then load the startup file ~/.cshrc to activate the changes just applied.

% source ~/.cshrc
Now you will be able to access the Java binary directory without typing the full path.

Downloading Jigsaw

The latest (non-stable) distribution, Jigsaw 2.1.1, can be downloaded from the W3C home page. It contains the Java source code, the documentation and the pre-compiled classes. The 2.1.1 version, released in March 2000, includes new features such as XML-based serialization, Servlet 2.2 implementation, a new RFC2616 compliant cache, image metadata extraction using content negotiation, as well as digest authentication and ACL-based authentication.

Installation Procedure

Having installed JDK and set your path, you can proceed to install Jigsaw on your Linux system by following three steps:

  1. Unpack the distribution file

  2. Set up the environment

  3. Build the property files

In the following subsections, we will examine each of these steps.