Installing and Customizing MediaWiki

I was first introduced to the idea of a wiki many years ago. A colleague at work told me about a Web site that invited readers to become writers and editors. Over time, he said, a wiki would grow to include a great deal of knowledge, drawing from the collective experience, without the need for any centrally coordinated assignment or editing. My gut reaction was one of great ambivalence. On the one hand, a community of well-meaning and well-disciplined users could indeed use a wiki in many useful ways. But at the same time, it seemed like an invitation for chaos. And, admittedly, chaos has sometimes been the result.

Over the years, wikis have become increasingly common. Dozens of different software packages are now available, in nearly every programming language and for nearly every Web/database framework. The question is no longer whether a wiki is available, or how easily one can be installed, but rather whether a wiki is an appropriate tool for your needs and which of the existing packages is the best fit for your organization.

And although the jury is still out, at least in part, regarding the long-term viability of public wikis, the amazing Wikipedia Project has demonstrated that it is possible to have surprisingly good results. A research study released several weeks before I wrote this article reported that when it comes to science-related articles, Wikipedia is only slightly less accurate than Encyclopaedia Britanica. Given that Britanica is written and edited by paid experts, while Wikipedia relies on volunteers (who may, of course, still be experts), it is clear that wikis do not necessarily lead to the chaos that I feared.

That said, I have a strong feeling Wikipedia's reputation was preserved not because of the public's inherent love for wikis, but because of a dedicated team of Wikipedians who operate behind the scenes to ensure that the content is viable.

As I wrote above, there are many options for creating a wiki on your own Web server. One of the best-known packages is the same one that powers Wikipedia, known as MediaWiki. In this article, we discuss how you can install MediaWiki on your own server, how you can create and edit static content and how you can even create dynamic special pages.

Although Wikipedia contains an enormous amount of text, the MediaWiki software on which it runs is surprisingly small, straightforward to understand and easy to install. The software itself is written in PHP, and it relies on a MySQL database for content and indexing. That is, none of the pages on a MediaWiki site exist as files on disk; instead, they are created on the fly by the PHP programs, bringing together a number of elements for each individual visitor.

To install the MediaWiki software, you thus need a server running both PHP and MySQL. PHP works on a number of platforms, but we will assume, for the purposes of this article, that you are using the Apache server with relatively recent versions of PHP (at least 4.1.2, although 4.3 is preferred) and MySQL (at least 3.2.x, but 4.0.x is preferred). Most modern Linux distributions either include PHP and MySQL or make them available from on-line repositories without too much trouble. You need administrative privileges for both Apache and MySQL in order to install MediaWiki. If you don't run your own server, you might need to ask the system administrator for some help in modifying the appropriate configuration files.

Although you can download the MediaWiki software directly from SourceForge, you should look for it on the main MediaWiki site, www.mediawiki.org. Once on that page, click on the versions and download link (on the right side of the page), and then on the appropriate link for the current stable release. Download an older or experimental release only if you understand the problems that might be associated with it.

The software comes as a .tar.gz file containing the version number. For example, the file that I downloaded is called mediawiki-1.5.3.tar.gz, indicating that I downloaded version 1.5.3, current as of December 21, 2005. Keep that file in a temporary location (I generally prefer to put such files in a directory named /downloads); we will return to it after taking care of our Apache configuration.

If your site will run only MediaWiki software, there is probably no reason for you to modify your Apache configuration file, traditionally named httpd.conf. In such cases, you can unpack the .tar.gz file in your site's htdocs directory, as described in the instructions on the MediaWiki site. If your distribution uses another directory as its document root, you'll obviously have to adapt to your distribution's preferences.