Project Overview

The goal of the mod_oai project is to bring the efficiency of OAI-PMH to everyday web sites. mod_oai began life as a graduate research project at Old Dominion University, where it continues to be maintained and improved by the computer science department's graduate research staff. Now that major search engines like Google, CiteSeer and MSN have begun to use OAI-PMH, we believe mod_oai will prove to be a popular addition to the Apache web server. See the Resources and Publications pages for additional related information and references.

What is OAI-PMH?

OAI-PMH stands for Open Archives Initiative Protocol for Metadata Harvesting. It was designed to simplify the process of gathering information (metadata) from digital repositories. With OAI-PMH, collecting metadata about digital resources is efficient and flexible. For example, the protocol enables selecting only resources that have a datestamp between date X and date Y, or which are of MIME-type "IMG". A web crawler can quickly get an update on the latest changes to a site by requesting only resources that are new or have changed since its last visit, or it can restrict its crawls to only the HTML-type resources.

Although OAI-PMH has had considerable impact in the field of digital libraries, it is still not widely embraced by the general Web community. In part, this is because enabling the protocol on a standard web site is not trivial. The mod_oai project hopes to achieve broader acceptance of OAI-PMH by making it easy to install and use the protocol on Apache web servers.

Why An Apache Module?

Apache is the most widely-installed web server in the world according to Netcraft, which conducts a monthly web-server survey. An open-source product, Apache is free, reliable, and available for nearly every computer platform in use today. In addition, Apache has defined an extensible module format that allows specific functionality to be incorporated directly into the Web server. This combination of open-source software and web-server extensibility makes an Apache module the ideal tool for providing OAI-PMH functionality to a broad segment of the web market. Thanks to mod_oai, there is now an Apache module that is able to respond to OAI-PMH requests.


mod_oai is developed under the Gnu General Public License (GPL), and is distributed free of charge. To get mod_oai, please see the downloads page.


The mod_oai project has been funded by The Andrew W. Mellon Foundation (2004--2005) and by the Library of Congress (2007--2009). Software for the mod_oai module is developed by Old Dominion University's Computer Science Department, in collaboration with the Digital Research Library of Los Alamos National Laboratory (LANL).

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