Bringing Web Time Travel to MediaWiki: An Assessment of the Memento MediaWiki Extension

We have implemented the Memento MediaWiki Extension Version 2.0, which brings the Memento Protocol to Medi-aWiki, used by Wikipedia and the Wikimedia Foundation. Test results show that the extension has a negligible impact on performance. Two 302 status code datetime negotia-tion patterns, as defined by Memento, have been examined for the extension: Pattern 1.1, which requires 2 requests, versus Pattern 2.1, which requires 3 requests. Our test re-sults and mathematical review find that, contrary to intu-ition, Pattern 2.1 performs better than Pattern 1.1 due to idiosyncrasies in MediaWiki. In addition to implementing Memento, Version 2.0 allows administrators to choose the optional 200-style datetime negotiation Pattern 1.2 instead of Pattern 2.1. It also permits administrators the ability to have the Memento MediaWiki Extension return full HTTP 4* * and 5* * status codes rather than using standard Me-diaWiki error pages. Finally, version 2.0 permits admin-istrators to turn off recommended Memento headers if de-sired. Seeing as much of our work focuses on producing the correct revision of a wiki page in response to a user’s datetime input, we also examine the problem of finding the correct revisions of the embedded resources, including im-ages, stylesheets, and JavaScript; identifying the issues and discussing whether or not MediaWiki must be changed to support this functionality. 1