Tuesday, September 6, 2016

Memento at W3C

Herbert van de Sompel's post at the W3C's blog Memento and the W3C announces that both the W3C's specifications and their Wiki now support Memento (RFC7089):
The Memento protocol is a straightforward extension of HTTP that adds a time dimension to the Web. It supports integrating live web resources, resources in versioning systems, and archived resources in web archives into an interoperable, distributed, machine-accessible versioning system for the entire web. The protocol is broadly supported by web archives. Recently, its use was recommended in the W3C Data on the Web Best Practices, when data versioning is concerned. But resource versioning systems have been slow to adopt. Hopefully, the investment made by the W3C will convince others to follow suit.
This is a very significant step towards broad adoption of Memento. Below the fold, some details.

The specifications and the Wiki use different implementation techniques:
Memento support was added to the W3C Wiki pages by deploying the Memento Extension for MediaWiki. Memento support for W3C specifications was realized by installing a Generic TimeGate Server for which a handler was implemented that interfaces with the versioning capabilities offered by the W3C API.
Herbert, Harihar Shankar and Shawn M. Jones also have a much more detailed blog post covering many of the technical details, and the history leading up to this, starting in 2010 when:
Herbert Van de Sompel presented Memento as part of the Linked Data on the Web Workshop (LDOW) at WWW. The presentation was met with much enthusiasm. In fact, Sir Tim Berners-Lee stated "this is neat and there is a real need for it". Later, he met with Herbert to suggest that Memento could be used on the W3C site itself, specifically for time-based access to W3C specifications.
Even for its inventor, getting things to happen on the Web takes longer than it takes! They conclude with by stressing the importance of Link headers, a point that relates to the Signposting proposal discussed in Signposting the Scholarly Web and Improving e-Journal Ingest (among other things):
Even though the W3C maintains the Apache server holding mementos and original resources, and LANL maintains the systems running the W3C TimeGate software, it is the relations within the Link headers that tie everything together. It is an excellent example of the harmony possible with meaningful Link headers. Memento allows users to negotiate in time with a single web standard, making web archives, semantic web resources, and now W3C specifications all accessible the same way. Memento provides a standard alternative to a series of implementation-specific approaches.
Both posts are well worth reading.

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