Memento Project Explained

Memento is a United States National Digital Information Infrastructure and Preservation Program (NDIIPP)–funded project aimed at making Web-archived content more readily discoverable and accessible to the public.

Technical description

Memento is defined in RFC 7089^[1] as an implementation of the time dimension of content negotiation.^[2] HTTP accomplishes negotiation of content via a variety of headers that allow clients and servers to find content that the user desires.

Dimensions of Content Negotiation Provided by HTTP! Request Header! Response Header! Dimension! Examples! Reference

Accept	Content-Type	content-type of the representation	text/htmltext/plainimage/png	RFC 7231^[3] RFC 2616
Accept-Language	Content-Language	language of the representation	enen-UScz	RFC 7231RFC 2616
Accept-Encoding	Content-Encoding	medium, typically compression, that the content has been encoded with	compressgzipdeflate	RFC 7231RFC 2616
Accept-Charset	Content -Type	the character set used by the web page	iso-8859-5unicode-1-1	RFC. 7231RFC 2616
Accept-Datetime	Memento-Datetime	time of the representation	Fri, 15 Aug 2014 13:43:03GMT	RFC 7089

The header provided by HTTP^[4] does not necessarily reflect when a particular version of a web page came into existence. Also, the header may not exist in some cases. To provide more information, the header has been introduced to indicate when a specific representation of a web page was observed on the web.^[5]

Usage

Copies of page can be found by simply navigating, in a web browser, to a link formatted, replacing urltoarchive with the full URL of the page desired:^[6]

JSON description of a Memento:

<nowiki>http://timetravel.mementoweb.org/api/json/YYYY/</nowiki>''urltoarchive''

<nowiki>http://timetravel.mementoweb.org/api/json/YYYYMM/</nowiki>''urltoarchive''

<nowiki>http://timetravel.mementoweb.org/api/json/YYYYMMDD/</nowiki>''urltoarchive''

<nowiki>http://timetravel.mementoweb.org/api/json/YYYYMMDDHH/</nowiki>''urltoarchive''

<nowiki>http://timetravel.mementoweb.org/api/json/YYYYMMDDHHMM/</nowiki>''urltoarchive''

orredirect to a Memento with a datetime that is close to a desired datetime:

<nowiki>http://timetravel.mementoweb.org/memento/YYYY/</nowiki>''urltoarchive''

<nowiki>http://timetravel.mementoweb.org/memento/YYYYMM/</nowiki>''urltoarchive''

<nowiki>http://timetravel.mementoweb.org/memento/YYYYMMDD/</nowiki>''urltoarchive''

<nowiki>http://timetravel.mementoweb.org/memento/YYYYMMDDHH/</nowiki>''urltoarchive''

<nowiki>http://timetravel.mementoweb.org/memento/YYYYMMDDHHMM/</nowiki>''urltoarchive''

References

1. RFC 7089: HTTP Framework for Time-Based Access to Resource States -- Memento
2. Berners Lee, Tim. "Web Architecture: Generic Resources". World Wide Web Consortium (W3C). 1996. http://www.w3.org/DesignIssues/Generic
3. RFC 7231: Hypertext Transfer Protocol (HTTP/1.1): Semantics and Content
4. RFC 7232: Hypertext Transfer Protocol (HTTP/1.1): Conditional Requests
5. Nelson, Michael L. "2010-11-05: Memento-Datetime is not Last-Modified". Web Science and Digital Libraries Research Group. November 5, 2010. http://ws-dl.blogspot.com/2010/11/2010-11-05-memento-datetime-is-not-last.html
6. Web site: Time Travel APIs. timetravel.mementoweb.org. 2018-05-15. https://web.archive.org/web/20180521224610/http://timetravel.mementoweb.org/guide/api/. 2018-05-21. live.

External links

• Memento Project
• The When of the Web - Extensive information about the proposal and experiment is available in the November 2009 paper
• Memento: Time Travel for the Web
• http://lanlsource.lanl.gov/hello
• http://www.cdlib.org/cdlinfo/2010/02/04/web-archive-discovery-memento-implementation-meeting/