Memento Project
![](http://upload.wikimedia.org/wikipedia/commons/thumb/d/db/Memento_logo_640.png/220px-Memento_logo_640.png)
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.
Request Header | Response Header | Dimension | Examples | Reference |
---|---|---|---|---|
Accept | Content-Type | content-type of the representation | text/html text/plain image/png | RFC 7231[3] RFC 2616 |
Accept-Language | Content-Language | language of the representation | en en-US cz | RFC 7231 RFC 2616 |
Accept-Encoding | Content-Encoding | medium, typically compression, that the content has been encoded with | compress gzip deflate | RFC 7231 RFC 2616 |
Accept-Charset | Content -Type | the character set used by the web page | iso-8859-5 unicode-1-1 | RFC. 7231 RFC 2616 |
Accept-Datetime | Memento-Datetime | time of the representation | Fri, 15 Aug 2014 13:43:03 GMT | RFC 7089 |
The Last-Modified header provided by HTTP[4] does not necessarily reflect when a particular version of a web page came into existence. Also, the Last-Modified header may not exist in some cases. To provide more information, the Memento-Datetime header has been introduced to indicate when a specific representation of a web page was observed on the web.[5]
![This diagram shows how Memento uses a TimeGate (URI-G) to find the best archived page (URI-M) for a user, given the original resource (URI-R) and a datetime.](http://upload.wikimedia.org/wikipedia/commons/thumb/b/b5/Memento-project-memento-process.png/500px-Memento-project-memento-process.png)
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:
http://timetravel.mementoweb.org/api/json/YYYY/urltoarchive
http://timetravel.mementoweb.org/api/json/YYYYMM/urltoarchive
http://timetravel.mementoweb.org/api/json/YYYYMMDD/urltoarchive
http://timetravel.mementoweb.org/api/json/YYYYMMDDHH/urltoarchive
http://timetravel.mementoweb.org/api/json/YYYYMMDDHHMM/urltoarchive
- or
redirect to a Memento with a datetime that is close to a desired datetime:
http://timetravel.mementoweb.org/memento/YYYY/urltoarchive
http://timetravel.mementoweb.org/memento/YYYYMM/urltoarchive
http://timetravel.mementoweb.org/memento/YYYYMMDD/urltoarchive
http://timetravel.mementoweb.org/memento/YYYYMMDDHH/urltoarchive
http://timetravel.mementoweb.org/memento/YYYYMMDDHHMM/urltoarchive
References
- ^ RFC 7089: HTTP Framework for Time-Based Access to Resource States -- Memento
- ^ Berners Lee, Tim. "Web Architecture: Generic Resources". World Wide Web Consortium (W3C). 1996. http://www.w3.org/DesignIssues/Generic Archived 2015-06-02 at the Wayback Machine
- ^ RFC 7231: Hypertext Transfer Protocol (HTTP/1.1): Semantics and Content
- ^ RFC 7232: Hypertext Transfer Protocol (HTTP/1.1): Conditional Requests
- ^ 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 Archived 2015-05-19 at the Wayback Machine
- ^ "Time Travel APIs". timetravel.mementoweb.org. Archived from the original on 2018-05-21. Retrieved 2018-05-15.
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/