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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.
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 |
To understand Memento fully, one must realize that 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]
One can find copies of page 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
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