Retrieve a timemap for a URL

Source: R/timemap.r

A TimeMap, as defined in the Memento protocol (RFC 7089), provides an overview of all Mementos (and their archival/version datetimes) known to the responding server.

get_timemap(url, seconds = 180)

Arguments

url

Either an existing timemap URL or a plain resource URL
seconds

(default is 180) This is an expensive operation for the Internet Archive and it can take well-above this 3-minute setting for query results to be delivered. It's highly suggested you monitor your experience and adjust accordingly.

Value

data frame of mementos

Details

A TimeMap (URI-T) for an Original Resource (URI-R) is a machine-readable document that lists the Original Resource itself, its TimeGate, and its Mementos as well as associated metadata such as archival datetime for Mementos. TimeMaps are exposed by systems that host prior versions of Original Resources, and allow for batch discovery of Mementos,

TimeMaps are serialized according to the syntax specified for the value of the HTTP Link header. That format is introduced in RFC 5988, Web Linking RFC, and has media type application/link-format.

Each timemap entry contains:

  • rel : the type of timemap record (i.e. it describes the relationship between the current entry and the linked resource). See Section 2.2 for more information.

  • link : can be the direct link to the original resource or links to the archived copy

  • type : if provided, the type of link

  • from : if provided, a timestamp for the rel == "self" record (should be NA for others)

  • datetime : the timestamp for the memento record

Note

if a supplied resource has many entries, this call can take a while

Examples

# NOT RUN {
rproj_tm <- get_timemap("https://www.r-project.org/")

unique(rproj_tm$rel)
## [1] "original"      "self"          "timegate"      "first memento" "memento"

dplyr::glimpse(rproj_tm)
## Observations: 11,886
## Variables: 5
## $ rel      <chr> "original", "self", "timegate", "first memento", "memento", "mement...
## $ link     <chr> "http://www.r-project.org:80/", "http://web.archive.org/web/timemap...
## $ type     <chr> NA, "application/link-format", NA, NA, NA, NA, NA, NA, NA, NA, NA, ...
## $ from     <chr> NA, "Tue, 20 Jun 2000 19:56:31 GMT", NA, NA, NA, NA, NA, NA, NA, NA...
## $ datetime <chr> NA, NA, NA, "Tue, 20 Jun 2000 19:56:31 GMT", "Wed, 16 Aug 2000 09:5...
# }