Intro to Mementos

Bob Rudis

2018-09-18

Source: vignettes/intro-to-mementos.Rmd

We can use wayback to look at many historical things. Here’s how to dive into saved site RSS feeds. We’ll search the Internet Archive for these saved RSS feed documents (“mementos”). You can research a bit more about web archiving terminology (it’s a bit arcane — at times — IMO) via http://www.mementoweb.org/guide/quick-intro/ & https://mementoweb.org/guide/rfc/ as starter resources.

First, we get the recorded mementos (basically a short-list of relevant content):

The calendar-menu viewer thing at IA is really the “timemap”. I like to work with this as it’s the point-in-time memento list of all the crawls. It’s the second link above so we’ll read it in:

The content is in the mementos and there should be as many mementos there as you see in the calendar view. We’ll read in the first one:

Ideally use writeLines(), now, to save this to disk with a good filename. Alternatively, stick it in a data frame with metadata and saveRDS() it. But, that’s not a format others (outside R) can use so perhaps do the data frame thing and stream it out as ndjson with jsonlite::stream_out() and compress it during save or afterwards.

Then convert it to something we can use programmatically with xml2::read_xml() or xml2::read_html() (RSS is sometimes better parsed as XML):

read_memento() has an as parameter to automagically parse the result but I like to store the mementos locally (as noted previously) so as not to abuse the IA servers (i.e. if I ever need to get the data again I don’t have to hit their infrastructure).

A big caveat is that if you try to get too many resources from the IA in a short period of time you’ll get temporarily banned as they have scale but it’s a free service and they (rightfully) try to prevent abuse.