R Client for Various CrossRef APIs.
Crossref APIs
rcrossref interacts with the main Crossref metadata search API at https://github.com/CrossRef/rest-api-doc, the old metadata search API at http://search.labs.crossref.org/, their DOI Content Negotiation service at http://citation.crosscite.org/docs.html, and the Text and Data Mining project http://tdmsupport.crossref.org/
Crossref's API issue tracker lives at https://gitlab.com/crossref/issues it's a good place to go ask them about things related to their API that go beyond the R interface here.
Defunct
See rcrossref-deprecated and rcrossref-defunct for details.
What am I actually searching?
When you use the cr_*() functions in this package, you are using
the Crossref search API described at
https://github.com/CrossRef/rest-api-doc
When you search with query terms, on Crossref servers they are not searching
full text, or even abstracts of articles, but only what is available in the
data that is returned to you. That is, they search article titles, authors,
etc. For some discussion on this, see
https://gitlab.com/crossref/issues/issues/101
Rate limiting
From time to time Crossref needs to impose rate limits to ensure that
the free API is usable by all. Any rate limits that are in effect will
be advertised in the X-Rate-Limit-Limit and
X-Rate-Limit-Interval HTTP headers.
This boils down to: they allow X number of requests per some time period.
The numbers can change so we can't give a rate limit that will always
be in effect. If you're curious pass in verbose = TRUE to
your function call, and you'll get headers that will display these rate
limits.
Be nice and share your email with Crossref
The Crossref team encourage requests with appropriate contact information and will forward you to a dedicated API cluster for improved performance when you share your email address with them. https://github.com/CrossRef/rest-api-doc#good-manners--more-reliable-service
To pass your email address to Crossref via this client, simply store it
as environment variable in .Renviron like this:
Open file:
file.edit("~/.Renviron")Add email address to be shared with Crossref
crossref_email = name@example.comSave the file and restart your R session
Don't wanna share your email any longer? Simply delete it from
~/.Renviron
Text mining
All Crossref specific text mining functions are now deprecated, and
moved to a new package crminer.
Another package fulltext is designed solely to do general purpose text mining involving Crossref and other sources of scholarly metadata and full text.
High and Low Level APIs
For the Crossref search API (the functions cr_funders(),
cr_journals(), cr_licenses(),
cr_members(), cr_prefixes(), cr_types(),
cr_works()), there is a high level API and a low level. The
high level is accessible through those functions just listed (e.g.,
cr_works()), whereas the low level is accessible via the same
fxn name with an underscore (e.g., cr_works_()). The high level
API does data requests, and parses to data.frame's. Since the high level
API functions have been around a while, we didn't want to break their
behavior, so the low level API functions are separate, and only do the data
request, giving back json or a list, with no attempt to parse any further. The
low level API functions will be faster because there's much less parsing, and
therefore less prone to potential errors due to changes in the Crossref API
that could cause parsing errors. Note that cursor feature works with both
high and low level.
RStudio Addin
On installation of rcrossref you get an RStudio Addin. To use the Addin,
go to the top toolbar > Tools > Addins > Add Crossref Citations. You'll get a
window pop up that you can put in DOIs for. If the DOI is found, the bibtex
citations will be added to a file called crossref.bib. New citations
will be appended to that file. Addin authored by Hao Zhu
https://github.com/haozhu233