Rethinker is a RethinkDB driver for R. It is currently pretty usable, but mileage may vary; the main thing missing is the support for encryption connections, auth keys and v1.0 wire protocol. All those things boil down to the fact that R has no support for cryptographic primitives nor for wrapping connections into TLS.
How to use
The easiest way is to install from CRAN, i.e.,
To build from source, use the standard R build or devtools; for tests, use
devtools::test() (read to the end before doing that).
See wiki for tutorial.
Note that tests will try to spin a throw-away RethinkDB instance in temp with port offset 9876. In some unlikely cases it may interfere with your production DB (when it re-uses port offset 9876 and there is a race condition) or generate a false positive (when RethinkDB fails to start in 5s or some firewall is blocking local traffic, etc.). When RethinkDB is absent or cannot be started, transaction tests will be skipped.