by Daniel Neis Araujo.
Hello,
you may be interested in https://github.com/danielneis/moodle-auth_ws/
It currently work only with SOAP, but may be trivial to adapt it to support REST too (pull requests are welcome) ;)
There is also another recent forum discussion about this at https://moodle.org/mod/forum/discuss.php?d=319421
Kind regards,
Daniel