Just in case anybody else is interested, it looks like the most convenient way to interact with iRODS repos is through a custom wsgi/python passenger app provided its start up file is called passenger_wsgi.py (see Configuration reference - Nginx - Passenger Library). The advantage of using python in this case comes from the fact that iRODS has a powerful python client API (GitHub - irods/python-irodsclient: A Python API for iRODS).