Thanks @mahinshaw. I can see function handle-index being called. Handler functions have to have two parameters (the error message told me). What is the best way to find out what these parameters are? Also I'm being left with: java.lang.ClassCastException: java.lang.String cannot be cast to clojure.lang.Associative, and not sure where it comes from.

From reading the source I think that env and match are the parameters.

@cjmurphy: correct, your handler should take the env and a match. As a note, you will find the request inside the env.