How to access html request parameters for a .rhtml page served by webrick?

Programmer Question

I'm using webrick (the built-in ruby webserver) to serve .rhtml
files (html with ruby code embedded --like jsp).

It works fine, but I can't figure out how to access parameters
(e.g. http://localhost/mypage.rhtml?foo=bar)
from within the ruby code in the .rhtml file.
(Note that I'm not using the rails framework, only webrick + .rhtml files)

Thanks

Find the answer here