This is a port of Webmachine, actually it is much closer to the ruby version, with a little bit of the javascript version and even some of the python version thrown in for good measure.
It runs atop the Plack framework, but since it really handles the whole HTTP transaction, it is not appropriate to use most middleware modules. (NOTE: I will write more about this in the future.)
This module is extremely young and it is a port of an pretty young (June 2011) module in another language (ruby), which itself is a port of a still kind of young module (March 2009) in yet another language (erlang). But that all said, it really seems like a sane idea and so I stole it and ported it to Perl.
NOTE: More details to come, but for now, this is all.