Automatically and temporarily exposes a little Rack server on your firewall for testing purposes. Requires UPnP to be enabled on your firewall to work.

config.ru

EXTERNAL_PORT = 42063

require 'UPnP'
upnp = UPnP::UPnP.new(true, 10)
upnp.addPortMapping(EXTERNAL_PORT, 9292, UPnP::Protocol::TCP, "Test Port")
at_exit{upnp.deletePortMapping(EXTERNAL_PORT, UPnP::Protocol::TCP)}
puts "Call externally: http://#{upnp.externalIP}:#{EXTERNAL_PORT}"

run proc{|env| p :env => env; [200, {"Content-Type" => "text/html"}, ["success\n"]]}