Built with ruby. It is not spec-compliant neither secure (yet?)
This was just a holiday toy project, following the screencast made by Destroy All Software.
killall ruby; ./server.rb&; sleep 1; curl -v 'http://127.0.0.1:9000/link.txt'
killall ruby; ./server.rb&; sleep 1; curl -v 'http://127.0.0.1:9000/executable.rb'
killall ruby; ./server.rb&; sleep 1; curl -v 'http://127.0.0.1:9000/something_non_existant.html'
killall ruby; ./server.rb&; sleep 1; open 'http://127.0.0.1:9000/link.txt'