From: Zachary Scott <zachary@...>
Date: 2013-03-19T00:33:06+09:00
Subject: [ruby-core:53507] Re: [ruby-trunk - Bug #8113][Open] ArgumentError: cannot interpret as DNS name: nil

I cannot reproduce this with: ruby 2.1.0dev (2013-03-18 trunk 39805)
[x86_64-linux]

$irb -ropen-uri
open("http://www.ruby-lang.org/") { |f| f.each_line { |line| p line } }

Could you try it without rails?