I'm writing a Rails app that needs to convert an IDN domain name from Punycode into its Unicode equivalent. I tried installing the idn gem that has bindings to GNU LibIDN, but it won't compile the native code. Apparently others have the same issue with Ruby 1.9.x.
I also tried the pure Ruby SimpleIDN gem, but I would prefer something native.
Try the simpleidn gem. It works with Ruby 1.8.7 and 1.9.2.
Edit your Gemfile:
gem 'simpleidn'
then you can enter the command as follows:
SimpleIDN.to_unicode("xn--mllerriis-l8a.com")
=> "møllerriis.com"
SimpleIDN.to_ascii("møllerriis.com")
=> "xn--mllerriis-l8a.com"
Whoops - looks like I found a capable answer shortly after posting (sorry). There is a subtly placed patch from 09/2010 in the bug reports section of the project's RubyForge page. Adding this to my Gemfile now allows me to use the idn library:
gem 'idn', '~> 0.0.2', :git => 'git://github.com/mihu/idn'
Too bad that the gem is apparently abandoned :/