itunes_rate_with_hotkey.rb

#!/usr/bin/env ruby

require 'ubygems'
require 'osx/cocoa'
require 'osx/hotkey'
require 'rbosa'
require 'g'

def starrize(rating, max = 5)
  '★' * rating + '☆' * (max - rating)
end

itunes = OSA.app('iTunes')
app = NSApplicationWithHotKey.sharedApplication

(0..5).to_a.each do |rating|
  app.register_hotkey("Command+%i" % rating) do
    track = itunes.current_track
    track.rating = rating * 20
    g '%s %s - %s' % [starrize(rating), track.artist, track.name]
  end
end

app.run