Growl notifications for Pianobar

pianobar-notifier.rb

#!/usr/bin/ruby

require 'open-uri'
require 'tempfile'

def cover_art url
  extname = File.extname(url)
  basename = File.basename(url, extname)
  file = Tempfile.new([basename, extname])
  file.binmode
  open(URI.parse(url)) { |data| file.write data.read }
  file
end

trigger = ARGV.shift
if trigger == 'songstart'
  # Get current song information
  songinfo = {}
  STDIN.each_line { |line| songinfo.store(*line.chomp.split('=', 2)) }

  # Grab cover art and send growl notification
  image = cover_art(songinfo['coverArt'])
  `growlnotify -t "Pianobar: Now Playing" -m "#{songinfo['title']}\nby #{songinfo['artist']}" --image "#{image.path}"`

  # Clean up cover art temp file
  image.unlink
  image.close
end

Inspired by the work of Lucas McCoy found here:
http://blog.superuser.com/2011/04/26/listen-to-pandora-in-your-terminal-via-pianobar/#comment-2421

If there's no album art:

|> "Undo The Silence" by "Pulser" on "Miami Trance Anthems" <3
/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/1.8/open-uri.rb:32:in open_uri_original_open': can't convert URI::Generic into String (TypeError) from /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/1.8/open-uri.rb:32:inopen'
from /Users/andrewrich/.config/pianobar/eventcmd.d/pianobar-notify.rb:11:in `cover_art'
from /Users/andrewrich/.config/pianobar/eventcmd.d/pianobar-notify.rb:22