fix "iTunes Music Library.xml" which has album ratings for non-rated tracks

fix_itunes_rating.rb

#!/usr/bin/env ruby
out = File.open('/tmp/iTunes Music Library.xml', 'w')
in_path = 'iTunes/iTunes Music Library.xml'

regex_rating = /<key>Album Rating<\/key><integer>\d+<\/integer>/
regex_rating_computed_true = /<key>Album Rating Computed<\/key><true\/>/
regex_rating_computed_false = /<key>Album Rating Computed<\/key><false\/>/
regex_last_line = /<\/plist>/
rate_computed = "			<key>Album Rating Computed</key><true/>\n"

line = File.open(in_path).each_cons(2) do |lines|
  out << lines.first unless lines.first =~ regex_rating_computed_false

  if regex_rating =~ lines.first &&
    regex_rating_computed_true !~ lines.last
      out << rate_computed
  end

  out << lines.last if lines.last =~ regex_last_line
end

According to apple, any changes to the file wont be reflected in iTunes. They say the xml is only a read-only copy.