Apple Music Metadata Matching Script (originally taken from https://cl.ly/C3kK)

meta.rb

#!/usr/bin/env ruby
# by @tapbot_paul
# Don't blame me if this nukes your metadata, formats your drive, kills your kids
# This script goes through any iCloud Matched songs in your iTunes library and tries to update the
# metadata from the iTunes Store
# Will run against entire library
# Known to work with Ruby 1.9.3-p551, macOS 10.12.5, iTunes 12.6.1.25
# install the required gems with the following commands
# sudo gem install json
# sudo gem install rb-appscript
# then run the script with "ruby meta.rb"
require 'appscript'
require 'json'
require 'open-uri'

class Track
  attr_reader :itunes_track

  def initialize(itunes_track)
    @itunes_track = itunes_track
  end

  def itunes_id
    return @itunes_id if !@itunes_id.nil?

    path = @itunes_track.location.get.path
    file_string = File.open(path, 'r').read(1024) # data always seems to be around 600-700 bytes in
    index = file_string.index('song')
    if index
      @itunes_id = file_string[index+4, 4].unpack('N')[0]
    else
      puts "Couldn't find @itunes_track id #{track.name.get}"
    end
  end

  def has_itunes_id?
    !itunes_id.nil?
  end

  def name
    @itunes_track.name.get
  end

  def artist
    @itunes_track.artist.get
  end

  def update(result)
    @itunes_track.artist.set(result['artistName'])
    @itunes_track.album.set(result['collectionName'])
    @itunes_track.name.set(result['trackName'])
    @itunes_track.year.set(Date.parse(result['releaseDate']).year)
    @itunes_track.disc_count.set(result['discCount'])
    @itunes_track.disc_number.set(result['discNumber'])
    @itunes_track.track_count.set(result['trackCount'])
    @itunes_track.track_number.set(result['trackNumber'])
    @itunes_track.genre.set(result['primaryGenreName'])

    # @itunes_track.album_artist.set(result['artistName'])
    @itunes_track.comment.set('')
    @itunes_track.composer.set('')
    @itunes_track.grouping.set('')
    @itunes_track.bpm.set('')
    @itunes_track.lyrics.set('')
  end
end

all_tracks = Appscript.app.by_name("iTunes").library_playlists[1].tracks.get
matched_tracks = Hash.new { |hash, key| hash[key] = [] }

all_tracks.each do |track|
  if track.kind.get == 'Matched AAC audio file'
    matched_track = Track.new(track)
    if matched_track.has_itunes_id?
      matched_tracks[matched_track.itunes_id] << matched_track
    else
      raise "Track #{matched_track.name.inspect} by #{matched_track.artist.inspect} has no iTunes ID"
    end
  end
end

puts "Found #{matched_tracks.size} unique tracks out of #{all_tracks.size} total tracks"

WORK_SIZE = 100
counter = 0

matched_tracks.keys.each_slice(WORK_SIZE).with_index do |track_ids, index|
  puts WORK_SIZE * (index + 1)
  updated_tracks = []
  # Country defaults to US, lang defaults to en
  track_data = JSON.parse(open("http://itunes.apple.com/lookup?id=#{track_ids.join(',')}").read)
  # For retrieving Chinese track data
  # track_data = JSON.parse(open("http://itunes.apple.com/lookup?id=#{track_ids.join(',')}&country=HK&lang=zh_HK").read)
  track_data['results'].each do |result|
    result_id = result['trackId']
    matched_tracks[result_id].each do |track|
      track.update(result)
    end
    counter += 1
    updated_tracks << result_id
  end

  missing_tracks = track_ids - updated_tracks
  if missing_tracks.size > 0
    puts "Missed tracks:"
    puts missing_tracks.inspect
  end
end

puts "Matched #{counter} tracks out of #{matched_tracks.size}"