gogakuondemand.rb (v2.2)

#!/usr/bin/env ruby
# coding: utf-8

# 全講座DLで約20分、約557MB（mp4からmp3への変換はPC能力に依存）

require 'nokogiri'
require 'net/https'
require 'fileutils'

def load_pref
  set_script_dir
  load_pref_file
  load_subjects_file
  set_save_file_dest_dir
end

def set_script_dir
  @script_dir = File.expand_path(File.dirname(__FILE__))
  push_dir(@script_dir)
end

def load_pref_file
  load './pref.rb'
  @select_subjects_jp = []
  pref.each do |k,v|
    @select_subjects_jp << k if v
  end
end

def load_subjects_file
  load './subjects.rb'
  @select_subjects = []
  @subject_urls = subject_urls
  @subjects_jp  = subjects_jp
  @select_subjects_jp.each do |sub_jp|
    @select_subjects << @subjects_jp[sub_jp]
  end
end

def set_save_file_dest_dir
  working_dir = save_file_dest_dir ?
                File.expand_path(File.path(save_file_dest_dir)) :
                File.expand_path(File.dirname(__FILE__))
  Dir.mkdir(working_dir) unless File.directory?(working_dir)
  push_dir(working_dir)
end

def print_download_subjects
  download_subjects = @select_subjects_jp * "、"
  print "ダウンロードする語学講座：#{download_subjects}\n\n"
end

def https_body(url)
  uri = URI.parse(url)
  https = Net::HTTP.new(uri.host, uri.port)
  https.use_ssl = true
  https.ssl_version = :TLSv1
  https.verify_mode = OpenSSL::SSL::VERIFY_PEER
  if uri.query
    https.get(uri.path + '?' + uri.query).body
  else
    https.get(uri.path).body
  end
end

def get_source_urls
  data_hash ={}
  @select_subjects.each do |sub|
    url = "https://cgi2.nhk.or.jp/gogaku/#{@subject_urls[sub]}/listdataflv.xml"
    doc = Nokogiri.XML(https_body(url))
    data_array = doc.xpath("/musicdata/music")
    date = data_array.map { |d| d["hdate"].scan(/(\d+)月(\d+)日/)} \
          .map{ |dt| "#{record_year(dt[0][0].to_i)}_%02d_%02d" % dt.flatten}
    data_hash[sub] = {kouza: data_array[0].values[2]}
    data_array.each_with_index do |d, i|
      data_hash[sub][{date: date[i]}] = data_array[i].values[4]
    end
  end
  data_hash
end

def record_year(record_month)
  now = Time.now
  this_month = now.month
  this_year = now.year
  @record_year = this_month - record_month < 0 ? this_year - 1 : this_year
end

def prepare_download_each_subject(key, value)
  @subject = value[:kouza]
  puts "講座名：#{@subject}"
  subject_dir = File.join(current_dir, key.to_s + "/")
  Dir.mkdir(subject_dir) unless File.directory?(subject_dir)
  subject_dir
end

def each_date_process(value)
  value.each do |k, v|
    next if k == :kouza
    @metadata = {}
    date = k[:date]
    @metadata[:subject] = @subject
    @metadata[:title]   = "#{@subject}_#{date}"
    @metadata[:genre]   = "Speech"
    @metadata[:create]  = "NHK"
    @metadata[:year]    = @record_year.to_s
    puts "日付：#{date}"
    print "ダウンロード中...\n"
    merge_list = make_decrypt_key(v)
    print "ファイル変換中...\n"
    merge_mp4(merge_list)
    convert_mp4_mp3
    delete_temp_files
    print "\n"
  end
end

def make_decrypt_key(subject_code)
  master_m3u8 = "https://nhk-vh.akamaihd.net/i/gogaku-stream/mp4/#{subject_code}/master.m3u8"
  index_m3u8_url = https_body(master_m3u8)[/http.*/]
  source_urls = https_body(index_m3u8_url).lines.grep(/http/).map{ |url| url.strip }
  crypt_key_url = source_urls.shift[/https:\/\/.*/][0..-2]
  @decrypt_bin_key = https_body(crypt_key_url)
  make_merge_list(source_urls)
end

def make_merge_list(urls)
  temp_dir = File.join(current_dir, "temp/")
  Dir.mkdir(temp_dir) unless File.directory?(temp_dir)
  download_and_decrypt_gogaku_files(urls, temp_dir)
end

def download_and_decrypt_gogaku_files(urls, temp_dir)
  merge_list = ""
  max = urls.size
  urls.each_with_index do |url, index|
    uri = URI.parse(url)
    http = Net::HTTP.new(uri.host, uri.port)
    crypt_ts = http.get(uri.path + '?' + uri.query).body
    iv = '%032x' % (index + 1)
    iv_bin = iv.unpack('a2'*16).map{ |x| x.hex }.pack('C'*16)
    temp_mp4_path = File.join(temp_dir, "temp_#{'%03d' % (index + 1)}.mp4")
    merge_list << "#{temp_mp4_path} "
    decrypt_mp4 = decrypt(crypt_ts, @decrypt_bin_key, iv_bin)
    open(temp_mp4_path, "w"){ |f| f.write(decrypt_mp4) }
    progress_bar(index + 1, max, "ファイル")
  end
  print "\n"
  merge_list
end

def progress_bar(progress, max, unit)
  max_digits = max.to_s.size
  print "\r" + "[#{'%-50s' % ('*' * (progress.to_f / max * 50).to_i)}] #{'%*d' % [max_digits, progress]} / #{max} #{unit}"
end

def decrypt(str, key, iv)
  decipher = OpenSSL::Cipher.new("aes-128-cbc")
  decipher.decrypt
  decipher.key = key
  decipher.iv = iv
  decipher.update(str) + decipher.final
end

def merge_mp4(merge_list)
  if is_win?
    IO.popen("type #{merge_list} > #{title_path}.mp4".gsub(%r[/], "\\"))
  else
    IO.popen("cat #{merge_list} > #{title_path}.mp4")
  end
end

def is_win?
  RUBY_PLATFORM.downcase =~ /mswin(?!ce)|mingw|cygwin|bccwin/ ? true : false
end

def convert_mp4_mp3
  command_ffmpeg = %Q[ffmpeg -y -i #{title_path}.mp4 -ab 64k -metadata album="#{@metadata[:subject]}" -metadata title="#{@metadata[:title]}" -metadata genre="#{@metadata[:genre]}" -metadata artist="#{@metadata[:create]}" -metadata date="#{@metadata[:year]}" -id3v2_version 3 #{title_path}.mp3 2>&1]
  IO.popen(command_ffmpeg) do |pipe|
    duration = nil
    progress = 0
    pipe.each("r") do |line|
      if line =~ /: (\d{2}):(\d{2}):(\d{2}).(\d{2}),/
        duration = (($1.to_i * 360000 + $2.to_i * 6000 + $3.to_i * 100 + $4.to_i) / 100.0).round
      end
      if line =~ /time=(\d{2}):(\d{2}):(\d{2}).(\d{2})/
        progress = (($1.to_i * 360000 + $2.to_i * 6000 + $3.to_i * 100 + $4.to_i) / 100.0).round
        progress = duration if duration && progress > duration
      end
      if duration
        progress_bar(progress, duration, "秒")
      end
    end
    print "\n"
  end
end

def delete_temp_files
  temp_dir = File.join(current_dir, "temp/")
  temp_mp4 = Dir.glob(File.join(current_dir, "*.mp4"))
  FileUtils.rm_rf(temp_dir)
  FileUtils.rm_f(temp_mp4)
end

def current_dir
  @pwd
end

def title_path
  File.join(current_dir, @metadata[:title])
end

def push_dir(dir)
  @pwds ||= []
  @pwds.push(dir)
  @pwd = @pwds.last
  Dir::chdir(@pwd)
  @pwd
end

def pop_dir
  @pwds.pop
  @pwd = @pwds.last
  Dir::chdir(@pwd)
  @pwd
end

def gogaku_on_demand
  load_pref
  print_download_subjects
  data_hash = get_source_urls
  data_hash.each do |key, value|
    subject_dir = prepare_download_each_subject(key, value)
    push_dir(subject_dir)
    each_date_process(value)
    pop_dir
  end
  puts "作業終了"
end

gogaku_on_demand