Build lang selection master data using Google language_tools page. :-D

langs_builder.rb

# encoding: utf-8

require 'open-uri'
require 'yaml'
require 'rubygems'
require 'nokogiri'

class LangsBuilder
  def dump_langs(writer_or_file)
    if writer_or_file.is_a? String
      File.open(writer_or_file, 'w') do |f|
        dump_langs_to_writer f
      end
    elsif writer_or_file.is_a? IO
      dump_langs_to_writer writer_or_file
    else raise "parameter must be File or IO. But '#{writer_or_file.class}'"
    end
  end
  private
  def dump_langs_to_writer(writer)
    lang_map = build_lang_map
    YAML.dump(lang_map, writer)
  end
  def build_lang_map
    doc = doc_by_lang 'en'
    langs = pickup_langs doc
    lang_map = {}
    langs.each do |lang|
      lang_map[lang] = translation_map(lang)
    end
    lang_map
  end
  def pickup_langs(doc)
    langs = doc.xpath('//a').map { |a| $1 if a['href'] =~ /^http:\/\/www\.google\.com\/intl\/([^\/]+)\/?$/ }.compact
    langs.map { |lang| lang unless lang =~ /^xx-/ }.compact
  end

  def translation_map(lang_for)
    doc = doc_by_lang lang_for
    as = doc.xpath('//a').map { |a| a if (a['href'] =~ /^http:\/\/www\.google\.com\/intl\/[^\/]+\/?$/ && a['href'] !~ /\/xx-.+\/?$/) }.compact
    code_trans_array = as.map { |a| [lang_from_href(a['href']), normalize_text(a.text)] }
    Hash[*code_trans_array.flatten]
  end

  private
  def lang_from_href(href)
    $1 if href =~ /^http:\/\/www\.google\.com\/intl\/([^\/]+)\/?$/
  end
  def normalize_text(text)
    text.gsub(/（/, '(').gsub(/）/, ')')
  end
  def doc_by_lang(lang)
    @doc_by_lang ||= {}
    @doc_by_lang[lang] ||= Nokogiri::HTML(open("http://www.google.com/language_tools?hl=#{lang}").read)
  end
end

LangsBuilder.new.dump_langs(ARGV[0])