class WEBrick::HTTPServlet::FileHandler

def search_file(req, res, basename)
  langs = @options[:AcceptableLanguages]
  path = res.filename + basename
  if File.file?(path)
    return basename
  elsif langs.size > 0
    req.accept_language.each{|lang|
      path_with_lang = path + ".#{lang}"
      if langs.member?(lang) && File.file?(path_with_lang)
        return basename + ".#{lang}"
      end
    }
    (langs - req.accept_language).each{|lang|
      path_with_lang = path + ".#{lang}"
      if File.file?(path_with_lang)
        return basename + ".#{lang}"
      end
    }
  end
  return nil
end