config.ru

require './rack_auth_digest'

run Protected.app

ruby_auth_digest.rb

require 'sinatra/base'

class Protected < Sinatra::Base
  get '/' do
    "Hello from protected"
  end
    
  def self.app
    app = Rack::Auth::Digest::MD5.new(Protected.new) do |username|
      {'foo' => 'bar'}[username]
    end
    app.realm = 'Protected Area'
    app.opaque = 'asotjrskw42ptr23")$kamnd'
    app
  end
end