ruby_node.rb

# gem install eventmachine eventmachine_httpserver

require 'eventmachine'
require 'evma_httpserver'

module HttpServer
  include EM::HttpServer

  def process_http_request
    response = EM::DelegatedHttpResponse.new(self)
    response.status = 200
    response.content_type 'text/plain'
    response.content = 'ok'
    response.send_response
  end
end

EM.run do
  EM.start_server "localhost", 8000, HttpServer
end