Cockpit reverse-proxy written in Ruby

config.ru

require 'surro-gate'
require 'websocket/driver'
require 'rack/reverse_proxy'
require 'permessage_deflate'

class WSRack
  attr_reader :env, :url

  def initialize(env, sock)
    @env = env
    @sock = sock
    @url = "ws://#{env['HTTP_HOST']}#{env['REQUEST_URI']}"
    @driver = WebSocket::Driver.rack(self, :protocols => ['cockpit1'])
    @driver.add_extension(PermessageDeflate)
    @driver.start
  end

  def fetch(length)
    @driver.on(:message) { |msg| yield(msg.data) } if @driver.listeners(:message).length.zero?

    data = @sock.read_nonblock(length)
    @driver.parse(data)
  end

  def issue(data)
    @driver.text(data)
  end

  def write(data)
    @sock.write_nonblock(data)
  end
end

class WSClient
  attr_reader :url

  def initialize(env, sock)
    @sock = sock
    @url = "ws://localhost:9090#{env['REQUEST_URI']}"
    @driver = WebSocket::Driver.client(self, :protocols => ['cockpit1'])
    @driver.add_extension(PermessageDeflate)
    @driver.set_header('Origin', 'http://localhost:9090')
    @driver.set_header('Cookie', env['HTTP_COOKIE'])
    @driver.start
  end

  def fetch(length)
    @driver.on(:message) { |msg| yield(msg.data) } if @driver.listeners(:message).length.zero?

    data = @sock.read_nonblock(length)
    @driver.parse(data)
  end

  def issue(data)
    @driver.text(data)
  end

  def write(data)
    @sock.write_nonblock(data)
  end
end

class Server
  def initialize
    @rp = Rack::ReverseProxy.new do
      reverse_proxy '/', 'http://localhost:9090'
    end
    @sg = SurroGate.new
    @adapters = {}

    Thread.new do
      loop do
        @sg.select(0.1)

        @sg.each_ready do |left, right|
          @adapters[left].fetch(4096) { |data| @adapters[right].issue(data) }
        end
      end
    end
  end

  def call(env)
    if WebSocket::Driver.websocket?(env)
      rsock = env['rack.hijack'].call
      csock = TCPSocket.new('localhost', 9090)

      @adapters[rsock] = WSRack.new(env, rsock)
      @adapters[csock] = WSClient.new(env, csock)

      @sg.push(rsock, csock)

      [-1, {}, []]
    else
      @rp.call(env)
    end
  end
end

run Server.new