An example of creating a barebones web socket server and client in Ruby

websockets.rb

require 'socket'
require 'websocket'
require 'websocket-client-simple'

port = rand(10_000..60_000)

thread = Thread.new do 
  begin
    server = TCPServer.new port
    socket = server.accept

    handshake = WebSocket::Handshake::Server.new
    handshake << socket.gets until handshake.finished?
    socket.write handshake.to_s

    incoming = WebSocket::Frame::Incoming::Server.new version: handshake.version
    incoming << socket.getc until message = incoming.next

    puts message.data
  ensure 
    server.close
  end
end

begin 
  client = WebSocket::Client::Simple.connect "ws://localhost:#{port}"
  client.on(:open) { client.send 'Ruby WebSockets!' }
  thread.join
ensure
  client.close
end