dersar00

Connect to local websocket server

Hello, when I try to connect to my local websocket server I got error, but when I connect to wss://echo.websocket.org everything is good. If I try to connect to server through simply js client everything works nice too.

Websocket server:

require 'socket'
require 'digest/sha1'

server = TCPServer.new('localhost', 2345)

loop do

  socket = server.accept
  STDERR.puts "Incoming Request"

  http_request = ""
  while (line = socket.gets) && (line != "\r\n")
    http_request += line
  end

  if matches = http_request.match(/^Sec-WebSocket-Key: (\S+)/)
    websocket_key = matches[1]
    STDERR.puts "Websocket handshake detected with key: #{ websocket_key }"
  else
    STDERR.puts "Aborting non-websocket connection"
    socket.close
    next
  end


  response_key = Digest::SHA1.base64digest([websocket_key, "258EAFA5-E914-47DA-95CA-C5AB0DC85B11"].join)
  STDERR.puts "Responding to handshake with key: #{ response_key }"

  socket.write <<-eos
HTTP/1.1 101 Switching Protocols
Upgrade: websocket
Connection: Upgrade
Sec-WebSocket-Accept: #{ response_key }

  eos

  STDERR.puts "Handshake completed. Starting to parse the websocket frame."

  first_byte = socket.getbyte
  fin = first_byte & 0b10000000
  opcode = first_byte & 0b00001111

  raise "We don't support continuations" unless fin
  raise "We only support opcode 1" unless opcode == 1

  second_byte = socket.getbyte
  is_masked = second_byte & 0b10000000
  payload_size = second_byte & 0b01111111

  raise "All incoming frames should be masked according to the websocket spec" unless is_masked
  raise "We only support payloads < 126 bytes in length" unless payload_size < 126

  STDERR.puts "Payload size: #{ payload_size } bytes"

  mask = 4.times.map { socket.getbyte }
  STDERR.puts "Got mask: #{ mask.inspect }"

  data = payload_size.times.map { socket.getbyte }
  STDERR.puts "Got masked data: #{ data.inspect }"

  unmasked_data = data.each_with_index.map { |byte, i| byte ^ mask[i % 4] }
  STDERR.puts "Unmasked the data: #{ unmasked_data.inspect }"

  STDERR.puts "Converted to a string: #{ unmasked_data.pack('C*').force_encoding('utf-8').inspect }"

  socket.close
end

Websockex worker:

defmodule DispatcherService.Websockets do
  use WebSockex
  require Logger

  def start_link(state \\ []) do
    WebSockex.start_link("wss://echo.websocket.org", __MODULE__, state)
  end

  def handle_connect(_conn, state) do
     Logger.info("Binance Client Connected!")
     {:ok, state}
   end

  def handle_disconnect(%{reason: reason}, state) do
    Logger.warn "websocket closing: #{inspect reason}"
    {:ok, state}
  end

  def handle_frame({:binary, frame}, state) do
    IO.inspect "Received frame"
    {:ok, state}
  end
end

Btw, my js client:

<!doctype html>
<html lang="en">
<head>
  <title>Websocket Client</title>
</head>
<body>
  <script>
    var exampleSocket = new WebSocket("ws://localhost:2345");
    exampleSocket.onopen = function (event) {
      exampleSocket.send("Can you hear me?"); 
    };
    exampleSocket.onmessage = function (event) {
      console.log(event.data);
    }
  </script>
</body>
</html>

5 comments

#websockex #websockets

0 3558 5

2018-06-14 18:08:30 UTC