Connect to local websocket server

dersar00

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 3749 5

2018-06-14 18:08:30 UTC

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dersar00

@Azolo, I think I need u’r help.

Post #1

Ankhers

Can you show the error that you are getting?

Post #2

dersar00

16:58:37.947 [error] Supervisor 'Elixir.DispatcherService.Supervisor' had child 'Elixir.DispatcherService.Websockets' started with 'Elixir.DispatcherService.Websockets':start_link(<<"ws://localhost:2345">>) at undefined exit with reason #{'__exception__' => true,'__struct__' => 'Elixir.WebSockex.ConnError',original => timeout} in context start_error
16:58:37.947 [error] CRASH REPORT Process <0.260.0> with 0 neighbours exited with reason: {{shutdown,{failed_to_start_child,'Elixir.DispatcherService.Websockets',#{'__exception__' => true,'__struct__' => 'Elixir.WebSockex.ConnError',original => timeout}}},{'Elixir.DispatcherService.Application',start,[normal,[]]}} in application_master:init/4 line 134

16:58:38.020 [info]  Application dispatcher_service exited: DispatcherService.Application.start(:normal, []) returned an error: shutdown: failed to start child: DispatcherService.Websockets
    ** (EXIT) %WebSockex.ConnError{original: :timeout}
16:58:38.020 [info] Application dispatcher_service exited with reason: {{shutdown,{failed_to_start_child,'Elixir.DispatcherService.Websockets',#{'__exception__' => true,'__struct__' => 'Elixir.WebSockex.ConnError',original => timeout}}},{'Elixir.DispatcherService.Application',start,[normal,[]]}}
** (Mix) Could not start application dispatcher_service: DispatcherService.Application.start(:normal, []) returned an error: shutdown: failed to start child: DispatcherService.Websockets
    ** (EXIT) %WebSockex.ConnError{original: :timeout}

Post #3

Azolo

Is that returning CRLFCRLF or just LFLF?

More than likely the browser conventions are more forgiving to the spec than WebSockex. But make sure those are returning carriage returns and line feeds.

Post #4