raw socket websocket client

client.js

var net = require('net');

var socket = net.connect(8080, "localhost", () => {
  var request = "GET / HTTP/1.1\r\nHost: " + "localhost" + "\r\n\r\n";
  var rawResponse = "";

  socket.write(`
    GET / HTTP/1.1
    Host: localhost
    Connection: Upgrade
    Upgrade: websocket
    Sec-WebSocket-Version: 13
    Sec-WebSocket-Key: IS0tZXhhbXBsZS5haS0tIQ==
    Origin: localhost

  `.split("\n").map(x=>x.trim()).splice(1).join("\r\n"));

  setInterval(()=>{
    var message = "Ahoj toto je sprava! " + new Date();
    var buf = new Buffer(message.length + 8);
    buf[0] = 0x81;
    buf[1] = 126 | 0x80;
    buf[2] = message.length >> 8; // TODO: this breaks rfc6455 Payload length rules, but works
    buf[3] = message.length & 255;
    buf[4] = buf[5] = buf[6] = buf[7] = 0;
    for (var i=0; i<message.length; i++)
      buf[i+8] = message.charCodeAt(i);
    socket.write(buf);
  }, 1000)

  socket.on('data', function(chunk) {
    if (chunk[0] == 0x81 || chunk[0] == 0x82)  // text frame, binary frame
    {
      var msg = "";
      var ofs = 2;
      var len = chunk[1];
      if (len == 126)
      {
        ofs = 4;
        len = (chunk[2]<<8) | chunk[3];
      }
      for (var i=0; i<len; i++)
        msg += String.fromCharCode(chunk[i+ofs]);
      console.log("WS:" + msg);
    } else
      console.log("RAW:" + chunk.toString());
  });
  socket.on('end', function(){
      console.log(rawResponse);
  });
});

server.js

const WebSocket = require('ws');
const server = new WebSocket.Server({port: 8080});
let sockets = [];
server.on('connection', function(socket) {
  sockets.push(socket);
  socket.on('message', function(msg) {
    console.log(msg.toString());
    sockets.forEach(s => s.send(msg));
  });
  socket.on('close', function() {
    sockets = sockets.filter(s => s !== socket);
  });
});

websocket.ino

#define SerialDebug Serial
#define DEBUG_ETHERNET_GENERIC_PORT SerialDebug
#define _ETG_LOGLEVEL_ 0
#define USE_THIS_SS_PIN 10
#define SENDCONTENT_P_BUFFER_SZ 512
#include <SPI.h>
#define ETHERNET_LARGE_BUFFERS
#include "Ethernet_Generic.h"

byte mac[] = { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0x01 };
IPAddress ip(192, 168, 2, 222);
EthernetClient client;

void WsReceive()
{
  char buffer[64];
  int bufferi = 0;
  while (client.available())
    buffer[bufferi++] = client.read();

  if (bufferi)
  {
    Serial.print("Received ");
    Serial.print((int)bufferi);
    Serial.print(" bytes: ");
    buffer[bufferi] = 0;
    if ((uint8_t)buffer[0] == 0x81 || (uint8_t)buffer[0] == 0x82)
    { 
      if (buffer[1] < sizeof(buffer))
        buffer[buffer[1]+2] = 0;
      Serial.print(buffer+2);
      Serial.print("\n");
    } else {
      Serial.print("<Wrong websocket frame>");
      Serial.print(buffer[0], HEX);
      Serial.print(">\n");
    }
  }
}

void setup()
{
  SerialDebug.begin(115200);
  SerialDebug.print("\nStarting WebClient\n");
  Ethernet.init (USE_THIS_SS_PIN);
  Ethernet.begin(mac, ip);
  //Ethernet.begin(mac);

  SerialDebug.print(F("Connected! IP address: "));
  SerialDebug.println(Ethernet.localIP());

  if ( (Ethernet.getChip() == w5500) || (Ethernet.getChip() == w6100) || (Ethernet.getAltChip() == w5100s) )
  {    
    SerialDebug.print(F("Speed: "));
    SerialDebug.print(Ethernet.speedReport());
    SerialDebug.print(F(", Duplex: "));
    SerialDebug.print(Ethernet.duplexReport());
    SerialDebug.print(F(", Link status: "));
    SerialDebug.println(Ethernet.linkReport());
  }
  delay(100);
}

void WsSend(const char* message)
{
  int len = strlen(message);
  char buffer[64] = {0};
  buffer[0] = 0x81;
  buffer[1] = 0xfe;
  buffer[2] = len >> 8;
  buffer[3] = len & 255;
  for (int i=0; message[i]; i++)
    buffer[i+8] = message[i];
  client.write(buffer, len+8);
}

bool processHeader(void (*handler)(const char*, const char*)) //(std::function<void(const char*, const char*)> handler)
{
  const int timeout = 300;
  long t0 = millis();
  char line[128];
  int linei = 0;
  char buf[5] = {0};

  while (millis() - t0 < timeout && client.connected())
  {
    if (!client.available())
      continue;
    t0 = millis();
    while (client.available())
    {
      char c = client.read();
      
      buf[0] = buf[1];
      buf[1] = buf[2];
      buf[2] = buf[3];
      buf[3] = c;
      if (strcmp(buf, "\r\n\r\n") == 0)
        return true;

      if (c == 0x0d || c == 0x0a)
      {
        line[linei] = 0;
        if (linei)
        {
          char *delim = strstr(line, ": ");
          if (delim)
          {
            *delim = 0;
            for (int i=0; line[i]; i++)
              if (line[i] >= 'A' && line[i] <= 'Z')
                line[i] -= 'A' - 'a';
            handler(line, delim+2);
          }
        }
        linei = 0;
      } else {
        if (linei < sizeof(line)-1)
          line[linei++] = c;
      }
    }
  } 
  return false;
}

void loop()
{
  static int failedTries = 0;
  static long lastTimestamp = 0;
  
  if (client.available())
    WsReceive();
    
  long now = millis();
  if (now - lastTimestamp < 300)
    return;
  
  lastTimestamp = now;

  if (!Ethernet.link())
  {
    Serial.print("No link\n");
    return;
  }
  
  if (client.connected())
  {
    char message[64];
    sprintf(message, "Toto je sprava %ld!", millis());
    WsSend(message);
    Serial.print(".");
    return;
  }

  Serial.print("Connecting...\n");

  if (client.connect(IPAddress(192, 168, 2, 1), 8080))
  {
    client.print("GET / HTTP/1.1\r\n"    
    "Host: 192.168.2.1\r\n"
    "Connection: Upgrade\r\n"
    "Upgrade: websocket\r\n"
    "Sec-WebSocket-Version: 13\r\n"
    "Sec-WebSocket-Key: IS0tZXhhbXBsZS5haS0tIQ==\r\n"
    "Origin: localhost\r\n"
    "\r\n");
    
    processHeader([](const char* head, const char* value){
      // upgrade=websocket
      // connection=Upgrade
      // sec-websocket-accept=...
      Serial.print("header: ");
      Serial.print(head);
      Serial.print("=");
      Serial.print(value);
      Serial.print("\n");
    });
    failedTries = 0;
  } else 
  {
    SerialDebug.println(F("Server not available"));
    if (failedTries++ >= 5)
    {
      failedTries = 0;
      SerialDebug.println(F("Ethernet reset"));
      Ethernet.init (USE_THIS_SS_PIN);
      Ethernet.begin(mac, ip);
    }
  }
}