signaling.js

var https = require('https')
var fs = require('fs')
var WebSocketServer = require('ws').Server;

let app = https
              .createServer(
                  {
                    key: fs.readFileSync(
                        '/etc/letsencrypt/live/rarywebrtc.xyz/privkey.pem'),
                    cert: fs.readFileSync(
                        '/etc/letsencrypt/live/rarywebrtc.xyz/fullchain.pem')
                    // key:  fs.readFileSync("/etc/nginx/cert.key"),
                    // cert: fs.readFileSync("/etc/nginx/cert.crt")
                  },
                  (req, res) => {
                    // ダミーリクエスト処理
                    res.writeHead(200);
                    res.end('All glory to WebSockets!\n');
                  })
              .listen(8080);

// creating a websocket server at port 9090
var wss = new WebSocketServer({server: app});

// all connected to the server users
var users = {};

// when a user connects to our sever
wss.on('connection', function(connection) {
  console.log('User connected');

  // when server gets a message from a connected user
  connection.on('message', function(message) {
    var data;
    // accepting only JSON messages
    try {
      data = JSON.parse(message);
    } catch (e) {
      console.log('Invalid JSON');
      data = {};
    }

    // switching type of the user message
    switch (data.type) {
        // when a user tries to login

      case 'login':
        console.log('User logged', data.name);

        // if anyone is logged in with this username then refuse
        if (users[data.name]) {
          sendTo(connection, {type: 'login', success: false});
        } else {
          // save user connection on the server
          users[data.name] = connection;
          connection.name = data.name;

          sendTo(connection, {type: 'login', success: true});
        }

        break;

      case 'offer':
        // for ex. UserA wants to call UserB
        console.log('Sending offer to: ', data.name);

        // if UserB exists then send him offer details
        var conn = users[data.name];

        if (conn != null) {
          // setting that UserA connected with UserB
          connection.otherName = data.name;

          sendTo(
              conn, {type: 'offer', offer: data.offer, name: connection.name});
        }

        break;

      case 'answer':
        console.log('Sending answer to: ', data.name);
        // for ex. UserB answers UserA
        var conn = users[data.name];

        if (conn != null) {
          connection.otherName = data.name;
          sendTo(conn, {type: 'answer', answer: data.answer});
        }

        break;

      case 'candidate':
        console.log('Sending candidate to:', data.name);
        var conn = users[data.name];

        if (conn != null) {
          sendTo(conn, {type: 'candidate', candidate: data.candidate});
        }

        break;

      case 'leave':
        console.log('Disconnecting from', data.name);
        if (data.name) {
          var conn = users[data.name];
          conn.otherName = null;

          // notify the other user so he can disconnect his peer connection
          if (conn != null) {
            sendTo(conn, {type: 'leave'});
          }
        }

        break;

      default:
        sendTo(
            connection,
            {type: 'error', message: 'Command not found: ' + data.type});

        break;
    }
  });

  // when user exits, for example closes a browser window
  // this may help if we are still in "offer","answer" or "candidate" state
  connection.on('close', function() {
    if (connection.name) {
      delete users[connection.name];

      if (connection.otherName) {
        console.log('Disconnecting from ', connection.otherName);
        var conn = users[connection.otherName];

        if (conn != null) {
          conn.otherName = null;
          sendTo(conn, {type: 'leave'});
        }
      }
    }
  });
});

function sendTo(connection, message) {
  connection.send(JSON.stringify(message));
}