const fs = require('fs');
const https = require('https');
const WebSocket = require('ws');

const server = new https.createServer({
  key: file.readFileSync('/etc/letsencrypt/live/[...]/privkey.pem'),
  cert: file.readFileSync('/etc/letsencrypt/live/[...]/cert.pem')
});
const wss = new WebSocket.Server({ server });

wss.on('connection', openConnection);

function openConnection (ws) {
  ws.on('message', function incoming(message) {
    console.log('received: %s', message);
  });

  ws.send('something');
}

server.listen(8443);