server.js

const http = require('http');
const httpProxy = require('http-proxy');

const proxy = httpProxy.createProxyServer({
  target: {
    host: 'pulsar-host',
    port: 8080
  }
});


const server = http.createServer((req, res) => {
  res.writeHead(404); // We only accept ws requests
  res.end();
});

server.on('upgrade', (req, socket, head) => {
  // Authenticate your client here
  
  // if authentication is successfull then:
  proxy.ws(req, socket, head);
  
  // if authentication fails then:
  socket.destroy();
});

server.listen(8080);