upgrade event (http.ClientRequest)

Event: 'upgrade'

function (response, socket, head) { }

Emitted each time a server responds to a request with an upgrade. If this event isn't being listened for, clients receiving an upgrade header will have their connections closed.

A client server pair that show you how to listen for the 'upgrade' event.

const http = require('http');
 
// Create an HTTP server
var srv = http.createServer( (req, res) => {
  res.writeHead(200, {'Content-Type': 'text/plain'});
  res.end('okay');
});
srv.on('upgrade', (req, socket, head) => {
  socket.write('HTTP/1.1 101 Web Socket Protocol Handshake\r\n' +
               'Upgrade: WebSocket\r\n' +
               'Connection: Upgrade\r\n' +
               '\r\n');
 
  socket.pipe(socket); // echo back
});
 
// now that server is running
srv.listen(1337, '127.0.0.1', () => {
 
  // make a request
  var options = {
    port: 1337,
    hostname: '127.0.0.1',
    headers: {
      'Connection': 'Upgrade',
      'Upgrade': 'websocket'
    }
  };
 
  var req = http.request(options);
  req.end();
 
  req.on('upgrade', (res, socket, upgradeHead) => {
    console.log('got upgraded!');
    socket.end();
    process.exit(0);
  });
});

Links:

https://nodejs.org/dist/latest-v5.x/docs/api/http.html#http_event_upgrade

doc_Nodejs

2025-01-10 15:47:30

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