What Express websocket events exist?

Question

I am wondering what websocket events exist So far I have only been using the ws.on('message') event, but I would like to use an event that is triggered when the connection is established and closed. I tried adding ws.on('connection'), but that didn't get triggered.

My code:

app.ws('/', function (ws, req) {
    ws.on('message', function (textChunk) {
            //do stuff
        }
    });
});

Do I need some client side programming to do this?

I tried adding this, but it didn't trigger when I connected from my client.

ws.on('request', function () {
  console.log("request");
});

Answer 1

The function provided to app.ws is the one executed when a new websocket is opened. So use it this way:

app.ws('/', function (ws, req) {

    console.log("New connection has opened!");

    ws.on('close', function() {
        console.log('The connection was closed!');
    });

    ws.on('message', function (message) {
        console.log('Message received: '+message);
    });
});

Answer 2

After looking at the source code for express-ws it looks like you can do the following.

var express = require('express');
var app = express();
var expressWs = require('express-ws')(app);

// get the WebsocketServer instance with getWss()
// https://github.com/HenningM/express-ws/blob/5b5cf93bb378a0e6dbe6ab33313bb442b0c25868/index.js#L72-L74
expressWs.getWss().on('connection', function(ws) {
  console.log('connection open');
});

// ... express middleware

// ... websocket middle ware
app.ws('/', function(ws, req) {
  ws.on('message', function(msg) {
    console.log(msg);
  });
});

app.listen(3000);

---

Old Response

There are the following:

close
error
message
open

https://developer.mozilla.org/en-US/docs/Web/API/WebSocket#Attributes