WebSocket client with socketio/engineio - websocket

Question

I have a really simple nodejs app into which I've installed socket.io and engine.io (not at the same time).
I'm trying to connect from a standard WebSocket client (new WebSocket)
The first issue I had is that the client would not connect at all, I've 'fixed' that by setting 'destroy upgrade' to false on the server.
Now the socket is trying to connect (the readystate is 0) but I'm not getting a connection event on the server or an onopen event on the client, so I'm guessing it's never connecting.
Do I need to set anything else to get the connection to happen?
The server is running express and listening on port 3000 (socket.io piggybacks onto the http server created for express)
The client does a
new WebSocket("ws://localhost:3000")
I've also tried
new WebSocket("ws://localhost:3000/socket.io")
As the socket.io docs imply that that is the default endpoint but neither work

Answer 1

I worked this out the old fashioned way (by looking at the network traffic) when what I should have done is look at the signal.io docs, oh well. There are two parts to this, connecting and sending data.
To connect, the client has to negotiate using xhr, so:
var time = new Date().getTime();
$.get("http://localhost:3000/socket.io/1/?t=" + time, function (data) {});
This starts the negotiation that socket io requires. Socket.io returns an id, some timeouts and a list of protocols, all of which I ignore apart from the id
// in the xhr callback function
var key = data.split(":")[0];
var ws = new WebSocket('ws://localhost:3000/socket.io/1/websocket/' + key);
and that connects
To send data to a socket.io server you have to frame the data in the format it expects which is documented here https://github.com/LearnBoost/socket.io-spec
something like
ws.send('5:::{"name":"my other event","args":[{"my":"data"}]}');