Socket.io : Get Client sessionID at any point

Question

I know how to retrieve the client sessionID when the user connects.

But I'd like to retrieve it at any time, for example when the client clicks on something, I would like to be able to know who clicked, what their sessionID was.

socket.sessionID doesn't work, nor does socket.handshake.sessionID

For example :

I have this express route :

.get('/result/:survey', function(req, res) {
    res.redirect('/result/'+req.params.survey+'/1');
})

Just before the redirection, I'd like to make the user join a socket room, and also get their sessionID. How could I possibly do that ? According to the doc, it would be socket.join('room') but I doubt socketonly represents the connection I have with the client, and not with the other clients. Maybe I'm just having trouble understanding sockets !

Solution 1

As of version 1.0, you get the client's sessionid this way:

var socket = io();
socket.on('connect', function(){
    var sessionid = socket.io.engine.id;
    ...
});

Solution 2

I'm not sure exactly what you mean, because "when the client clicks on something" assumes that you mean 'client-side' (where you can use socket.socket.sessionid) but "store it in an array of clients" assumes you mean 'server-side' (where you can access it as socket.id).

Client-side:

var socket = io.connect();
socket.on('connect', function() {
  var sessionid = socket.socket.sessionid;
  ...
});

Server-side:

io.sockets.on('connection', function(socket) {
  var sessionid = socket.id;
  ...
});