Advice on implementing “presence” for a web site?

Question

Ideally, I\'d like to find simple, lightweight code that allows all the web clients connected to my site to maintain real-time status of who else is currently online.

<

Answer 1

For real time status, use socket.io. Every time someone connects add them to the connected users list. For accurate stats you will need to keep track of user sessions. See http://www.danielbaulig.de/socket-ioexpress/

var onlineUsers = {};
var online = 0;

io.sockets.on('connection', function (socket) {
  onlineUsers[socket.handshake.sessionID] = socket.handshake.session;
  online = Object.keys(onlineUsers).length;
  socket.broadcast.emit('online', online);

  socket.on('disconnect', function () {
    delete onlineUsers[socket.handshake.sessionID];
    online--;
    socket.broadcast.emit('online', online);
  });
});