Using Socket.IO to show object count within Compound.js

I'm testing out Socket.IO for a new project that uses Compound.js (built on node.js/Express.js), but I've come across a problem. I've managed to get the basics working and the following message works fine:

Server-side JS (applicationname/config/initializers/socketio.js):

var sio = require('socket.io');
var http = require('http');
var activeClients = 0;

module.exports = function (compound) {
    var app = compound.app;
    var server = http.createServer(app);
    compound.server = server;
    var io = compound.io = sio.listen(server);

    io.sockets.on('connection', function (socket) {
        activeClients +=1;

        var connections = setInterval(function () {
            socket.emit('news', { clients: activeClients });
        }, 1000);

        socket.on('disconnect', function () {
            activeClients -= 1;
            io.sockets.emit('user disconnected');
            clearInterval(connections);
        });
    });
}

Front-end JS (applicationname/public/index.html):

<script src="/socket.io/socket.io.js"></script>
<script>
      var socket = io.connect('http://localhost');

      function msgReceived(msg){
        $clientCounter.html(msg.posts);
      }

      $(document).ready(function () {
        $clientCounter = $("#client_count");
        socket.on('news', function (data) {
            msgReceived(data);
            socket.emit('my other event', { my: 'data' });
          });
      });
</script>

What I'm trying to do now is get the number of posts that have been made on the server. I used a default scaffold to generate the Posts method, controller and views.

How do I now find the total number of posts and pass that value to the server-side JS?