How to track the number of anonymous users server-side in Meteor?

Question

I\'m writing a data-sensitive application in Meteor, and am trying to limit the client access to as much information as possible. Therefore, I want to implement server side a wa

Answer 1

Checkout the GitHub project howmanypeoplearelooking

Meteor application test to show how many users are online right now.

Answer 2

For the sake of completeness, it's probably best to combine the two answers above. In other words, do the following:

• Keep the online status in Meteor.users, as opposed to a separate collection, as in https://github.com/erundook/meteor-profile-online
• Keep track of disconnections via callback, instead of a heartbeat, as in https://github.com/murilopolese/howmanypeoplearelooking

This would probably be the canonical way to implement this in Meteor. I've created this as a smart package that you can install with Meteorite: https://github.com/mizzao/meteor-user-status

Answer 3

Thanks to Sorhus' tip, I managed to solve this. His answer contains a heartbeat, which I was keen to avoid. However, it contained the trick of using Meteor's "bindEnvironment". This allows access to a collection, which otherwise would not be accessible.

Meteor.publish("whatever", function() {
  userId = this.userId;
  if(userId) Stats.update({}, {$addToSet: {users: userId}});
  else Stats.update({}, {$inc: {users_anon: 1}});

  // This is required, because otherwise each time the publish function is called,
  // the events re-bind and the counts will start becoming ridiculous as the functions
  // are called multiple times!
  if(this.session.socket._events.data.length === 1) {

    this.session.socket.on("data", Meteor.bindEnvironment(function(data) {
      var method = JSON.parse(data).method;

      // If a user is logging in, dec anon. Don't need to add user to set,
      // because when a user logs in, they are re-subscribed to the collection,
      // so the publish function will be called again.
      // Similarly, if they logout, they re-subscribe, and so the anon count
      // will be handled when the publish function is called again - need only
      // to take out the user ID from the users array.
      if(method === 'login')
        Stats.update({}, {$inc: {users_anon: -1}});

      // If a user is logging out, remove from set
      else if(method === 'logout')
        Stats.update({}, {$pull: {users: userId}});

    }, function(e) {
      console.log(e);
    }));

    this.session.socket.on("close", Meteor.bindEnvironment(function() {
      if(userId === null || userId === undefined) 
        Stats.update({}, {$inc: {users_anon: -1}});
      else
        Stats.update({}, {$pull: {users: userId}});
    }, function(e) {
      console.log("close error", e);
    }));
  }
}