Question

I finally got Socket.IO to work properly, but I have encountered a strange problem.

I am not sure if this is the best way, but I am using:

io.sockets.clients().length

This returns the number of clients connected to my server. The problem is after a few connects and disconnects of users, the number starts to stay higher than it should be.

For instance, if I connect and ask my friends to, the number goes up which is correct. But when we start to disconnect and reconnect the number does not decrease.

I am running the Node.js and Socket.IO server on a VMware Ubuntu server.

Why is this or is there a better method for finding out how many people are connected to the server?

Answer 1

There is a github issue for this. The problem is that whenever someone disconnects socket.io doesn’t delete ( splice ) from the array, but simply sets the value to “null”, so in fact you have a lot of null values in your array, which make your clients().length bigger than the connections you have in reality.

You have to manage a different way for counting your clients, e.g. something like

socket.on('connect', function() { connectCounter++; });
socket.on('disconnect', function() { connectCounter--; });

It’s a mind buzz, why the people behind socket.io have left the things like that, but it is better explain in the github issue, which I posted as a link!