Socket.io room empty event

Question

I have online file editing application using socket.io. Users join a room that is related with particular file they want to work with. I don't want use file system every time user changes something, so file is cached in memory, but when file is not used anymore I would like to save it on the disk. As far as I know users are removed from a room as soon as they are disconnected. Is there a way to subscribe on "room empty" event?

Answer 1

You could use

socket.on('disconnect', function() {})

and count the number of open connections.

• Torben

Answer 2

If you're managing rooms somehow, then you can use this:

io.sockets.clients('room name');

And this returns socket instances of all client in a room. If the length of this list is 0 then it means file is no longer used by any client and is ready to be saved. Hope this will work!