How to push a message to the client in the browser?

[davidwynter]

I am writing a little chat application. The first thing I need to do is see who else is online, so I keep a list of active client sessions. But from the examples it is not clear how I send a message to an active session. Will they all require to have a callback registered when they login and I use that to notify them of the other chat user wanting to chat with them?

[davidwynter]

Just saw a check in, so you are still working on kontraktor!