Laravel - Api: Find online users and send notifications

I am building a web service for an android application. When a request comes to the server, I need to send notification to some online users who satisfy some criteria. So, in the first place, I need to know which users are online, get their attributes in database then find the appropriate ones and send notification.

Finding the online users and sending notification are what I have no idea how to implement. I would be appreciated for any suggestion.

Thanks in advance.

via Chebli Mohamed