I'm trying to make a chatroom from scratch using Sinatra. I need to detect when a user leaves the page. At first, I was thinking about using a Javascript onbeforeunload function, but then users could actually fake leaving or leave without notifying the server.
My code for the stream part looks like this:
get '/stream', :provides => 'text/event-stream' do
stream :keep_open do |out|
connections << out
end
end
According to one of the Sinatra example files, chat.rb, which basically makes a chatroom, they use
out.callback do
connections.delete(out)
end
but in my test, it didn't fire when I closed the page as a test (in my example, I had it puts something to the console if the code was fired, and nothing was outputted to the console).
Is there a more reliable way to detect if a user leaves the stream?
Also, I'm not using socket.io (client-side) or anything, but I'm open to it if it solves my problem.
Based on chat.rb example, I would create a small protocol to exchange data, instead of just clean chat messages.
With this approach, you can send an "alive signal" for each connection and clean all that doesn't respond.
I adapted a little the chat.rb to illustrate the idea: https://gist.github.com/tlewin/5708745