I believe the WSGI spec is a bit unclear on this but some WSGI servers can give back control to the app when the connection gets closed. I use Flask and Waitres

I believe the WSGI spec is a bit unclear on this but some WSGI servers can give back control to the app when the connection gets closed. I use Flask and Waitress for long-lived server side events and my app is notified when the client closes the connection before the end of the stream of events.