I am thinking of using SSE to push new data to the client and using Flot(javascript charting library) display "live" updates. My server runs on python Flask framework and I have figured out how to push the data to the client, but the problem occurs as soon as I leave the page:

Exception happened during processing of request from ('127.0.0.1', 38814)
Traceback (most recent call last):File "/usr/lib/python2.7/SocketServer.py", line 582, in process_request_threadself.finish_request(request, client_address)File "/usr/lib/python2.7/SocketServer.py", line 323, in finish_requestself.RequestHandlerClass(request, client_address, self)File "/usr/lib/python2.7/SocketServer.py", line 640, in __init__self.finish()File "/usr/lib/python2.7/SocketServer.py", line 693, in finishself.wfile.flush()File "/usr/lib/python2.7/socket.py", line 303, in flushself._sock.sendall(view[write_offset:write_offset+buffer_size])
error: [Errno 32] Broken pipe

I understand why the error occurs - the socket is never closed due the infinite loop serving up "live" data. Question is how do I detect the page change and cleanly close the socket? Can I close the connection on the client side? How do I detect the page change then?

This is the server code skeleton, I would of course replace the text message with json containing the list of objects to display:

def event_stream():import timewhile True:time.sleep(1)yield "data: This is a message number X.\n\n"@app.route('/stream')
def stream():return Response(event_stream(), mimetype="text/event-stream")

You could use either onBeforeUnload or jQuery's window.unload() to make an Ajax call to some tear down method that closes the handle. Something like:

$(window).unload(function() {$.ajax(type: 'POST',async: false,url: 'foo.com/client_teardown')}
}

There are some inconsistencies with how the unload()/onBeforeUnload() are handled, so you may have some more work to do in something like Chrome.