From 6631fad79091a1d77791f4d152c019d05e3872c0 2015-02-13 00:21:36
From: Min RK <benjaminrk@gmail.com>
Date: 2015-02-13 00:21:36
Subject: [PATCH] handle message arriving when sockets are closed

check both the incoming and outgoing streams
before proceeding to send messages
---

diff --git a/IPython/html/base/zmqhandlers.py b/IPython/html/base/zmqhandlers.py
index 4ddcb5e..f1159e8 100644
--- a/IPython/html/base/zmqhandlers.py
+++ b/IPython/html/base/zmqhandlers.py
@@ -106,12 +106,11 @@ class ZMQStreamHandler(WebSocketHandler):
                 # we can close the connection more gracefully.
                 self.stream.close()
 
-
+    
     def check_origin(self, origin):
         """Check Origin == Host or Access-Control-Allow-Origin.
         
         Tornado >= 4 calls this method automatically, raising 403 if it returns False.
-        We call it explicitly in `open` on Tornado < 4.
         """
         if self.allow_origin == '*':
             return True
@@ -173,7 +172,10 @@ class ZMQStreamHandler(WebSocketHandler):
     def _on_zmq_reply(self, stream, msg_list):
         # Sometimes this gets triggered when the on_close method is scheduled in the
         # eventloop but hasn't been called.
-        if stream.closed(): return
+        if self.stream.closed() or stream.closed():
+            self.log.warn("zmq message arrived on closed channel")
+            self.close()
+            return
         channel = getattr(stream, 'channel', None)
         try:
             msg = self._reserialize_reply(msg_list, channel=channel)