websocket: Improve detection of closing websocket connections

This eliminates the possibility of messages (especially pings) being
sent in the middle of the closing process (which is generally harmless
but results in errors being logged).

Fixes #2447

diff --git a/tornado/websocket.py b/tornado/websocket.py
index 5398180aa32a9469afc070e69c3a419e88d1d4cd..d2994c1c90d5129824516459a40cdd652353f03c 100644 (file)
--- a/tornado/websocket.py
+++ b/tornado/websocket.py
@@ -248,7 +248,7 @@ class WebSocketHandler(tornado.web.RequestHandler):
            Consistently raises `WebSocketClosedError`. Previously could
            sometimes raise `.StreamClosedError`.
         """
-        if self.ws_connection is None:
+        if self.ws_connection is None or self.ws_connection.is_closing():
             raise WebSocketClosedError()
         if isinstance(message, dict):
             message = tornado.escape.json_encode(message)
@@ -355,7 +355,7 @@ class WebSocketHandler(tornado.web.RequestHandler):
 
         """
         data = utf8(data)
-        if self.ws_connection is None:
+        if self.ws_connection is None or self.ws_connection.is_closing():
             raise WebSocketClosedError()
         self.ws_connection.write_ping(data)
 
@@ -1046,6 +1046,17 @@ class WebSocketProtocol13(WebSocketProtocol):
             self._waiting = self.stream.io_loop.add_timeout(
                 self.stream.io_loop.time() + 5, self._abort)
 
+    def is_closing(self):
+        """Return true if this connection is closing.
+
+        The connection is considered closing if either side has
+        initiated its closing handshake or if the stream has been
+        shut down uncleanly.
+        """
+        return (self.stream.closed() or
+                self.client_terminated or
+                self.server_terminated)
+
     @property
     def ping_interval(self):
         interval = self.handler.ping_interval
@@ -1073,7 +1084,7 @@ class WebSocketProtocol13(WebSocketProtocol):
 
         Called periodically if the websocket_ping_interval is set and non-zero.
         """
-        if self.stream.closed() and self.ping_callback is not None:
+        if self.is_closing() and self.ping_callback is not None:
             self.ping_callback.stop()
             return