websockets: socket.send() raised exception

Hi,

I have an issue with running a simple example (paraphrased from https://websockets.readthedocs.org/en/stable/intro.html). I’m testing with Python 3.4.2 (Debian Jessie default) and websockets from master. Consider the following code:

# server.py
import asyncio
import websockets

@asyncio.coroutine
def send(websocket, path):
    while True:
        if not websocket.open:
            return
        yield from websocket.send('message')

start_server = websockets.serve(send, 'localhost', 8765)
asyncio.get_event_loop().run_until_complete(start_server)
asyncio.get_event_loop().run_forever()

# client.py
import asyncio
import websockets

@asyncio.coroutine
def recv(uri):
    websocket = yield from websockets.connect(uri)
    while True:
        message = yield from websocket.recv()
        print(message)

asyncio.get_event_loop().run_until_complete(recv('ws://localhost:8765'))

I run python server.py in one terminal and python client.py in another. After I ^C the client, the server starts printing socket.send() raised exception. and does not accept new connections.

After I ^C the server I get the following output:

socket.send() raised exception.
socket.send() raised exception.
socket.send() raised exception.
socket.send() raised ex^C
Traceback (most recent call last):
  File "server.py", line 13, in <module>
    asyncio.get_event_loop().run_forever()
  File "/usr/lib/python3.4/asyncio/base_events.py", line 244, in run_forever
    self._run_once()
  File "/usr/lib/python3.4/asyncio/base_events.py", line 1081, in _run_once
    handle._run()
  File "/usr/lib/python3.4/asyncio/events.py", line 120, in _run
    self._callback(*self._args)
  File "/usr/lib/python3.4/asyncio/tasks.py", line 291, in _wakeup
    self._step(value, None)
  File "/usr/lib/python3.4/asyncio/tasks.py", line 235, in _step
    result = coro.send(value)
  File "/env/lib/python3.4/site-packages/websockets/server.py", line 77, in handler
    yield from self.ws_handler(self, path)
  File "server.py", line 9, in send
    yield from websocket.send('message')
  File "/env/lib/python3.4/site-packages/websockets/protocol.py", line 261, in send
    yield from self.write_frame(opcode, data)
  File "/env/lib/python3.4/site-packages/websockets/protocol.py", line 430, in write_frame
    write_frame(frame, self.writer.write, is_masked)
  File "/env/lib/python3.4/site-packages/websockets/framing.py", line 149, in write_frame
    writer(output.getvalue())
  File "/usr/lib/python3.4/asyncio/streams.py", line 269, in write
    self._transport.write(data)
  File "/usr/lib/python3.4/asyncio/selector_events.py", line 613, in write
    logger.warning('socket.send() raised exception.')
  File "/usr/lib/python3.4/logging/__init__.py", line 1286, in warning
    self._log(WARNING, msg, args, **kwargs)
  File "/usr/lib/python3.4/logging/__init__.py", line 1409, in _log
    self.handle(record)
  File "/usr/lib/python3.4/logging/__init__.py", line 1419, in handle
    self.callHandlers(record)
  File "/usr/lib/python3.4/logging/__init__.py", line 1489, in callHandlers
    lastResort.handle(record)
  File "/usr/lib/python3.4/logging/__init__.py", line 853, in handle
    self.emit(record)
  File "/usr/lib/python3.4/logging/__init__.py", line 981, in emit
    stream.write(self.terminator)
KeyboardInterrupt
--- Logging error ---
Traceback (most recent call last):
--- Logging error ---
Traceback (most recent call last):
Exception ignored in: <bound method Task.__del__ of <Task finished coro=<handler() done, defined at /env/lib/python3.4/site-packages/websockets/server.py:54> exception=KeyboardInterrupt()>>
Traceback (most recent call last):
  File "/usr/lib/python3.4/asyncio/tasks.py", line 93, in __del__
  File "/usr/lib/python3.4/asyncio/futures.py", line 218, in __del__
  File "/usr/lib/python3.4/asyncio/base_events.py", line 950, in call_exception_handler
  File "/usr/lib/python3.4/logging/__init__.py", line 1303, in error
  File "/usr/lib/python3.4/logging/__init__.py", line 1409, in _log
  File "/usr/lib/python3.4/logging/__init__.py", line 1419, in handle
  File "/usr/lib/python3.4/logging/__init__.py", line 1489, in callHandlers
  File "/usr/lib/python3.4/logging/__init__.py", line 853, in handle
  File "/usr/lib/python3.4/logging/__init__.py", line 984, in emit
  File "/usr/lib/python3.4/logging/__init__.py", line 906, in handleError
  File "/usr/lib/python3.4/traceback.py", line 169, in print_exception
  File "/usr/lib/python3.4/traceback.py", line 153, in _format_exception_iter
  File "/usr/lib/python3.4/traceback.py", line 18, in _format_list_iter
  File "/usr/lib/python3.4/traceback.py", line 65, in _extract_tb_or_stack_iter
  File "/env/lib/python3.4/linecache.py", line 15, in getline
  File "/env/lib/python3.4/linecache.py", line 41, in getlines
  File "/env/lib/python3.4/linecache.py", line 126, in updatecache
  File "/env/lib/python3.4/tokenize.py", line 437, in open
AttributeError: 'module' object has no attribute 'open'
Task was destroyed but it is pending!
task: <Task pending coro=<run() running at /env/lib/python3.4/site-packages/websockets/protocol.py:299> wait_for=<Future finished result=True>>

Is this an expected behaviour? Perhaps there is some additional error handling required in my code?