uvicorn: Exception in ASGI application - 'NoneType' object is not subscriptable

Hello, I have ‘NoneType’ error on asgi_send method, im not sure for why this happens:

[2018-11-07 22:13:39 -0500] [2868] [ERROR] Exception in ASGI application
Traceback (most recent call last):
  File "/usr/local/lib/python3.6/dist-packages/uvicorn/protocols/websockets/websockets_impl.py", line 140, in run_asgi
    result = await asgi(self.asgi_receive, self.asgi_send)
  File "/usr/local/lib/python3.6/dist-packages/channels/sessions.py", line 175, in __call__
    return await self.inner(receive, self.send)
  File "/usr/local/lib/python3.6/dist-packages/channels/middleware.py", line 41, in coroutine_call
    await inner_instance(receive, send)
  File "/usr/local/lib/python3.6/dist-packages/channels/consumer.py", line 54, in __call__
    await await_many_dispatch([receive, self.channel_receive], self.dispatch)
  File "/usr/local/lib/python3.6/dist-packages/channels/utils.py", line 50, in await_many_dispatch
    await dispatch(result)
  File "/usr/local/lib/python3.6/dist-packages/channels/consumer.py", line 67, in dispatch
    await handler(message)
  File "/usr/local/lib/python3.6/dist-packages/channels/generic/websocket.py", line 173, in websocket_connect
    await self.connect()
  File "/home/deploy/xxxxxx/app/consumers.py", line 314, in connect
    await self.accept()
  File "/usr/local/lib/python3.6/dist-packages/channels/generic/websocket.py", line 186, in accept
    await super().send({"type": "websocket.accept", "subprotocol": subprotocol})
  File "/usr/local/lib/python3.6/dist-packages/channels/consumer.py", line 75, in send
    await self.base_send(message)
  File "/usr/local/lib/python3.6/dist-packages/channels/sessions.py", line 226, in send
    return await self.real_send(message)
  File "/usr/local/lib/python3.6/dist-packages/uvicorn/protocols/websockets/websockets_impl.py", line 170, in asgi_send
    self.scope["server"][0],
TypeError: 'NoneType' object is not subscriptable

Any ideas?

Django==2.1.3 channels==2.1.5 channels_redis==2.3.1 gunicorn==19.9.0 uvicorn==0.3.20

About this issue

Original URL
State: closed
Created 6 years ago
Comments: 15 (11 by maintainers)

Commits related to this issue

Fixes bug #242, Exception in ASGI application - 'NoneType' object is not subscriptable, server is not defined in scope — committed to agronick/uvicorn by agronick 6 years ago
Revert "Fixes bug #242, Exception in ASGI application - 'NoneType' object is not subscriptable, server is not defined in scope" This reverts commit fdea7ff0463bb0b6bcad60497ffa08264fced4ea. — committed to agronick/uvicorn by agronick 5 years ago
Only set text_data or bytes_data but not both (#349) * Fixes bug #242, Exception in ASGI application - 'NoneType' object is not subscriptable, server is not defined in scope * Only set text or byt... — committed to encode/uvicorn by agronick 5 years ago

Most upvoted comments

Its really easy to see how this is happening. get_local_addr(transport) returns None if the sockname key is not set. You just follow that code to where it gets set on the scope and its taking [0] from None. What should that function return when sockname is not set (it appears to never be set) instead of None?

agronick on Dec 6, 2018

This issue is very easy to produce and very easy to fix. Happens out of the box with latest version and prevents websockets from working.

It comes from protocol/utils.py in this method

def get_local_addr(transport):
    info = transport.get_extra_info("sockname")
    if info is not None and isinstance(info, (list, tuple)) and len(info) == 2:
        return (str(info[0]), int(info[1]))
    return None

If you change it to return ['', 0] the problem goes away. This method directly populates the scope’s server variable. As far as I can tell the variable sockname does not appear in anywhere in Uvicorn or Gunicorn.

agronick on Nov 30, 2018