I ran into this issue during my testing of django-channels and daphne (but the issue is not exclusive to them).
--- <exception caught here> ---
File "/Users/****/lib/python3.6/site-packages/twisted/internet/base.py", line 896, in runUntilCurrent
call.func(*call.args, **call.kw)
File "/Users/****/lib/python3.6/site-packages/twisted/web/http.py", line 2288, in forceAbortClient
self.transport.abortConnection()
File "/Users/****/lib/python3.6/site-packages/twisted/protocols/tls.py", line 435, in abortConnection
self._shutdownTLS()
File "/Users/****/lib/python3.6/site-packages/twisted/protocols/tls.py", line 338, in _shutdownTLS
shutdownSuccess = self._tlsConnection.shutdown()
builtins.AttributeError: 'NoneType' object has no attribute 'shutdown'
This is only the case when HTTP/2 is in use. HTTP1.1 works fine and I've never had an issue like this. I've done a bit of investigating and I've noticed that self._tlsConnection.shutdown() is called 2x, once when the timeout is exceeded and self._tlsConnection is set to None, then again for some unknown reason. I'm not knowledgeable enough in HTTP standards to know if this is expected behavior. Am I doing something wrong or is this a bug?
How to reproduce
Install Twisted with HTTP/2 and TLS support
pip install -U twisted[http2,tls]
Create TLS certificates
openssl genrsa -aes256 -passout pass:SuperSecretPassword -out server.key 2048
openssl req -new -key server.key -passin pass:SuperSecretPassword -out server.csr
openssl x509 -req -passin pass:SuperSecretPassword -days 1024 -in server.csr -signkey server.key -out server.crt
openssl rsa -in server.key -out server_no_pass.key -passin pass:SuperSecretPassword
mv server_no_pass.key server.key
Create a simple TLS server (it's not django-channels, it's klein, because this issue isn't exclusive to channels). This will start a server on https://0.0.0.0:9999
from klein import route, run
@route('/')
def hello(request):
return 'hello'
run(endpoint_description='ssl:9999:interface=0.0.0.0:certKey=server.crt:privateKey=server.key')
On a web browser, go to https://localhost:9999. Open the developer tools and navigate to network tab. Enable the protocol option and ensure it's HTTP/2.0. I've tested on both Chrome and Firefox.
Wait a few minutes and the server will hit the traceback.
