The server in the wsgiref module is actually used a lot. For example, it is the server Django uses for development.A very common thing that happens during Django development is that the web browser closes the connection for some reason. Then very long stack traces appear in the Django logs:    [30/Aug/2018 12:10:38] "POST /login/ HTTP/1.1" 200 3964    Traceback (most recent call last):      File "d:\python37\Lib\wsgiref\handlers.py", line 138, in run        self.finish_response()      File "d:\python37\Lib\wsgiref\handlers.py", line 180, in finish_response        self.write(data)      File "d:\python37\Lib\wsgiref\handlers.py", line 274, in write        self.send_headers()      File "d:\python37\Lib\wsgiref\handlers.py", line 332, in send_headers        self.send_preamble()      File "d:\python37\Lib\wsgiref\handlers.py", line 255, in send_preamble        ('Date: %s\r\n' % format_date_time(time.time())).encode('iso-8859-1')      File "d:\python37\Lib\wsgiref\handlers.py", line 453, in _write        result = self.stdout.write(data)      File "d:\python37\Lib\socketserver.py", line 796, in write        self._sock.sendall(b)    ConnectionAbortedError: [WinError 10053] An established connection was aborted by the software in your host machine    [30/Aug/2018 12:10:38] "POST /login/ HTTP/1.1" 500 59    ----------------------------------------    Exception happened during processing of request from ('127.0.0.1', 50112)    Traceback (most recent call last):      File "d:\python37\Lib\wsgiref\handlers.py", line 138, in run        self.finish_response()      File "d:\python37\Lib\wsgiref\handlers.py", line 180, in finish_response        self.write(data)      File "d:\python37\Lib\wsgiref\handlers.py", line 274, in write        self.send_headers()      File "d:\python37\Lib\wsgiref\handlers.py", line 332, in send_headers        self.send_preamble()      File "d:\python37\Lib\wsgiref\handlers.py", line 255, in send_preamble        ('Date: %s\r\n' % format_date_time(time.time())).encode('iso-8859-1')      File "d:\python37\Lib\wsgiref\handlers.py", line 453, in _write        result = self.stdout.write(data)      File "d:\python37\Lib\socketserver.py", line 796, in write        self._sock.sendall(b)    ConnectionAbortedError: [WinError 10053] An established connection was aborted by the software in your host machine    During handling of the above exception, another exception occurred:    Traceback (most recent call last):      File "d:\python37\Lib\wsgiref\handlers.py", line 141, in run        self.handle_error()      File "D:\Virtualenvs\ledev-X6wd5Q8f\lib\site-packages\django\core\servers\basehttp.py", line 86, in handle_error        super().handle_error()      File "d:\python37\Lib\wsgiref\handlers.py", line 368, in handle_error        self.finish_response()      File "d:\python37\Lib\wsgiref\handlers.py", line 180, in finish_response        self.write(data)      File "d:\python37\Lib\wsgiref\handlers.py", line 274, in write        self.send_headers()      File "d:\python37\Lib\wsgiref\handlers.py", line 331, in send_headers        if not self.origin_server or self.client_is_modern():      File "d:\python37\Lib\wsgiref\handlers.py", line 344, in client_is_modern        return self.environ['SERVER_PROTOCOL'].upper() != 'HTTP/0.9'    TypeError: 'NoneType' object is not subscriptable    During handling of the above exception, another exception occurred:    Traceback (most recent call last):      File "d:\python37\Lib\socketserver.py", line 647, in process_request_thread        self.finish_request(request, client_address)      File "d:\python37\Lib\socketserver.py", line 357, in finish_request        self.RequestHandlerClass(request, client_address, self)      File "d:\python37\Lib\socketserver.py", line 717, in __init__        self.handle()      File "D:\Virtualenvs\ledev-X6wd5Q8f\lib\site-packages\django\core\servers\basehttp.py", line 154, in handle        handler.run(self.server.get_app())      File "d:\python37\Lib\wsgiref\handlers.py", line 144, in run        self.close()      File "d:\python37\Lib\wsgiref\simple_server.py", line 35, in close        self.status.split(' ',1)[0], self.bytes_sent    AttributeError: 'NoneType' object has no attribute 'split'    ----------------------------------------Obviously, this is a bit annoying when developing with Django daily. Since Django simply uses the wsgiref server, I though the best solution was to handle closed connections more gracefully there.I think the best solution is to simply add another except clause here:https://github.com/python/cpython/blob/e6dac0077996b1e1f886f036d6f2606237fa4c85/Lib/wsgiref/handlers.py#L142 . We should catch ConnectionAbortedError here and return from the function.I am happy to create a PR if this is what we want to do.

Thanks for the report and PR. I think this is the same asissue27682. I noticed the same during running `make serve` locally for documentation and it's worth fixing. I am just wondering if it makes sense to fix the TypeError and AttributeError too. Also I couldn't see any tests for this and I don't know if it's possible to test this scenario.I will leave it to the reviewer to close this and raise PR againstissue27682 or continue discussion here.Thanks again!

Closing this as a duplicate. Please carry over toissue 27682 any PR's that are still current.