[Python-bugs-list] [ python-Bugs-417845 ] Python 2.1: SocketServer.ThreadingMixIn

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Bugs item #417845, was updated on 2001-04-21 08:28
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Category: Python Library
Group: None
Status: Open
Resolution: None
Priority: 5
Submitted By: Nobody/Anonymous (nobody)
Assigned to: Guido van Rossum (gvanrossum)
Summary: Python 2.1: SocketServer.ThreadingMixIn

Initial Comment:
SocketServer.ThreadingMixIn does not work properly
since it tries to close the socket of a request two
times.

Workaround for using SocketServer.ThreadingMixIn under
Python 2.1:

class MyThreadingHTTPServer(
  SocketServer.ThreadingMixIn,
  MyHTTPServer
):
  def close_request(self, request):
    pass



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Comment By: Jon Riehl (jriehl)
Date: 2001-05-01 14:20

Message:
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This is related to bug #419873.
The problem is not specifically in the ThreadingMixin
specifically, but where BaseServer calls close_request()
after calling process_request().  In the threading mixin,
process_request() spins the thread and returns, causing the
request socket to be invalidated while the thread is still
running.  The fix given above will keep the socket valid
while the thread is running, but may cause the socket to not
close properly (my threads generally close the socket when
they are done anyway.)

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Comment By: Luke Kenneth Casson Leighton (lkcl)
Date: 2001-04-26 05:41

Message:
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follow-up.  i took a look at the differences between
SocketServer.py
in 2.0 and 2.1.  there is one small change by guido to the
ThreadingMixIn.process_request() function that calls
self.server_close() instead of explicitly calling
self.socket.close(),
where TCPServer.server_close() calls self.socket.close().

if mr anonymous (hi!) has over-ridden server_close() and
explicitly closes the *request* socket, then of course the
socket will get closed twice.

the rest of the code-mods is a straightforward code-shuffle
moving code from TCPServer into BaseServer: from
examining the diff, i really don't see how bypassing
close_request(), as shown above with the Workaround
in the original bug-report, will help: that will in fact
cause the request _never_ to be closed!

the rest of this report is part of an email exchange with
guido, quoted here:

"the bug-report doesn't state whether python 2.0 worked and
2.1 didn't:
it also doesn't give enough info.

for all we know, he's calling close_request() himself or
request.close()
directly somewhere in his code, and hasn't told anybody,
which
is why he has to over-ride close_request() and tell it to do
nothing.
or he's closing the socket in the HandlerClass, in finish(),
or
something.

we just don't know.

either that, or his HandlerClass creates a socket once and
only
once, with the result that close_request() closes the one
socket, and he's _completely_ stuffed, then :)"



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Comment By: Luke Kenneth Casson Leighton (lkcl)
Date: 2001-04-26 04:11

Message:
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hi there,

i'm the person who wrote the BaseServer class.  guido
contacted me about it: could you please send me or post here
a working test example that demonstrates the problem.

i assume, but you do not state, that you have tested your
MyHTTPServer with python 2.0, please let us know, here, if
that is a correct assumption.

thanks!

luke

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