[issue12498] asyncore.dispatcher_with_send, disconnection problem + miss-conception

[Xavier de Gaye]

Xavier de Gaye <xdegaye at gmail.com> added the comment:

> Actually the class asyncore.dispatcher_with_send do not handle
> properly disconnection. When the endpoint shutdown his sending part
> of the socket, but keep the socket open in reading, the current
> implementation of dispatcher_with_send will close the socket without
> sending pending data.
>
> Adding this method to the class fix the problem:
>
>     def handle_close(self):
>         if not self.writable():
>             dispatcher.close()


This does not seem to work. The attached Python 3.2 script
'asyncore_12498.py' goes into an infinite loop of calls to
handle_read/handle_close when handle_close is defined as above. In
this script the Writer sends a 4096 bytes message when connected, the
Reader reads only 64 bytes and closes the connection afterwards. Then
follows the sequence:

    select() returns a read event handled by handle_read()
    handle_read() calls recv()
    socket.recv() returns 0 to indicate a closed connection
    recv() calls handle_close

This sequence is repeated forever in asyncore.loop() since out_buffer
is never empty.

Note that after the first 'handle_close' has been printed, there are
no 'handle_write' printed, which indicates that the operating system
(here linux) states that the socket is not writable.

----------
nosy: +xdegaye
Added file: http://bugs.python.org/file23547/asyncore_12498.py

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<http://bugs.python.org/issue12498>
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