[Python-Dev] SocketServer and UserDict patches

[Ka-Ping Yee]

On Tue, 10 Apr 2001, Guido van Rossum wrote:
> > 1.  UserDict.get(), .update(), and .setdefault()
[...]
> I agree with the gist of this -- it should have been done the way you
> propose.
[...]
> But can you guarantee that fixing this so late in the release cycle
> won't break anybody's code?

Right, obviously i can't.  Here are some thoughts:
(Nonetheless i do agree it's a bit late to notice this.)

    1.  All the standard tests pass with this change (though
        of course that's a small sample).

    2.  It's hard to imagine someone's code depending on this
        particular bug (i think i can justify calling it a bug).
        Anyone who wrote a UserDict-derived class that actually
        intended to use "get" most likely had to work around it
        anyway, to get any reasonable sort of result.

    3.  Would you consider allowing the addition of a get()
        method just to cgi.SvFormContentDict to fix its behaviour?
        (The broken get() behaviour was present for this particular
        class in 2.0 but not in 1.5.2.)


> > 2.  SocketServer.StreamRequestHandler
[...]
> I don't think this is the right solution.  A principle I like very
> much to keep my head clear about closing files is "whoever opens it
> closes it".  The request/connection socket is created by a different
> class, so should really be closed there.

Good point.  How about adding to BaseServer.handle_request instead?

    def handle_request(self):
        """Handle one request, possibly blocking."""
        try:
            request, client_address = self.get_request()
        except socket.error:
            return
        if self.verify_request(request, client_address):
            try:
                self.process_request(request, client_address)
            except:
                self.handle_error(request, client_address)
  +     request.close()

I forgot to mention that this is a testable and observable fix
(Netscape gets stuck in Linux and IE gets stuck in Win2K without
the fix, and both work properly when i make this fix.)

Note that this makes explicit the division of responsibilities
that, if the request handler wants to continue dealing with the
request connection after its constructor returns (as in the
case of the forking and threading variants), it must duplicate
its own copy of the file descriptor (which it already does).
I think this is good, as then each file descriptor can be
associated with a clear owner.


-- ?!ng

"Don't worry about people stealing an idea.  If it's original, you'll
have to jam it down their throats."
    -- Howard Aiken