[Python-Dev] Accepting PEP 3154 for 3.4?

Tim Peters tim.peters at gmail.com
Wed Nov 20 23:37:28 CET 2013

>> BTW, I'm not a web guy:  in what way is HTTP chunked transfer mode
>> viewed as being flawed?  Everything I ever read about it seemed to
>> think it was A Good Idea.

> It just didn't work for some time, see e.g.
> http://bugs.python.org/issue1486335
> http://bugs.python.org/issue1966
> http://bugs.python.org/issue1312980
> http://bugs.python.org/issue3761
> It's not that the protocol was underspecified - just the implementation
> was "brittle" (if I understand that word correctly).

"Easily broken in catastrophic ways" is close, like a chunk of peanut
brittle can shatter into a gazillion pieces if you drop it on the


Or like the infinite loops in some of the bug reports, "just because"
some server screwed up the protocol a little at EOF.

But for pickling there are a lot fewer picklers than HTML transport
creators ;-)  So I'm not much worried about that.  Another of the bug
reports amounted just to that urllib, at first, didn't support chunked
transfer mode at all.

> And I believe (and agree with you) that the cause for this "difficult
> to implement" property is that the framing is in putting framing "in the middle"
> of the stack (i.e. not really *below* pickle itself, but into pickle
> but below the opcodes - just like http chunked transfer is "in" http,
> but below the content encoding).

It's certainly messy that way.  But doable, and I expect the people
working on it are more than capable enough to get it right, by at
latest the 4th try ;-)

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