[Python-ideas] PEP 3156: getting the socket or peer name from the transport

[Guido van Rossum]

On Sun, Jan 27, 2013 at 4:16 AM, Antoine Pitrou <solipsis at pitrou.net> wrote:
> Le dimanche 27 janvier 2013 à 14:12 +0200, Yuval Greenfield a écrit :
>> On Sun, Jan 27, 2013 at 1:21 PM, Antoine Pitrou <solipsis at pitrou.net>
>> wrote:
>>         > Most protocols should be written independent of transport.
>>         But it seems to
>>         > me that a user might write an entire app as a "protocol".
>>
>>
>>         Well, such an assumption can fall flat. For example,
>>         certificate
>>         checking in HTTPS expects that the transport is some version
>>         of TLS or
>>         SSL: http://tools.ietf.org/html/rfc2818.html#section-3.1
>>
>>
>> I'm not sure I understood your reply. You'd be for an api that exposes
>> the underlying transport? I meant to say that "an entire app" entails
>> control over the subtleties of the underlying transport.
>
> What I meant is that the HTTP protocol needs to know that it is running
> over a secure transport, and it needs to fetch the server certificate
> from that transport (or, alternatively, it needs to have one of its
> callbacks called by the transport when the certificate is known). That's
> not entirely transport-agnostic.

Yeah, it sounds like in the end having access to the socket itself (if
there is one) may be necessary. I suppose there are a number of
different ways to handle that specific use case, but it seems clear
that we can't anticipate all use cases. I'd rather have a simpler
abstraction with an escape hatch than attempting to codify more use
cases into the abstraction. We can always iterate on the design after
Python 3.4, if there's a useful generalization we didn't anticipate.

-- 
--Guido van Rossum (python.org/~guido)