I-D Action:draft-josefsson-getaddrinfo-idn-00.txt

[Simon Josefsson]

Nicolas Williams <Nicolas.Williams at oracle.com> writes:

> On Thu, Jun 17, 2010 at 10:12:41AM +0200, Simon Josefsson wrote:
>> Nicolas Williams <Nicolas.Williams at oracle.com> writes:
>> > Therefore I think that getaddrinfo() should support lookups by IDNs
>> > encoded in the caller's locale's codeset as described above, but should
>> > return A-labels unless a hint is given that U-labels are preferred.
>> 
>> In other words, you want AI_IDN to be the default behaviour, but not
>> AI_CANONIDN.
>
> Right.
>
>>               There likely needs to be an AI_NO_IDN or similar if an
>> application for some reason wants to disable IDN processing of inputs.
>
> Yes.
>
>> I'm not sure what a use-case for AI_NO_IDN would be, but I suspect there
>> may be some.
>
> There's no harm in having such a flag.

Great.  I'm thinking of updating my draft to specify this, and to make
it a bit less internal-memo-like.

> I also want a AI_NO_CANONIDN, in preparation for a future day when
> getaddrinfo() returns U-labels as the canonical hostname by default.

I'm not sure this day will come.  There will always be software
components that are written simplistically without IDNA support.  But
I'm not strongly against the flag.  The downside is that it adds
complexity with uncertain gain, something I generally prefer to avoid.

The AI_NO_CANONIDN flag could also be introduced later on, when we
actually consider making the change you suggest, and we may be in a more
informed situation to specify the flag more precisely at that point too.

/Simon