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RE: convert to punycode: SHOULD or MAY (was: RE: Are IDNs allowed in http IRIs?)

From: Martin Duerst <duerst@w3.org>
Date: Tue, 27 Apr 2004 13:17:02 +0900
Message-Id: <>
To: Larry Masinter <LMM@acm.org>, "'Michel Suignard'" <michelsu@windows.microsoft.com>, public-iri@w3.org

Hello Larry,

At 03:07 04/03/30 -0800, Larry Masinter wrote:

>I think this is an interoperability issue, and that neither SHOULD nor MAY
>are appropriate. Rather, there is a MUST with a couple of alternatives.
>resolving an IRI with non-ascii host names MUST use one of the established
>methods of resolving the host name correctly.

I think this is a very valid point. However, I think that this is
overall covered by the current spec. The spec has an overall MUST
for the general conversion procedure:

"Applications MUST map IRIs to URIs using the following two steps."

It then allows (MAY) an additional step in certain well-defined cases:

"Infrastructure accepting IRIs MAY convert the ireg-name
component of an IRI as follows (before step 2 above) for schemes
that are known to use domain names in ireg-name, but where the
scheme definition does not allow %-escaping for ireg-name:"

Finally, it recommends that the above additional step be taken
under certain conditions:

"This conversion SHOULD be used when the goal is to
maximize interoperability with legacy URI resolvers."

So it seems to me that this is covered. Of course, there is
always the question of whether other things, not discussed in
the spec, are allowed or not, but I think it is a general
principle when writing IETF specs to not include generalities
such as "Any other method than those discussed in this
document MUST NOT be used."

I hope this reply sufficiently addresses this issue
(punycodeSHOULD-23). I have noted this as tentatively closed.

Regards,     Martin.
Received on Tuesday, 27 April 2004 00:17:15 UTC

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