Re: [EAI] Proposed resolution of List-* and downgrade- Issues

["Charles Lindsey" <chl at clerew.man.ac.uk>]

On Thu, 31 Jul 2008 16:44:35 +0100, Frank Ellermann  
<hmdmhdfmhdjmzdtjmzdtzktdkztdjz at gmail.com> wrote:

> Charles Lindsey wrote:
>
> > What we would want to write is
> >    Archived-At: <http://archive.mañana.com>
> > which is an IRI (using UTF-8, as always with IRIs)
>
> JFTR, s/as always with IRIs/as always with EAI/
>
> EAI always uses UTF-8, while IRIs can be in any charset
> determined by the context.  And for EAI that context is
> of course UTF-8.  But in a KOI8-R document it's KOI8-R:

Not quite. It the IRI appears in a document written in KO18-R, then:
1. You convert the KO18-R into unicode
2. You convert the unicode into UTF-8
3. You %-encode the UTF-8
4. Now you have the proper URI

Of course if the context is headers within a UTF8SMTP message, then steps  
1 and 2 are redundant.

> > which, upon conversion to a URI, would simply %-encode
> > that 'ñ'.
>
> For an <ipath>, <iquery>, or an <ifragment>.  But your
> example has the ñ in the <ihost>, and there you would
> use IDNA(bis) rules to convert this into an URL:
>
> Archived-At: <http://archive.xn--maana-pta.com/>

RFC 3987 says you MAY (possibily even SHOULD) convert to punycode in this  
case, but you also MAY just %-encode it and hope whatever comes next knows  
how to punycode it before doing any DNS lookup.

OTOH, IRIs are not currently allowed in the 'http' scheme, so it would  
need an explicit EAI extension (plus downgrade) to permit the Archived-At  
header field to use IRIs. Likewise for any List-* header fields.

Likewise for the 'mailto' scheme unless and until mailto-bis tells us  
otherwise. I think we really need Martin to publish a mailto-bis draft  
before we can proceed much further with List-* headers.

> Mailto-bis IRIs on a KOI8-R page would be interesting:
>
> If they are transformed to UTF-8 (the first step in a
> IRI to URI conversion) they might work with EAI UTF-8.

The rule is clear that you first apply the 4 steps I gave above. before  
you try interpreting them further.

--
Charles H. Lindsey ---------At Home, doing my own thing------------------------
Tel: +44 161 436 6131                       
   Web: http://www.cs.man.ac.uk/~chl
Email: chl at clerew.man.ac.uk      Snail: 5 Clerewood Ave, CHEADLE, SK8 3JU, U.K.
PGP: 2C15F1A9      Fingerprint: 73 6D C2 51 93 A0 01 E7 65 E8 64 7E 14 A4 AB A5
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