From: Charles Lindsey (chl@clw.cs.man.ac.uk)
Date: Wed Sep 25 2002 - 19:56:57 CDT
In <yl3cs7ez5v.fsf@windlord.stanford.edu> Russ Allbery <rra@stanford.edu> writes:
>Charles Lindsey <chl@clw.cs.man.ac.uk> writes:
>> OK, so you want to disallow all usage of UTF-8 in Netnews headers in
>> favour of requiring them all to be encoded within 7bits?
>I don't think I would say that.
>However, I would only allow 8-bit characters in netnews headers in places
>where it's not going to break something else, and whether the places where
>it's actually safe ends up being the null set isn't something that I've
>seen established yet.
In the cases where there is the possibility of using RFC 2047/2231, it is
always safe because the implementor of the posting agent can make the
necessary arrangements. If he chooses to encode every time, then that is
fine. If he chooses to stick with UTF-8 wherever possible, that is fine
too.
The only two cases known to cause difficulty are User-Agent (which I am
sure can be fixed) and Newsgroups. And the point with Newsgroups is that
whatever we decide now will be fixed FOR EVER (since it has to be a
canonical form on the wire, and it will be impossible to change to a
different canonical form later on).
In 20 years time (and possibly in 2 years time), any canonical form that
still tries to cram 8bit codes into 7bits is going to look totally and
utterly stupid. Which is why we should invest in a little extra
complication now in order to have a clean system in the long term.
>I certainly don't think that it's sane to have to worry about headers
>contained in nested multiparts; there are reasons why the MIME standards
>require what they require.
I don't think you have to worry about those if you are prepared to take a
pragmatic (as opposed to a legalistic) view of what actually works on the
existing mail transport system. You already said earlier that you would
consider detecting the octets in the range 0x80-9f and only encode in
those cases.
-- Charles H. Lindsey ---------At Home, doing my own thing------------------------ Tel: +44 161 436 6131 Fax: +44 161 436 6133 Web: http://www.cs.man.ac.uk/~chl Email: chl@clw.cs.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