Re: Multiple header fields with the same field name - unwritten assumption about quoted commas in values?

Bjoern Hoehrmann <derhoermi@gmx.net> Tue, 15 January 2013 18:35 UTC

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From: Bjoern Hoehrmann <derhoermi@gmx.net>
To: Karl Dubost <karld@opera.com>
Cc: Julian Reschke <julian.reschke@gmx.de>, Piotr Dobrogost <p@ietf.dobrogost.net>, ietf-http-wg@w3.org
Date: Tue, 15 Jan 2013 19:33:09 +0100
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Subject: Re: Multiple header fields with the same field name - unwritten assumption about quoted commas in values?
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* Karl Dubost wrote:
>Le 16 janv. 2013 à 00:30, Julian Reschke a écrit :
>> Note: current text in editor's copy is:
>> 
>> "A sender MUST NOT generate multiple header fields with the same field 
>> name in a message unless either the entire field value for that header 
>> field is defined as a comma-separated list [i.e., #(values)] or the 
>> header field is a well-known exception (as noted below)." -- 
>> <http://greenbytes.de/tech/webdav/draft-ietf-httpbis-p1-messaging-latest.html#rfc.section.3.2.2>
>
>but then to my earlier message, Bjoern replied:
>
>Le 10 janv. 2013 à 00:59, Bjoern Hoehrmann a écrit :
>> The Link header appears to be defined as taking a comma-separated list,
>> <http://tools.ietf.org/html/rfc5988#section-5>, so the "MUST NOT" above does not apply to the Link header.
>
>and it seems to contradict my understanding.

The structure of the sentence above is "MUST NOT $z UNLESS $a OR $b".
Take it as "MUST NOT <play video games> UNLESS <completed chores> OR
<no school tomorrow>". When <no school tomorrow> then this does not
say anything about <play video games>. Same when <completed chores>.
When you are caught at <play video games> while neither <no school
tomorrow> nor <completed chores> however, then that's non-compliant.
The Link header is a case of <completed chores>.
-- 
Björn Höhrmann · mailto:bjoern@hoehrmann.de · http://bjoern.hoehrmann.de
Am Badedeich 7 · Telefon: +49(0)160/4415681 · http://www.bjoernsworld.de
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