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Re: NEW ISSUE: repeating non-list-type-headers

From: Bjoern Hoehrmann <derhoermi@gmx.net>
Date: Tue, 20 Nov 2007 11:01:04 +0100
To: Julian Reschke <julian.reschke@gmx.de>
Cc: HTTP Working Group <ietf-http-wg@w3.org>
Message-ID: <2jb5k3hm1pt27burnelg6qsnd3p03pgq6r@hive.bjoern.hoehrmann.de>

E* Julian Reschke wrote:
>We currently say in Section 4.2:
>
>    Multiple message-header fields with the same field-name MAY be
>    present in a message if and only if the entire field-value for that
>    header field is defined as a comma-separated list [i.e., #(values)].
>
>-- <http://tools.ietf.org/html/rfc2616#section-4.2>
>
>Now this seems to be kind of backwards, wouldn't it be *much* clearer if 
>it said:
>
>    Multiple message-header fields with the same field-name MUST NOT be
>    present in a message unless the entire field-value for that
>    header field is defined as a comma-separated list [i.e., #(values)].

No, unlike the old text, that does not say when you may use them.

>That being said, do we have a recommendation for recipients when that 
>requirement is violated? I would assume that servers SHOULD return a 400 
>(Bad Request), but what about clients?

You fold them into a single value as the specification suggests unless
there is some reason not to do that. Servers should not be required to
respond with Bad Request, they might not know the header, and they
should not treat

  X: a
  X: b

differently from X:a,b, so if they don't give you a Bad Request for the
latter, they should not do it for the former. I think the current text
is fine.
-- 
Björn Höhrmann · mailto:bjoern@hoehrmann.de · http://bjoern.hoehrmann.de
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Received on Tuesday, 20 November 2007 10:01:17 GMT

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