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Re: Should the UTF-8 BOM trump overriding via HTTP or by users?

From: Bjoern Hoehrmann <derhoermi@gmx.net>
Date: Tue, 07 Jun 2011 06:39:34 +0200
To: Leif Halvard Silli <xn--mlform-iua@xn--mlform-iua.no>
Cc: www-international <www-international@w3.org>
Message-ID: <ua9ru6du286vkm8is0bhhvtreiui5kl78s@hive.bjoern.hoehrmann.de>
* Leif Halvard Silli wrote:
>Subject: Should the UTF-8 BOM trump overriding via HTTP or by users?

Higher-level information overrides lower-level information, explicit
information overrides fallbacks, and user agents should do what their
users want them to do. So, HTTP-level Content-Type overrides document-
internal information, a BOM overrides user-chosen fallbacks, and user-
chosen overrides trump anything else.

If you want X and your "agent" does Y against your wishes, then it's
not really an agent acting on your behalf, I don't think that point
merits any discussion at all. Similarily, for fallbacks, there is no
other way this could work due to the semantics of "fallback".

That leaves the BOM versus Content-Type. If you let the BOM override
the Content-Type header, it would be impossible to send content that
starts with something that looks like a BOM but really isn't over the
protocol. "Content-Type overrides BOM" is a "If X then Y" situation.

The other way around you get "If X then Y except when also A, then B,
ohh, and not X but Z then C, and..." as you've made the process de-
pendant on the internet media type.

Anyone who wants the BOM to take precedence over the HTTP Content-Type
header, or the charset parameter within it, is welcome to make an I-D
to that effect that updates RFC 2616 and RFC 4288 and possibly others.
Trying to sneak in such changes through backdoors is unacceptable. So,
if "HTML5" has rules as you suggest, that is most likely an error.
-- 
Björn Höhrmann · mailto:bjoern@hoehrmann.de · http://bjoern.hoehrmann.de
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Received on Tuesday, 7 June 2011 04:40:01 GMT

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