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Re: image/svg+xml, was: Feedback on Internet Media Types and the Web

From: Julian Reschke <julian.reschke@gmx.de>
Date: Thu, 18 Nov 2010 20:12:21 +0100
Message-ID: <4CE57A95.701@gmx.de>
To: "Henry S. Thompson" <ht@inf.ed.ac.uk>
CC: Chris Lilley <chris@w3.org>, Noah Mendelsohn <nrm@arcanedomain.com>, Henri Sivonen <hsivonen@iki.fi>, Larry Masinter <LMM@acm.org>, "www-tag@w3.org WG" <www-tag@w3.org>, MURATA Makoto <eb2m-mrt@asahi-net.or.jp>, Mark Nottingham <mnot@pobox.com>, alexey.melnikov@isode.com
On 18.11.2010 20:01, Henry S. Thompson wrote:
> ...
>> That's no problem.
>> However it *is* a problem to claim that .svgz files have the type
>> "image/svg+xml". They don't. Feed them into a recipient that expects
>> XML and see it fail.
> 'claim'?  Claim how?  Who has claimed this?  How might someone claim
> this in any substantive way, except by failing to include the above
> Content-Encoding header in a message containing a gzipped SVG
> document. . .

The media type registration claims it. If that's not the intent, can we 
please clarify it?

> OK, I've now followed the link [1] in your original message, and it
> seems very odd to me.  The passage Mark Nottingham quotes, modulo the
> correction of Content-Transfer-Encoding to Content-Encoding, seems
> entirely satisfactory to me.  What is the Content-Encoding header [2]
> _for_, if not precisely for this case:
>   "The Content-Encoding entity-header field is used as a modifier to
>    the media-type. When present, its value indicates what additional
>    content codings have been applied to the entity-body, and thus what
>    decoding mechanisms must be applied in order to obtain the
>    media-type referenced by the Content-Type header field."

Yes. That is true for *any* media type, so it's totally unclear why it 
needs to be repeated.

The registration for SVH however says that it's ok to sniff:

"In addition, gzip compressed content is readily recognised by the
initial byte sequence as described in [RFC1952] section 2.3.1."

That's at least how I read it.

> I've included Mark and Alexey in this conversation --- Alexey, I think
> we particularly need to hear from you about what is wrong with a
> message with the headers quoted above.
> ...

I recommend that we have this conversation on the media types mailing list.

Best regards, Julian
Received on Thursday, 18 November 2010 19:13:04 UTC

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