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Re: Review of Content-Encoding: value token

From: Julian Reschke <julian.reschke@gmx.de>
Date: Tue, 03 Feb 2009 11:30:05 +0100
Message-ID: <49881CAD.30906@gmx.de>
To: Mark Nottingham <mnot@mnot.net>
CC: "Roy T. Fielding" <fielding@gbiv.com>, Carine Bournez <carine@w3.org>, ietf-http-wg@w3.org

Mark Nottingham wrote:
> 
> Well, if we leave the text how it is, it will have that effect...
> ...

Clarifying: I do agree that using Content-Encoding for encodings that 
are lossy on the octet stream level probably is a bad idea.

And yes, implementations that introduce content codings need to make 
sure that outgoing (Etag:) and incoming etags (conditional headers) are 
transformed correctly. If that's not yet clear enough in the spec, we 
should improve it.

That being said, the current spec text about Content Codings says:

"Content coding values indicate an encoding transformation that has been 
or can be applied to an entity. Content codings are primarily used to 
allow a document to be compressed or otherwise usefully transformed 
without losing the identity of its underlying media type and without 
loss of information." -- 
<http://greenbytes.de/tech/webdav/draft-ietf-httpbis-p3-payload-05.html#rfc.section.3.2>

I can see that in this case (when encoding an XML document in a new 
binary encoding), some people will argue that indeed there is no loss of 
information.

So,

- is it allowed (do not change the spec), or

- is it allowed, but considered a bad idea (add a note to the spec?), or

- it it disallows (clarify the spec to speak about octet-by-octet identity).

BR, Julian
Received on Tuesday, 3 February 2009 10:30:54 GMT

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