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X-Device-xxx header: final name and use?

From: Francois Daoust <fd@w3.org>
Date: Mon, 26 May 2008 16:48:12 +0200
Message-ID: <483ACDAC.50700@w3.org>
To: public-bpwg-ct <public-bpwg-ct@w3.org>

For 4.1.4 "Altering Header Values", we've left the resolution on the 
actual name of the header for later on.
Later on is now!

Trying to summarize different positions heard before we published the 
doc as First Public Working Draft:

1. X-Device-<original header name> is used in practice

2. Device is probably not the best name we could think of. X-Received, 
X-Original, in short everything else than "Device" is probably better.

3. There could be a potential conflict with existing X- headers used by 
some applications, and we'd rather choose a name that surely is not used 
anywhere else: X-CT-Received for instance. Note that in all cases, we 
cannot "register" the header as it's an experimental one.

4. What is the CT-proxy supposed to do when it receives an 
X-Device-<some header name> HTTP header?

Did I forget something?

My personal short contribution on that:
a) I'd go for the X-Device-<original header name> header on the grounds 
that it's already being used
b) I'd say that conflicts would probably have already arisen with the 
X-Device header. Unless anyone is aware of such a conflict, I'd say 
we're fine on the uniqueness of the name.
c) I don't quite see how we can solve 4 easily and in a satisfactory 
way, unless we are able to identify the proxy that altered the headers 
(which in turn makes things slightly too complex to my taste), or unless 
we say:
"If the request includes a X-Device-[whatever] header, the proxy MUST 
NOT apply further alteration", which would be symmetric to what we 
already have in 4.4 for the response with the Warning header. Any other 

Received on Monday, 26 May 2008 14:48:45 UTC

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