Re: [Ietf-message-headers] Provisional registration of 5 X-Device-* HTTP Header fields for use in content transformation guidelines

Francois Daoust <> Tue, 04 August 2009 16:31 UTC

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Date: Tue, 04 Aug 2009 18:31:00 +0200
From: Francois Daoust <>
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Cc: Graham Klyne <>,
Subject: Re: [Ietf-message-headers] Provisional registration of 5 X-Device-* HTTP Header fields for use in content transformation guidelines
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Apologies for the late reply, I somehow managed not to see it up until now.

SM wrote:
> Hi Francois,
> At 08:34 10-07-2009, Francois Daoust wrote:
>> The situation the Mobile Web Best Practices working group is trying to 
>> address is one where different vendors used different HTTP header 
>> field conventions (all starting with 'X-') for the same use in their 
>> proxies, requiring content providers to support the different names 
>> when they wanted to do things properly. What the working group would 
>> like to do is to shrink the list of existing conventions to one and 
>> only one convention, but would prefer not to introduce any new 
>> convention (be it the last one) for that to happen. The 'X-Device-foo' 
>> format is the most commonly used format in the list based on the 
>> group's experience, and thus the chosen one.
> I'll encourage you to adopt Graham's suggestion of moving to 
> "Device-foo" or any other valid name that does not start with "X-".  
> These "X-" headers are generally for private use where the 
> interpretation is by private agreement.  There are people outside the 
> group that might use that header field for other purposes and they are 
> unlikely to look it up in the registry.  If your working group already 
> agrees on having one convention, it is better to do away with the "X-".

Thanks. I understand the suggestion and the implications of not 
following the suggestion.

At this point, the working group agrees on having one convention among 
the existing ones, which unfortunately all start with "X-". But the 
working group does not agree to do away with the "X-" not to introduce 
any kind of new notation. If you're fine with it, the group would thus 
like to proceed only with the registration of the "X-" versions of the 
HTTP header fields.