W3C home > Mailing lists > Public > public-credentials@w3.org > October 2015

Re: http signature and WebID

From: <henry.story@bblfish.net>
Date: Wed, 14 Oct 2015 22:30:43 +0100
Cc: W3C Credentials Community Group <public-credentials@w3.org>, public-webid <public-webid@w3.org>
Message-Id: <2EC99A17-1F57-4648-B59C-7AE496D57E49@bblfish.net>
To: Manu Sporny <msporny@digitalbazaar.com>

> On 14 Oct 2015, at 04:06, Manu Sporny <msporny@digitalbazaar.com> wrote:
> 
>> 
>> • Headers maintenance over transport:
>> 
>> 'If there are multiple instances of the same header field, all
>> header field values associated with the header field MUST be
>> concatenated, separated by a ASCII comma and an ASCII space `, `, and
>> used in the order in which they will appear in the transmitted HTTP
>> message.'
>> 
>> - what is the chance that proxies actually somehow reorder or add 
>> headers to a message sent?
> 
> Proxies do stuff like this on a regular basis.
> 
>> Is there an RFC that actually states this should not be done?
> 
> Not that I know of, no. Even if there was one, there is plenty of
> evidence that proxies rewrite headers.

I found the following in http://www.w3.org/Protocols/rfc2616/rfc2616.txt 

   The order in which header fields with differing field names are
   received is not significant. 
   
and a bit later

   The order in which header fields with the same
   field-name are received is therefore significant to the
   interpretation of the combined field value, and thus a proxy MUST NOT
   change the order of these field values when a message is forwarded.

So it looks like header order can be relied on. What I suppose may still
happen is a proxy add a new header of the same field name... 

Perhaps one can refer to that passage in the RFC to substantiate the decision.
( I was thinking otherwise that one could organise the headers alphabetically )

Henry
Received on Wednesday, 14 October 2015 21:31:14 UTC

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