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Re: intermediaries, implicit gzip, etags, no-transform

From: Martin Nilsson <nilsson@opera.com>
Date: Fri, 20 Jun 2014 22:15:17 +0200
To: ietf-http-wg@w3.org
Message-ID: <op.xhrrvry3iw9drz@beryllium.oslo.osa>
On Fri, 20 Jun 2014 17:12:20 +0200, Julian Reschke <julian.reschke@gmx.de>  
wrote:

> Hi there,
>
> so I played around with Google's Data Compression proxy and Opera's  
> Turbo today, and found:
>
> - both implicitly use content-coding gzip, but do not touch the Etag,  
> potentially breaking HTTP semantics
>
> - GDCP adds a custom header field describing the original content length  
> (which of course has not been registered)
>
> - setting "cache-control: no-transform" on the response, does not change  
> this behavior, thus both seem to violate a "MUST NOT" requirement from  
> <http://greenbytes.de/tech/webdav/rfc7230.html#rfc.section.5.7.2>
>

Both GDC and Turbo communicates between endpoints of known  
implementations. MUST and MUST NOTs are really only relevant seen from the  
outside, i.e. beyond the proxy. The exception would be intermediaries  
looking at this traffic, which both protocols assumes there are none of.

The cache-control: no-transform is really only set on ad images, so it is  
the semantic equivalent to the high priority flag on emails.

The actual implementation of Turbo varies quite a lot between versions btw.

/Martin Nilsson

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Received on Friday, 20 June 2014 20:15:36 UTC

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