AW: keep-alive and vary in 304 responses

[Plüm , Rüdiger , Vodafone Group]

C2 General

> -----Ursprüngliche Nachricht-----
> Von: Yann Ylavic <ylavic....@gmail.com>
> Gesendet: Mittwoch, 10. April 2019 12:49
> An: httpd-dev <dev@httpd.apache.org>
> Betreff: Re: keep-alive and vary in 304 responses
> 
> On Wed, Apr 10, 2019 at 12:10 PM Stefan Eissing
> <stefan.eiss...@greenbytes.de> wrote:
> >
> > > Am 09.04.2019 um 18:48 schrieb Roy T. Fielding <field...@gbiv.com>:
> > >>
> > >> 2. Validation responses lose the "Vary" header from the
> unconditional response. This happens on resources where mod_deflate is
> active.
> > >>  The 200 response without any "if-modified-since" etc. carries
> "Vary: Accept-Encoding" as it should.
> > >>  The 304 response with "if-modified-since" has no "Vary" header.
> > >>  The code in mod_deflate looks as if it tries to add it in any
> case, where is it lost?
> > >
> > > That's one of many bugs related to design problems with mod_deflate.
> Basically,
> > > it chooses to insert itself into the response handling after the
> other checks are done,
> > > which means a 304 doesn't even know yet whether the response would
> use gzip.
> > > The solution (which I never found time to implement) is to replace
> dynamic gzip with
> > > a transfer encoding generator,
> 
> Do user-agents support "Transfer-Encoding: gzip, chunked" currently?
> That'd be the best/easier solution I think.

But TE is only hop-by-hop isn't it?. This would mean no e2e compression?
Also we need to keep in mind similar issues for similar filters e.g. mod_brotli

Regards

Rüdiger