Re: Require UAs and intermediary caches to assume Vary: User-Agent

My point was that in most cases it is only the text that varies.

While there is prior art for varied images back to 1993, this is still very
rare. A site may send links to different static content depending on who is
accessing the site but I suspect that the case where the image returned
from a URL changes is negligible.



On Wed, Oct 17, 2012 at 5:03 PM, Amos Jeffries <squid3@treenet.co.nz> wrote:

> On 18.10.2012 00:30, Phillip Hallam-Baker wrote:
>
>> How much of the Web actually passes through client side proxies these
>> days?
>> Of those, how many have  caches?
>>
>>
> Unknown, but still a large enough portion of the population to matter.
>
> There are still countries like .au and .nz which have very high
> international transit costs or low bandwidth using large proxy farms in the
> major telecos. The historical reasons for caching have not disappeared, the
> bandwidth increases these late few decades have just spoilt the user base
> and added to the need if anything. Educational institutions and corporate
> sites are also still using proxies a lot as gateway control servers.
>
> Ubuntu and Debian provide software install counters and inform me there
> are over half a million Squid, Varnish, HAproxy, polipo, oos still
> installed and running around the world - thats anything up to 500 M users
> right there. Other more popular distros, other proxies, unreported installs
> - who knows how big the total actually is.
>
>
>
>  There was a good reason for caching proxies in 1993. I don't see much
>> justification or utility in fiddling with that part of the spec now. The
>> content that is relevant for caching these days is huge chunks of video,
>> audio and images, the part that is generated is text.
>>
>
> With most of user generated www traffic being videos and media the case
> for caching those still stands and is gaining popularity amongst sysadmin.
>
> AYJ
>
>
>


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