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From Alexei Kosut <>
Subject Re: proxying
Date Wed, 24 Jan 1996 07:51:51 GMT
On Tue, 23 Jan 1996, Brian Behlendorf wrote:

> Not true.  If you are paranoid about stale copies, use Proxy: no-cache.

Is this what they're calling it nowadays? Do note that this is not part of
HTTP/1.0 - the only cache-related code is the client's ability to send
Pragma: no-cache and bypass proxy caches. Which my module supports. But
nothing else. HTTP/1.1 has some proposals, but in case you haven't
noticed, the current HTTP/1.1 draft has, written across the top in big
letters, (loosely parphrasing) "this does not have the support of anyone,
and everyone hates it, and it'll all be changed, so don't even bother
reading it". 

> If you are less than paranoid and willing to trust proxies to adhere to 
> the HTTP 1.0 specification, then setting Expires: headers apppropriately 
> will get you what you want.  But since most servers don't have a user 
> interface for setting those headers, proxies are usually only left with a 
> Last-Modified header to deal with - the "recommended" action is to always 
> send an If-Modified-Since request, but some proxies allow the behavior to 
> be configurable.  The AOL caches, for example, always send IMS requests 
> for HTML documents, but cache GIF images for up to 6 hours (unless they 
> have a Proxy: no-cache).  

My proxy module, btw, always sends an If-modified-since in the absence of 
an Expires.

> I would definitely like to see some interface to setting Expires: headers 
> in Apache.  A heuristic like Alexei's is interesting, I'd want to cap it 

It's not mine, it's CERN's. Blame them :)

> at 48 hours or something.  An interface to compare which of the cache 

Well, as I said, I always send I-m-s, so no cap needed. I just use the 
heurestic to decide when to wipe it from the cache.

BTW, has anyone actually tried to use my module, as I uploaded it? There 
have been a lot of comments about proxying in general, but as of yet, no 
one has written to say "this sucks, it crashed my hard disk", or "are you 
out of your mind! this was a waste of download time" or even "heck, I've 
seen better code from Microsoft." Anyone?

--/ Alexei Kosut <> /--------/ Lefler on IRC
----------------------------/ <>
The viewpoints expressed above are entirely false, and in no way
represent Alexei Kosut nor any other person or entity. /--------------

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