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From Alexei Kosut <>
Subject Re: cache verification
Date Mon, 04 Mar 1996 22:04:32 GMT
On Mon, 4 Mar 1996, David Robinson wrote:

> How does this differ from the current behaviour, and when is it better?

Currently, your proxy server gets a document, then caches it. If it gets 
another request for the document, and the Expires: date on the cached 
document (either explicit or implicit) has not passed, it returns the 
cached copy. As I've pointed out before, this is very often not the 
desired behavior. The desired behavior in many cases is to always send a
conditional GET request to the origin server and check to see if the file 
has changed before returning the cached copy.

This is (someone correct me if I'm wrong) every other proxy server on the
planet does it, for the most part, with some changes here and there. (I
know Brian mentioned that the AOL proxy keeps images for six hours without
checking, for example). IMO, and I've said this before, this should be the
default behavior of our server. It can be turned off if you want (with
CERN httpd and with my ill-fated Apache proxy module, you could), but
users will become quite irate if they keep getting old copies of documents
without any inclination of why. 

At least, that's my take on it.

--// Alexei Kosut // <> // Lefler on IRC --//
-----------------// <> -------// 
"To get the full effect of Pat Buchanan's speeches, they should be
read in the original German." //--------------------------------------

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