Subject: Date header in cached responses

From: Adrien de Croy <[email-masked]>
Date: Mon, 15 Dec 2008 16:30:35 +1300

Hi all

please excuse me if this is in an FAQ somewhere.  I've been poring 
through the sections on caching in RFC2616, and having trouble 
understanding how a cache should generate a Date header when replying 
with a cached version of a resource.

It doesn't appear to be explicitly stated anywhere I've looked, but s 
13.2.5 (Disambiguating Expiration Values) makes me wonder if the cache 
should be sending back the original Date header it received when it 
added the entry to the cache.

If so, then should we consider the Age header to be "age in seconds 
since Date" or what?

If the cache has to store and send the original Date header, it then 
also needs to store an offset between its clock and the Orig-Server 
clock (based on the algorithm for corrected time) in order to calcualte 
an updated Age value. 

I would prefer if the cache could just send it's own local timestamp in 
Date, but that could cause issues with 13.2.5

Regards

Adrien

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