[5662] in www-talk@info.cern.ch
Cache servers and Date: header
daemon@ATHENA.MIT.EDU (John Franks)
Fri Sep 16 18:58:08 1994
Date: Fri, 16 Sep 1994 22:28:56 +0200
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Errors-To: listmaster@www0.cern.ch
Reply-To: john@math.nwu.edu
From: john@math.nwu.edu (John Franks)
To: Multiple recipients of list <www-talk@www0.cern.ch>
According to Karl Auerbach:
> > > for cache management.
> > Can you explain this? If the Date: is just the current time doesn't the
> > client/proxy server know it as well as the server.
>
> The Date: line should indicate when the document was peeled from the
> original content provider. If a cache intervenes, it should not
> change the Date: line. Thus there may be a substantial difference
> between the Date: as published and the time of document reception.
>
Do caching servers add there own headers before passing along the document?
I hope so. As with mail it should be possible from the header to learn
through whose hands a document has passed on the way to the client. Also
each caching server should add a Date-cached: header similar to the mail
Received: header.
If this is done there really isn't much reason for having a Date:
header from the original server (the Last-Modified-Date: is analogous
to the Date: in mail). On the other hand it isn't very expensive
either.
John Franks Dept of Math. Northwestern University
john@math.nwu.edu
