Re: source quality, caching, and Vary:

At 01:44 PM 2/12/96 PST, Paul Leach wrote:
>I don't understand how Vary: works where there are different levels of 
>source quality. It would be nice if the source quality of a resource 
>were returned someplace when using Vary: instead of URI:.  Or did I 
>miss something obvious?

There is no source quality with Vary.  Or rather, if there was a source
quality, it's transmittal would be internal to the server and useless to the
receiver.  The idea of Vary: is that it is appropriate only when the server
is unwilling to give both the full details of the variants, and/or unwilling
to use the standard content negotiaion algorithm.  The source quality is
only useful if the standard q*ql*qc*qe*qs algorithm is used.  If a origin
server uses a home-grown algorithm (like if HTTP_USER_AGENT == "Spyglass
Mosaic" then foo else bar) the whole q*ql*qc*qe*qs thing goes out the
window, and hence, qs with it.
-----
Dan DuBois, Software Animal           http://www.spyglass.com/~ddubois/
    Download a totally free copy of the Spyglass Web Server today!
        http://www.spyglass.com/products/server_download.html

Received on Monday, 12 February 1996 23:22:14 UTC