p6: Vary and effects on future requests

Mark Nottingham <mnot@mnot.net> Mon, 29 April 2013 05:15 UTC

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Subject: p6: Vary and effects on future requests
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p6 4.3 says:

"""A Vary header field value of "*" always fails to match, and subsequent requests to that resource can only be properly interpreted by the origin server."""

Someone reading this could take away that *any* stored response with a Vary: * has an effect on ALL other stored responses that share that primary key (and a couple of the issues we discussed reflected this confusion, from memory).

As I recall, the goal for 4.3 Using Negotiated Responses was to assure that stored responses were independent and self-describing; i.e., that a cache didn't have to rationalise the value of the Vary header among multiple stored responses.

So, I'd suggest changing this to just:

"A Vary header field value of "*" always fails to match."

Make sense?

Mark Nottingham   http://www.mnot.net/