[[ To mark a response as "never expires," an origin server sends an Expires date approximately one year from the time the response is sent. HTTP/1.1 servers SHOULD NOT send Expires dates more than one year in the future. ]]
The expires and max-age elements look fine. I hesitate at bringing in a caching discussion. I'm much more comfortable leaving the definition of caching rules to the protocol level (HTTP) rather than the format extension level. Namely, I don't want to have to go into defining rules for how HTTP headers that affect caching interact with the expires and max-age elements... IMHO, there is simply no value in that.rules as atom:author elements.
Here it is: <http://www.intertwingly.net/wiki/pie/PaceCaching>
The expires and max-age extension elements affect the feed / entry on the application level not the document level. HTTP caching works on the document level.
This is easy enough.Adding max-age also means defining IntegerConstruct and disallowing white space around it. Formerly, it was OK as a text construct, but the white space issues change that.
Also, we should decide whether cache information is part of the signature.-1. let's let caching be handled by the transport layer.
I can see arguments either way.