The Conditional GET Axiom, If_Modified_Since case

Ari Luotonen and Kevin Altis
World-Wide Web Proxies
Proceedings of the 1st International WWW Conference, May 1994.

        
        http(i, mq, mp, reqData, repData)
        /\ represents(mp, i, cbody)
        /\ mp < mq2
        /\ http(i, mq2, mp2, reqData2, repData2)
        /\ method(reqData2) = GET
        /\ Last_Modified(repData) = If_Modified_Since(reqData2)
        /\ status(repData2) = NotModified
        => represents(mp2, i, cbody);

        % The Conditional GET Axiom, If_None_Match case
        http(i, mq, mp, reqData, repData)
        /\ represents(mp, i, cbody)
        /\ mp < mq2
        /\ http(i, mq2, mp2, reqData2, repData2)
        /\ method(reqData2) = GET
        /\ ETag(repData) \in If_None_Match(reqData2) % leave * unspecified for now
        /\ status(repData2) = NotModified
        /\ ETag(repData2) = ETag(repData)
        => represents(mp2, i, cbody); % implied metadata?