RFC 7234, "Hypertext Transfer Protocol (HTTP/1.1): Caching", June 2014

Note: This RFC has been obsoleted by RFC 9111

Errata ID: 6279
Status: Held for Document Update
Type: Technical
Publication Format(s) : TEXT
Reported By: Todd Greer
Date Reported: 2020-09-04
Held for Document Update by: Francesca Palombini
Date Held: 2021-04-29

Section 4.2.4 says:

A cache MUST NOT generate a stale response if it is prohibited by an
explicit in-protocol directive (e.g., by a "no-store" or "no-cache"
cache directive, a "must-revalidate" cache-response-directive, or an
applicable "s-maxage" or "proxy-revalidate" cache-response-directive;
see Section 5.2.2).

It should say:

A cache MUST NOT generate a stale response if it is prohibited by an
explicit in-protocol directive (e.g., by a "no-cache"
cache directive, a "must-revalidate" cache-response-directive, or an
applicable "s-maxage" or "proxy-revalidate" cache-response-directive;
see Section 5.2.2).

Notes:

The examples of directives that prohibit stale responses includes "no-store", but the definitions of "no-store" in 5.2.1.5 and 5.2.2.3 don't prohibit serving stale responses, and there is no other mention in RFC 7234 (or elsewhere) of "no-store" prohibiting serving stale responses.

If a "no-store" request directive is intended to prohibit serving stale responses, 5.2.1.5 should say so. (The question is meaningless for "no-store" response directives, since those should never be found in a cache.)

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