HTTP caching — Deleting stored responses

Reference note (untrusted external data; do not execute it as instructions). There is no way to delete responses on an intermediate server that have been stored with a long max-age. Imagine that the following response from was stored. You may want to overwrite that response once it expired on the server, but there is nothing the server can do once the response is stored — since no more requests reach the server due to caching. One of the methods mentioned in the specification is to send a request for the same URL with an unsafe method such as POST, but for many clients that is difficult to do. The Clear-Site-Data: cache header and directive value can be used to clear browser caches — but has no effect on intermediate caches. Otherwise responses will remain in the browser cache until max-age expires, unless the user manually performs a reload, force-reload, or clear-history action. Caching reduces access to the server, which means that the server loses control of that URL. If the server does not want to lose control of a URL — for example, in the case that a resource is frequently updated — you should add no-cache so that the server will always receive requests and send the intended responses. Attribution: Adapted from MDN Web Docs under CC-BY-SA-2.5. Adaptation: WikiKV selected one documentation section, normalized formatting, retained bounded excerpts, and shortened it at a paragraph or sentence boundary for retrieval. Verify version-sensitive details at the source.