{"question":"What does a Vary header field on a response tell a cache?","state":"grounded","http_status":200,"index_version":"0fc1763d6701","answer":"A Vary header field in a response tells a cache which parts of the request message, aside from the method and target URI, might have influenced the origin server's selection of the response content. [rfc9110#12.5.5] A Vary header field containing a list of field names tells cache recipients that they must not use the response for a later request unless the later request has the same values for the listed header fields as the original request or the origin server has validated reuse of the response. [rfc9110#12.5.5] A Vary header field expands the cache key required to match a new request to a stored cache entry. [rfc9110#12.5.5] A Vary header field with the wildcard member \"*\" tells a recipient that it will not be able to determine whether the response is appropriate for a later request without forwarding the request to the origin server. [rfc9110#12.5.5]","message":"","citations":["rfc9110#12.5.5"],"supported":[{"text":"A Vary header field in a response tells a cache which parts of the request message, aside from the method and target URI, might have influenced the origin server's selection of the response content.","citation":"rfc9110#12.5.5","coverage":0.9474},{"text":"A Vary header field containing a list of field names tells cache recipients that they must not use the response for a later request unless the later request has the same values for the listed header fields as the original request or the origin server has validated reuse of the response.","citation":"rfc9110#12.5.5","coverage":0.9545},{"text":"A Vary header field expands the cache key required to match a new request to a stored cache entry.","citation":"rfc9110#12.5.5","coverage":1.0},{"text":"A Vary header field with the wildcard member \"*\" tells a recipient that it will not be able to determine whether the response is appropriate for a later request without forwarding the request to the origin server.","citation":"rfc9110#12.5.5","coverage":0.9444}],"withdrawn":[],"consulted":[{"section_id":"rfc9111#4.1","citation":"RFC 9111 Section 4.1: Calculating Cache Keys with the Vary Header Field","rank":1,"score":0.7774},{"section_id":"rfc9110#12.5.5","citation":"RFC 9110 Section 12.5.5: Vary","rank":3,"score":0.7302},{"section_id":"rfc9111#3.2","citation":"RFC 9111 Section 3.2: Updating Stored Header Fields","rank":7,"score":0.6116},{"section_id":"rfc9111#2","citation":"RFC 9111 Section 2: Overview of Cache Operation","rank":8,"score":0.5908},{"section_id":"rfc9111#4","citation":"RFC 9111 Section 4: Constructing Responses from Caches","rank":10,"score":0.569}],"budget":{"deadline_ms":150.0,"elapsed_ms":2.497,"exceeded":false,"stages":{"retrieval":0.436,"drafting":0.004,"grounding":2.034}}}