- From: Larry Masinter <masinter@parc.xerox.com>
- Date: Tue, 4 Jun 1996 16:21:33 PDT
- To: john@math.nwu.edu
- Cc: mogul@pa.dec.com, fielding@liege.ICS.UCI.EDU, http-wg%cuckoo.hpl.hp.com@hplb.hpl.hp.com
The last-modified date of a response should be the latest time at which the given response became a valid response for the given request (or any variations of the request as specified by the VARY header.) For web servers that are based on file systems, the "last-modified" time corresponds to the last time the file was modified, both for the case where there is a single file and when there are a fixed number of files and the appropriate file is chosen according to request headers. However, if you add a new file to the set, the 'last-modified' date of other members of the set would also change, so the CERN and Apache heuristic of using the maximum over all of the variants is a good conservative heuristic. For those web servers that do dynamic document construction or server-side includes based on content negotiation, other kinds of internal behavior might be more appropriate; this is why the protocol should not require any particular implementation. Larry
Received on Tuesday, 4 June 1996 16:23:43 UTC