- From: Shel Kaphan <sjk@amazon.com>
- Date: Mon, 13 Nov 1995 20:03:56 -0800
- To: Jeffrey Mogul <mogul@pa.dec.com>
- Cc: http-wg%cuckoo.hpl.hp.com@hplb.hpl.hp.com
Jeffrey Mogul writes: > (optional) (3) we extend the set of headers to include the > generalization "validator" which might be used to contain (e.g.) a > date, filesize, hash, checksum, or random number chosen by the server > as pertaining to a unique version of the document, and allow > "validator=<xxxxx>" to appear as a header in server responses as well > as in this header. > > As much as it pains me to disagree with someone who is trying to > agree with me ... > > The most important feature of a cache-validator is that it is > 100.00000000% opaque to clients and caches. Checksums aren't > opaque; dates aren't opaque; hashes aren't opaque. > > If the client or cache is able to do anything with the validator > besides send it back to the server, then it won't work. Which > is to say that some creative but misguided programmer will try > to use it in a way that will, sooner or later, make us all unhappy. > > -Jeff Much as I hate to agree with someone who is trying to disagree with me, I hate to disappoint you, but I think we're still agreeing. My suggestions were intended as things the server could use in computing the validator, not things the client would *know* were in the validator. I certainly DID NOT mean to imply that strings such as "Validator:date=01-March-1995" or "Validator:checksum=19283719827" would appear. I meant we'd see "Validator:8923984792" and that the server would be responsible for generating and understanding this. Sorry for being, uh, opaque about this. --Shel
Received on Monday, 13 November 1995 20:15:24 UTC