- From: Henrik Frystyk Nielsen <frystyk@w3.org>
- Date: Mon, 27 Jul 1998 12:59:36 -0400
- To: Jim Gettys <jg@pa.dec.com>
- Cc: http-wg@cuckoo.hpl.hp.com, dmk@research.bell-labs.com, paulle@microsoft.com
At 09:23 7/27/98 -0700, Jim Gettys wrote: > >a) I'm nervous about adding anything like this at this date. I'd be happier >with a separate RFC describing what should happen... This should have >been dealt with months ago. I guess that applies to many of the edits performed now - the reason is probably that nobody has implemented PUT with etag preconditions until now - if you want to play with it then you can try out my implementation using the Web Commander - a libwww sample application [1]. >b) 4) seems a gross hack to me, adding another HEAD class special case >to the protocol. I didn't say that it is beautiful but it provides the needed functionality without breaking existing applications. If people don't care then we can dream up a new scheme altogether and don't have to be concerned about it here. >c) I suggest (described in a separate ID) a new header that conveys the >ETAG. This solves the race condition. To get any additional metadata >that might have changed, you'd perform a HEAD right after the PUT. This solution doesn't quite work the same way and doesn't have as useful semantics (special cases etags and allows race conditions on other metainformation). >d) you should go see if the WEBDAV folks have worried about this case; >they are sloppy enough they may have missed it, but then again, they >may have found it and have another fix for it... I have forwarded the mail to the webdav mailing list. Actually the current wording of etags in 14.19 is adequate as (if?) the requested variant in a first time PUT can be said to be the "requested variant". Whether that is obvious is another question - and of course it doesn't work with other metainformation: The ETag response-header field provides the current value of the entity tag for the requested variant. Henrik [1] http://www.w3.org/WinCom/ -- Henrik Frystyk Nielsen, World Wide Web Consortium http://www.w3.org/People/Frystyk
Received on Tuesday, 28 July 1998 11:41:23 UTC