Suggestion: PUT if-not-modified-since

• From: Larry Masinter <masinter@parc.xerox.com>
• Date: Sat, 2 Sep 1995 22:34:05 PDT
• To: http-wg%cuckoo.hpl.hp.com@hplb.hpl.hp.com
• Message-Id: <95Sep2.223415pdt.2763@golden.parc.xerox.com>

While there is no 'LOCK' operation and I'm reluctant to try to define
one, I would suggest a if-not-modified-since header on 'PUT'.

This would at least allow you to build a web editor with verifier
semantics; that is, you would GET the document you want to edit, allow
the user to edit it, and then do a PUT if-not-modified-since. If
the document is unchanged from what was originally gotten, the PUT
would succeed (modulo access control, etc.); however, if the document
had changed since, the PUT would fail. The user agent would have to
deal with the situation in some way (e.g., retrieve the document anew,
compare it against the one that was originally obtained, allow the
user to merge edits, etc.), but at least you wouldn't have one edit
stepping on another.

Of course, this is for 1.1 or 1.2 or some such. Opinions?

Received on Saturday, 2 September 1995 22:36:42 UTC