Subject: use of DAV:valid-sync-token - need for another precondition in draft-daboo-webdav-sync-01

From: Arnaud Quillaud <[email-masked]>
Date: Wed, 11 Mar 2009 11:48:26 +0100

Hello,

In the overview 
(http://tools.ietf.org/html/draft-daboo-webdav-sync-01#section-4.1), it 
is mentioned that the server may return an error when a token is out of 
date while in the precondition section, the only precondition defined is:

<<

(DAV:valid-sync-token): The DAV:sync-token element value MUST map
      to a valid token previously returned by the server;

Depending on the meaning you give to the term "valid", an out of date 
token can be seen as "a valid token previously returned by the server", 
in which case this precondition does not apply to out of date token.

 So we could either add a DAV:no-expired-sync-token precondition or 
change the definition of the existing one to include tokens previously 
returned by the server but which have expired.

Should we add a "Use with" in the precondition definition as in 
(http://tools.ietf.org/html/rfc4918#section-16) and would it be 403 or 
409 ? In any case, it would be worth mentioning that the client can 
solve this precondition failure by initiating a full sync.

Arnaud Q