If header field and conditional precedence

• From: Ken Murchison <murch@andrew.cmu.edu>
• Date: 2012年12月23日 16:00:46 -0500
• To: w3c-dist-auth@w3.org
• Message-ID: <50D770FE.9040808@andrew.cmu.edu>

Happy Holidays to All!
I'm trying to figure out where the If header field fits in the 
precedence order outlined in:
http://tools.ietf.org/html/draft-ietf-httpbis-p4-conditional-21#section-5
I assume that the If header field should be evaluated in a step 0, but 
my question is what should happen when the If header is present and 
evaluates to true? Should processing continue to step 3 or step 1? In 
other words, does If completely supersede If-Match, where a client 
wishing to submit both a state token and an ETag MUST only use If, or is 
a client allowed to submit a state token with If AND submit an ETag with 
If-Match?
In text, the two options might look something like this:
 0. When If is present, evaluate it:
 * if true, continue to step 3
 * if false, respond 412 (Precondition Failed)
 1. When If is not present and If-Match is present,
 evaluate it:
 ...
OR
 0. When If is present, evaluate it:
 * if true, continue to step 1
 * if false, respond 412 (Precondition Failed)
 1. When If-Match is present, evaluate it:
 ...
-- 
Kenneth Murchison
Principal Systems Software Engineer
Carnegie Mellon University

Received on Sunday, 23 December 2012 21:00:58 UTC