Re: If-ID and Unless-ID Preconditions

> Now we can argue about the syntax of the Content-ID.  You write
> 
>                Content-ID  =  "Content-ID" ":" cid
>                cid  =  <a content-id as defined in RFC 1521>
> 
> I believe this means 
> 
>                cid = local-part "@" domain

Actually, I should have put "msg-id" as in MIME, which is defined
by reference to RFC 822:

     msg-id      =  "<" addr-spec ">"

which is actually a bit more complicated than <local-part@domain>.

Suffice it to say that we should come up with a set of suggested
formats.  For instance, I like

     <8fdea782afd3973fg@md5.my.server>

but there are many other possibilities that give us the desired
characteristics of world-unique, must change if content changes,
and should not change if content remains the same (for that Request-URI).

The reason to stay with the MIME syntax is for maximum interoperability.
We should ask Ned if there are any plans/desires to change that syntax
before trying to come up with something more compact.


 ...Roy T. Fielding
    Department of Information & Computer Science    (fielding@ics.uci.edu)
    University of California, Irvine, CA 92717-3425    fax:+1(714)824-4056
    http://www.ics.uci.edu/~fielding/