Re: issue 6432 - yet another proposal

Jeff is correct. Opacity is not a quality of an URI. It is a principle: 
you should not infer anything from the
structure (or the content) of the path component of the URI. Note the use 
of the word "should" - I'll come back to that
later.

For instance, just because an URI ends in .pdf does NOT mean that the 
client/agent that uses that URI in a GET
should expect to receive an application/pdf media type in the response 
entity body. 

So, repeat after me, opacity is not a quality, it is a principle. One URI 
is neither more, nor less "opaque" than another.
Period.

Now, what Asir may be alluding to is that the MC Anon URI is constructed 
from a URI template:

        http://docs.oasis-open.org/ws-rx/wsmc/200702/anonymous?id=
{unique-String}

Here's where the opacity principle can be ignored: when the URI authority 
provides explicit information as to how to 
interpret the structure of the URI, as the WS-Make Connection spec [1] 
does. One can do a character for character
match of the string

        http://docs.oasis-open.org/ws-rx/wsmc/200702/anonymous?id=

If it matches the first 58 characters of another URI, then that (other) 
URI is a MCanon URI.

I refer you to the TAG finding that specifies that such practice is just 
fine thank-you very much [2] (3nd bullet in conclusions section):

"* Assignment authorities may publish specifications detailing the 
structure and semantics of the URIs they assign. Other users of those URIs 
may use such specifications to infer information about resources 
identified by URI assigned by that authority."

[1] 
http://docs.oasis-open.org/ws-rx/wsmc/200702/wsmc-1.1-spec-os.html#_Toc162743905
[2] http://www.w3.org/2001/tag/doc/metaDataInURI-31-20061204.html

Cheers,

Christopher Ferris
IBM Distinguished Engineer, CTO Industry Standards
IBM Software Group, Standards Strategy
email: chrisfer@us.ibm.com
blog: http://www.ibm.com/developerworks/blogs/page/chrisferris
phone: +1 508 234 2986





From:
Jeff Mischkinsky <jeff.mischkinsky@oracle.com>
To:
Yves Lafon <ylafon@w3.org>
Cc:
Gilbert Pilz <gilbert.pilz@oracle.com>, Asir Vedamuthu 
<asirveda@microsoft.com>, Doug Davis/Raleigh/IBM@IBMUS, 
"public-ws-resource-access@w3.org" <public-ws-resource-access@w3.org>
Date:
04/08/2009 03:16 PM
Subject:
Re: issue 6432 - yet another proposal
Sent by:
public-ws-resource-access-request@w3.org



hi,
   My understanding of the use of "opaque" wrt to URI's is that you 
are not supposed to infer anything from the structure of the URI, not 
that specific uri's don't have specific "meanings"/semantics as 
defined in specs.
   Otherwise it is totally meaningless to define a uri and give it 
semantics.
So this argument and asir's response don't make sense to me. You can 
certainly tell that the 2 uri's in question are different and you can 
certainly know what the semantics of using them are. So i don't see a 
problem.
    -jeff
On Apr 08, 2009, at 2:34 AM, Yves Lafon wrote:

> On Tue, 7 Apr 2009, Gilbert Pilz wrote:
>
>> WS-Addressing 1.0 - Core defines two "special" URIs;
>> "http://www.w3.org/2005/08/addressing/anonymous" and
>> "http://www.w3.org/2005/08/addressing/none". Messages targeted to 
>> either
>> of these URIs are processed differently from messages targeted to
>> "normal" URIs such as "http://webserivce.bea.com/. . .".
>
> Well, they are different, but unless you know WS-Addressing, or 
> unless you resolve http://www.w3.org/2005/08/addressing/anonymous 
> and find out the relationship between this URI and the WS-Addressing 
> spec.
> If you resolve http://webservice.bea.com/... you will probably have 
> information about the endpoint, or you may know it in advance from 
> another document. So both URIs are opaque, unless you know their 
> semantic.
>
>
> -- 
> Baroula que barouleras, au tiéu toujou t'entourneras.
>
>        ~~Yves
>
>

--
Jeff Mischkinsky  jeff.mischkinsky@oracle.com
Director, Oracle Fusion Middleware               +1(650)506-1975
                 and Web Services Standards              500 Oracle 
Parkway, M/S 2OP9
Oracle                                                   Redwood Shores, 
CA 94065