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RE: Another way of thinking about EPRs

From: Srinivas, Davanum M <Davanum.Srinivas@ca.com>
Date: Thu, 9 Dec 2004 22:13:24 -0500
Message-ID: <87527035FDD42A428221FA578D4A9A5B08907A8E@usilms24.ca.com>
To: "Martin Gudgin" <mgudgin@microsoft.com>, <public-ws-addressing@w3.org>

Martin, All,

Yes, I get it...Here's a variation of the argument I have been making
for i008 (not sure about i001). Section 2.4 of submission[1] talks about
comparing 2 EPR's. If I have to write a completely transparent BPEL or
WS-Choreography monitoring solution, I need to be able to look at the
wire and be able to figure out who is talking to who and keep track of
interactions between entities in the system. *IF* from the soap message
on the wire I can figure out the "who" portion..then I am all set.
According to 2.4, I can use the combination of [address] and [reference
properties] to figure out A is sending the message to B. BUT if I don't
have access to the EPR's themselves or list of all the Qname's that are
definitely reference properties, I cannot find out the "who". IF there
is some "annotation" (word used by Jonathan on IRC) on the soap message
on the wire then I can do this VERY easily.

So the basic question is - Is there consensus on whether we need some
"annotation"? (could be wrappers, could be attributes, could be
something else entirely). 

[1] http://www.w3.org/Submission/2004/SUBM-ws-addressing-20040810/

Thanks,
dims

-----Original Message-----
From: public-ws-addressing-request@w3.org
[mailto:public-ws-addressing-request@w3.org] On Behalf Of Martin Gudgin
Sent: Thursday, December 09, 2004 6:47 PM
To: public-ws-addressing@w3.org
Subject: Another way of thinking about EPRs


I've noticed that whenever we talk about issues i001 and i008, that
there is an implicit assumption that we start with an EPR and go from
that to the message. I think that in many cases, the reverse is actually
true, that is, people start with SOAP messages with headers in and then
decide how to communicate to a potential sender what those messages
should look like ( WRT the headers ).

For example, I want to have people send me messages that look like the
three below. 

<soap:Envelope>
 <soap:Header>
   <wsa:To>http://example.org/weather</wsa:To>
   <m:ServiceLevel>Gold</m:ServiceLevel>
   <m:TxId>1234</m:TxId>
 </soap:Header>
 <soap:Body>
 . . .
 </soap:Body>
</soap:Envelope>

<soap:Envelope>
 <soap:Header>
   <wsa:To>http://example.org/weather</wsa:To>
   <m:ServiceLevel>Silver</m:ServiceLevel>
   <m:TxId>1234</m:TxId>
 </soap:Header>
 <soap:Body>
 . . .
 </soap:Body>
</soap:Envelope>

<soap:Envelope>
 <soap:Header>
   <wsa:To>http://example.org/weather</wsa:To>
   <m:ServiceLevel>Gold</m:ServiceLevel>
   <m:TxId>4567</m:TxId>
 </soap:Header>
 <soap:Body>
 . . .
 </soap:Body>
</soap:Envelope>

How can I communicate to my users that I want the messages to look like
this? Ah, I know, I'll send them an EPR. Here are the three EPRs for the
messages above ( my seperation between Props/Params is arbitrary ).

<wsa:EndpointReference>
 <wsa:Address>http://example.org/weather</wsa:Address>
 <wsa:ReferenceProperties>
  <m:ServiceLevel>Gold</m:ServiceLevel>
 </wsa:ReferenceProperties>
 <wsa:ReferenceParameters>
  <m:ServiceLevel>1234</m:ServiceLevel>
 </wsa:ReferenceParameters>
</wsa:EndpointReference>

<wsa:EndpointReference>
 <wsa:Address>http://example.org/weather</wsa:Address>
 <wsa:ReferenceProperties>
  <m:ServiceLevel>Silver</m:ServiceLevel>
 </wsa:ReferenceProperties>
 <wsa:ReferenceParameters>
  <m:ServiceLevel>1234</m:ServiceLevel>
 </wsa:ReferenceParameters>
</wsa:EndpointReference>

<wsa:EndpointReference>
 <wsa:Address>http://example.org/weather</wsa:Address>
 <wsa:ReferenceProperties>
  <m:ServiceLevel>Gold</m:ServiceLevel>
 </wsa:ReferenceProperties>
 <wsa:ReferenceParameters>
  <m:ServiceLevel>4567</m:ServiceLevel>
 </wsa:ReferenceParameters>
</wsa:EndpointReference>

Does this make any sense?

Gudge
Received on Friday, 10 December 2004 03:13:26 GMT

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