RE: [wsrf] Singleton Resource Pattern

["Sedukhin, Igor S" <Igor.Sedukhin@ca.com>]

Steve,

 

To reiterate. The separation has nothing to do with the notion of the "state". Can we try to look at things from a different perspective for a second?

 

1) access to properties (irrespective of one's view on the state). Just like sending SOAP message says nothing about the state, sending SOAP message to get a property value does not need to say anything about state. This is just a convention that simplifies some programming tasks and both could be described in WSDL. Very useful in general.

 

2) How to use WS-Addressing to identify stateful resources. This is just A way, not the only way. It may apply to 1), but does not have to.

 

-- Igor Sedukhin .. (igor.sedukhin@ca.com)
-- (631) 342-4325 .. 1 CA Plaza, Islandia, NY 11788

 

---

From: Steve Graham [mailto:sggraham@us.ibm.com]
Sent: Monday, July 12, 2004 6:38 PM
To: Vambenepe, William N
Cc: Sedukhin, Igor S; Rich Thompson; wsrf@lists.oasis-open.org
Subject: RE: [wsrf] Singleton Resource Pattern

I don't see the purpose to define 
how to access state when it is not clear how to identify the stateful 
resource. 

++++++++
Steve 
Graham
(919)254-0615 (T/L 444)
STSM, On Demand Architecture
Member, IBM 
Academy of Technology
<Soli Deo 
Gloria/>
++++++++

"Vambenepe, William N" <vbp@hp.com> 07/12/2004 06:12 PM

To:        "Sedukhin, Igor S" <Igor.Sedukhin@ca.com>, Rich Thompson/Watson/IBM@IBMUS, <wsrf@lists.oasis-open.org>         cc:                 Subject:        RE: [wsrf] Singleton Resource Pattern

+1 to Igor. Defining a way to reference a resource accessible 
through a Web service is not bad. It is just different from defining a Web 
service interface for querying properties and the two are better handled 
independently. 
  
Regards, 
  
William 
-----Original 
Message-----
From: Sedukhin, Igor S [mailto:Igor.Sedukhin@ca.com] 
Sent: Monday, July 12, 2004 1:10 PM
To: Rich Thompson; 
wsrf@lists.oasis-open.org
Subject: RE: [wsrf] Singleton Resource 
Pattern

But why does such 
"reference to a resource" have anything to do with the ability to retreive a 
property value? 
  
I think there are two distinct "faetures" here: 
    1) 
common definition of a "reference to a resource" 
  
  2) "properties" 
capability 
  
Both could be combined, but also stand alone. Both have distinct 
semantics and distinct value for Web services implementations. 
  
Therefore in my use 
case I used 2) and not necessarily 1). 
The way the WS-RF is today: 1) and 2) are inseparable.

-- Igor Sedukhin .. (igor.sedukhin@ca.com)
-- (631) 342-4325 .. 1 CA Plaza, Islandia, NY 11788

---

From: Rich Thompson [mailto:richt2@us.ibm.com] 
Sent: Monday, July 12, 2004 4:00 PM
To: 
wsrf@lists.oasis-open.org
Subject: RE: [wsrf] Singleton Resource 
Pattern


I 
think the question is whether each such service MUST define its own way of 
indicating such a reference or can there be value in defining a standardized 
means that a service MAY exploit if it chooses to. The fact that certain 
situations may call for a different form of reference being preferred doesn't 
negate the value of a shared definition of how to provide such a 
reference. 

Rich 
Thompson
OASIS WSRP TC Chair

"Sedukhin, Igor S" <Igor.Sedukhin@ca.com>

07/12/2004 03:50 PM

To	Rich Thompson/Watson/IBM@IBMUS, <wsrf@lists.oasis-open.org>
cc
Subject	RE: [wsrf] Singleton Resource Pattern

Why is X.509 
certificate in a WS-Security header not a sufficient means for referring to a 
proper "user" database record? 
 
The property is shared, there is one service, 
and there are multiple "records". Why can't I use WS-ResorceProperties spec to 
access UserName property without having to deal with stateful/stateless 
situation? 
 
It seems that ANYTHING in a message (body or a header) could be such 
"stateID". There may be no reason to set in stone what that is. Leave it to the 
implementers.

-- Igor Sedukhin .. (igor.sedukhin@ca.com)
-- (631) 342-4325 .. 1 CA Plaza, Islandia, NY 11788

---

From: Rich Thompson [mailto:richt2@us.ibm.com] 
Sent: Monday, July 12, 2004 3:40 PM
To: 
wsrf@lists.oasis-open.org
Subject: RE: [wsrf] Singleton Resource 
Pattern


But 
with the stateless character of web services, that UserName property would be 
shared by all users of the web service. There may be some usefulness to that, 
but it becomes far more useful when the web service interface fronts access to a 
multiplicity of state, each storing such a property. 

To make this a 
concrete example, presume the UserName property is really a reference to a field 
in a database. One could provide a separate web service interface for each 
record within the database, but it would be a much lighter (and frequently more 
useful) definition if there was a single web service interface that had some 
well defined means for indicating what record of the database was the target of 
the current invocation. WSRP had this type of need and had to define a means 
that is idiosyncratic to our protocol for passing the stateful reference. 
Defining a standardized means by which infrastructure can take more of the load 
for handling such references is one of the outcomes I would like to see from the 
WSRF effort. 

Rich Thompson
OASIS WSRP TC Chair

"Sedukhin, Igor S" <Igor.Sedukhin@ca.com>

07/12/2004 03:15 PM

To	Rich Thompson/Watson/IBM@IBMUS, <wsrf@lists.oasis-open.org>
cc
Subject	RE: [wsrf] Singleton Resource Pattern

Like I said, 
GetProperty would mean for example:... 

Web Service implements a UserName property. 
Client sends a GetResourceProperty SOAP message with WS-Security headers 
containing X.509 certificate. Web Service returns the UserName after matching 
the certificate.

-- Igor Sedukhin .. (igor.sedukhin@ca.com)
-- (631) 342-4325 .. 1 CA Plaza, Islandia, NY 11788

---

From: Rich Thompson [mailto:richt2@us.ibm.com] 
Sent: Monday, July 12, 2004 3:03 PM
To: 
wsrf@lists.oasis-open.org
Subject: RE: [wsrf] Singleton Resource 
Pattern


What would 
get/setProperty mean against the standard stateless character of the base Web 
Services definition? Before these become useful, you need some manner of 
modeling state. It seems to me the primary thrust behind defining WSRF is having 
a standard definition of how to model such stateful web services and as someone 
who has needed to idiosyncratically model state within the WSRP protocol, I see 
a lot of value in that effort. 

Rich Thompson
OASIS WSRP TC Chair

"Sedukhin, Igor S" <Igor.Sedukhin@ca.com>

07/12/2004 02:55 PM

To	Steve Graham/Raleigh/IBM@IBMUS
cc	<wsrf@lists.oasis-open.org>
Subject	RE: [wsrf] Singleton Resource Pattern

Then what 
value does the implied pattern add to the use case I have included? 

Why does resource 
pattern have to depend on WS-Addressing, EPRs and customizations of 
those? 

Why 
can't GetProperty/SetProperety be defined independently?

-- Igor Sedukhin .. (igor.sedukhin@ca.com)
-- (631) 342-4325 .. 1 CA Plaza, Islandia, NY 11788

---

From: Steve Graham [mailto:sggraham@us.ibm.com] 
Sent: Monday, July 12, 2004 2:44 PM
To: Sedukhin, Igor 
S
Cc: wsrf@lists.oasis-open.org
Subject: RE: [wsrf] 
Singleton Resource Pattern


>It seems that whether it is an "implied resource" or an 
"implied singleton" has nothing to do with GetResourceProperty (GetProperty for 
that sake) operation. In >other words use of WS-Addressing does not add any 
semantic value to the fact that one could retrieve a property by sending a 
message to a service. 

Unfortunately, I disagree.  The implied resource pattern 
clarifies a certain pattern relating a web service and a stateful resource. It 
is important that this pattern is clarified to allow a single web service to act 
as the Web services message processor for a plurality of stateful resources. 
Therefore the pattern of the message is formed to disambiguate which of the 
potentially many stateful resources is associated with the message is very 
important. 

sgg 

++++++++
Steve Graham
(919)254-0615 (T/L 444)
STSM, On 
Demand Architecture
Member, IBM Academy of Technology
<Soli Deo 
Gloria/>
++++++++

"Sedukhin, Igor S" <Igor.Sedukhin@ca.com> 07/12/2004 11:56 AM

To:        Steve Graham/Raleigh/IBM@IBMUS, <wsrf@lists.oasis-open.org>     cc:             Subject:        RE: [wsrf] Singleton Resource Pattern

Steve, 

Your example was 
interesting. How about this one: 

Web Service implements a UserName property. Client 
sends a GetResourceProperty SOAP message with WS-Security headers containing 
X.509 certificate. Web Service returns the UserName after matching the 
certificate. 
-- Is this a singleton or an implied resource pattern? One could 
claim that there is a user resource, however this interaction does not use 
WS-Addressing and moreover it would not be possible to build WS-RF qualified 
EPRs for such interaction. 

The same use case could be modified to include 
UserDiskQuota property, and the same argument would apply. 

It seems that whether it is an 
"implied resource" or an "implied singleton" has nothing to do with 
GetResourceProperty (GetProperty for that sake) operation. In other words use of 
WS-Addressing does not add any semantic value to the fact that one could 
retrieve a property by sending a message to a service.

-- Igor Sedukhin .. (igor.sedukhin@ca.com)
-- (631) 342-4325 .. 1 CA Plaza, Islandia, NY 11788