[ogsa-wg] FW: Issue #1 proposed resolution

[Tom Maguire]

Agreed.  +1 to not moving away from WS-A

Tom

Steve Tuecke wrote:

> The difference the WS-A working group seems to be expousing between 
> Reference Properties and Reference Parameters is that Reference 
> Properties comprise part of the identity of the resource (along with 
> the address), where as Reference Parameters do not constitute any part 
> of the identity.  In other words, Reference Parameters are like 
> cookies on the Web that are used to identify transient sessions, for 
> example.
>
> Given this viewpoint and the remove of Reference Properties, the 
> "correct" place to push this information is into the Address, rather 
> than the Reference Parameters.  But I agree that Reference Parameters 
> could technically be used for what we are currently using Reference 
> Properties.  In either case, the information still shows up in the 
> SOAP header of the request message -- either in the wsa:To header, or 
> in the Reference Parameters element.
>
> Note that this who discussion does not suggest to me that we should 
> move away from WS-A.  The reason I've always liked the move to WS-A 
> was that it clearly defined how information from the EPR was required 
> to show up in the SOAP header of a message -- the EPR address must be 
> put in the wsa:To header, and the Reference Properties must be copied 
> into the header.  This allows dispatch to be performed solely on the 
> contents of the SOAP message.  Previously the address to which a 
> message was being directed would only show up in the http post header 
> of the message, which made message dispatch somewhat more complex.  So 
> the practical ramification of this WS-A change on GT, for example, is 
> simply that we get the service address and resource identifier from 
> the wsa:To SOAP header, rather than from some other SOAP header that 
> came from the Reference Properties.
>
> -Steve
>
> On Jan 22, 2005, at 6:47 AM, Tom Maguire wrote:
>
>> I have to agree with Savas w.r.t. Reference Parameters.  The issue at 
>> hand in the WS-A working
>> group was the 'identity' semantic of Reference Properties vs URIs.  I 
>> do not think that reference
>> parameters will be removed from the spec and reference parameters can 
>> be used for service-side
>> dispatch.
>>
>> Tom
>>
>> Savas Parastatidis wrote:
>>
>>> Dear all,
>>>
>>> I agree with some of what Steve said bellow :-))
>>>
>>> The change does make a difference in implementations because if the
>>> information that was meant to be included in the Reference 
>>> Properties is
>>> now encoded in the Address property of an EPR (the URI) it cannot be
>>> echoed back as SOAP headers. This was part of the semantics of 
>>> Reference
>>> Properties.
>>>
>>> For a resource-oriented specification like WSRF, however, using URIs to
>>> identify resources is a good solution. On this I agree with Steve. The
>>> semantics of WSRF do not have to change even if it wasn't abstracted
>>> away from WS-Addressing. What is lost is the ability to echo back as
>>> SOAP headers any resource-specific information that may be required 
>>> by a
>>> SOAP intermediary to identify the targeted resource. If having SOAP
>>> headers is a requirement, though, I don't see why Reference Parameters
>>> couldn't be used.
>>> So, while Reference Properties have been removed, Reference Parameters
>>> are still there and while I would personally like to see them go too, I
>>> don't think it'll happen. The semantics of Reference Parameters are
>>> slightly different but I don't see why WSRF couldn't use them, if it
>>> needed to, instead of Reference Properties to carry resource-specific
>>> information.
>>>
>>> Best regards,
>>> -- 
>>> Savas Parastatidis
>>> http://savas.parastatidis.name
>>>
>>>
>>>> -----Original Message-----
>>>> From: owner-ogsa-wg at ggf.org [mailto:owner-ogsa-wg at ggf.org] On Behalf
>>>>
>>> Of
>>>
>>>> Steve Tuecke
>>>> Sent: Friday, January 21, 2005 9:55 PM
>>>> To: Ian Foster
>>>> Cc: 'Stephen Pickles'; 'OGSA-WG'; Steve Tuecke; Djaoui, A (Abdeslem)
>>>> Subject: Re: [ogsa-wg] FW: Issue #1 proposed resolution
>>>>
>>>> As far as I can tell, this decision has basically no effect on WSRF.
>>>> The argument being made by some in the WS-A working group is that it
>>>>
>>> is
>>>
>>>> equivalent and more true to the Web to carry a resource identifier as
>>>> part of the EPR address, rather than in a separate ResourceProperties
>>>> field -- that is, the resource reference should all be in the URI,
>>>> rather than split between a URI and separate resource properties.
>>>> Implementation-wise it certainly makes very little difference.  And
>>>>
>>> the
>>>
>>>> WSRF working group had already abstracted the WS-Resource reference
>>>>
>>> and
>>>
>>>> access pattern, so that it is not tightly coupled to WS-A and
>>>>
>>> reference
>>>
>>>> properties anyway, so WSRF specification-wise it makes no difference.
>>>>
>>>> -Steve
>>>>
>>>> On Jan 21, 2005, at 1:59 PM, Ian Foster wrote:
>>>>
>>>>
>>>>> I think the technical term is "carefully architected set of
>>>>> specifications" not "house of cards" (-:
>>>>>
>>>>> Regards -- Ian.
>>>>>
>>>>>
>>>>> At 05:10 PM 1/21/2005 +0000, Djaoui, A (Abdeslem) wrote:
>>>>>
>>>>> Well, it probably doesn't, because WSRF is now decoupled from
>>>>> WS-Addressing
>>>>> through the definition of the "abstract" resource Access Pattern,
>>>>> which
>>>>> defines different embodiments for different ways of accessing
>>>>>
>>> state.
>>>
>>>>>
>>>
>>>
>>>
>>
>>
>
>