RE: Issue 130 - DPWS - Fault Handling Clarification Needed

[Dan Driscoll <Dan.Driscoll@microsoft.com>]

The normative addition makes sense—we don’t want services to send a SubscribeResponse if the subscription failed, or if the service intends to fault immediately afterward.

 

I prefer that the spec stay silent on the case where the service does not know about its own events ahead of time.  I expect many implementers wire the list of Actions into their Subscribe handler specifically to handle this case (and that’s a good thing), so anyone who doesn’t feel like plumbing this list into Subscribe could arguably be in a “dynamic environment” where they don’t know what events are available when they receive the Subscribe.

 

That said, I realize there are very valid technical reasons why the service may not know at Subscribe time, but I prefer that those implementers deal with that on a case-by-case basis.

 

The current pattern is very simple, and lets higher-layer specs be very straightforward about how they define optional events without having to worry about the case where the service may be in a “dynamic environment.”

 

Thanks Travis

--D

 

From: Ram Jeyaraman [mailto:Ram.Jeyaraman@microsoft.com]
Sent: Tuesday, December 16, 2008 8:17 AM
To: ws-dd@lists.oasis-open.org
Subject: [ws-dd] Issue 130 - DPWS - Fault Handling Clarification Needed

 

This issue is assigned the number 130. For further discussions on this issue, please refer to this issue number or use this thread.

 

From: Travis M Grigsby [mailto:travisg@us.ibm.com]
Sent: Tuesday, December 16, 2008 8:05 AM
To: Ram Jeyaraman
Cc: Scott de Deugd; Doug Davis; Mike Kaiser
Subject: WS-DD Issue: Fault Handling Clarification Needed

 

Hello Ram - I had an issue to add!  Please let me know if this needs further clarification.

Subscription Filter - Fault Handling Clarification Needed
Description:
Document: DPWS 1.1-spec-wd-02-1
Line number:  Line 889
Owner: Travis Grisby:

Section 6.1.1 says:
R3020: If none of the Notifications exposed by a HOSTED SERVICE match the [action] values in a Subscribe SOAP ENVELOPE Filter whose Dialect is "http://schemas.xmlsoap.org/ws/2006/02/devprof/Action", the HOSTED SERVICE MUST generate a wsdp:FilterActionNotSupported SOAP Fault.

When should this be raised? During a subscribe?
Does this imply that an event sink must know all of the types of notifications its going to send?.


Proposed Resolution (changes in red):


In some dynamic environments, it may not be possible for a HOSTED SERVICE to determine a complete list of possible events and actions prior to generating them.  In the event that the list is known, it is important to check this list against the filter provided in the Subscribe message in order to notify the subscriber immediately of an erroneously specified filter.
 
R3020:  If none of the Notifications exposed by a HOSTED SERVICE match the [action] values in a Subscribe SOAP ENVELOPE Filter whose Dialect is "http://schemas.xmlsoap.org/ws/2006/02/devprof/Action", the HOSTED SERVICE MUST return a wsdp:FilterActionNotSupported SOAP Fault instead of a SubscribeResponse.

Thanks!
Travis

Travis M. Grigsby
SWG Emerging Standards
(512) 591-2571