Some more comments about the WS-RA WS-Eventing draft

[Antoine Mensch <antoine.mensch@odonata.fr>]

Hi,

We've had quite a few discussions about event filtering (Issues 052 and 
056) while developing DPWS 1.1. Parts of the issues seemed to be related 
to the lack of filtering capabilities of the DPWS-specific action 
filter. I remember that one of the examples was about filtering of 
events on a per-print job basis (so that users receive only 
notifications about their own jobs). Now I don't know the DPWS Printer 
spec and the solution that is used to solve this problem, but it 
occurred to me that a possible solution could be for the Print service 
to create a new PrintJob EPR for each print job, and that the user could 
subscribe to the PrintJob EPR instead of to the Print service. Proper 
implementation on the server side would guarantee that only 
notifications related to a given print job would be sent to the subscriber.
My point here is not to reinvent the DPWS Printer wheel, nor to reopen 
closed issues, but to mention that by reading the WS-Eventing spec, the 
overall impression I got is that event sources are pretty static (as 
most Web services are), and that the possibility to dynamically create 
new event sources to represent some sort of dynamic topics does not 
stand out. I think it could be a valuable addition to the draft to make 
this possibility more explicit, maybe using a small example.

Cheers

Antoine