RE: An analysis of mustUnderstand and related issues

Hi.

>> One of the points that Noah brings up 
>> is if the extensibility mechanism
>> indeed is good enough and that is a valid concern.

Noahs writeup was excellent. I suppose there are problems, but I dont think
SOAP is completely broken here. There is a possible interpretation of SOAP I
brought up at the 
F2F. I am not convinced that this (following) interpretation of SOAP is
incorrect.
 
1. There is always a header to a default actor with mustunderstand = 1. This
HAS to
   be processed last by the endpoint. The ultimate example is the soap body
that is
   equivalent to a header to the default actor with mustunderstand = 1. 
2. This implies the body cannot be processed by the endpoint if any header
with
   mustunderstand=1 to a specific actor was ignored. The endpoint obviously
has 
   to fault. WHAT ELSE CAN IT POSSIBLY DO? 
3. Therefore, all mustunderstand=1 will be processed if no fault is
generated.
4. Therefore mustunderstand=1 in soap is still workable.  

The ordering issue however is another dimension, multiple faults in a single
response
is also another dimension, so is compensation actions if some actions were
done and 
others were not. These dimensions all sound logically like extensions to
SOAP
or layered on top of SOAP. 

-----Original Message-----
From: Noah_Mendelsohn@lotus.com [mailto:Noah_Mendelsohn@lotus.com]
Sent: Wednesday, May 16, 2001 2:45 PM
To: Henrik Frystyk Nielsen
Cc: Doug Davis; xml-dist-app@w3.org
Subject: RE: An analysis of mustUnderstand and related issues


Henrik writes:

>> One of the points that Noah brings up 
>> is if the extensibility mechanism
>> indeed is good enough and that is a valid concern.

On the call just now, Glen brought up what I think is the area requiring 
greatest attention:  if several headers for the same header all indicate 
mustUnderstand, can we say anything about the order processed?  In SOAP 
1.1, I think the answer is "no".  Henrik suggests (a) that lexical order 
be significant -- I think that's a change to SOAP 1.1, though possibly a 
good idea (b) that rollback be required if later processing fails--I'm not 
sure this is practical, but we should consider it.  Also:  I don't think 
anything suggests that different actor URI's are necessarily different 
processors---so multiple header blocks addressed to what appear to be 
different actors might, in fact, interleave.  Consider "next" as just one 
example.  I'm not sure a lexical order dependency handles these cases 
gracefully.

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Noah Mendelsohn                                    Voice: 1-617-693-4036
Lotus Development Corp.                            Fax: 1-617-693-8676
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Received on Wednesday, 16 May 2001 18:30:34 UTC