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Re: LC 76 - What makes a msg WS-A?

From: Anish Karmarkar <Anish.Karmarkar@oracle.com>
Date: Fri, 15 Jul 2005 13:06:06 -0700
Message-ID: <42D8172E.8060100@oracle.com>
To: "Rogers, Tony" <Tony.Rogers@ca.com>
CC: "Winkler, Steve" <steve.winkler@sap.com>, Martin Gudgin <mgudgin@microsoft.com>, David Orchard <dorchard@bea.com>, David Hull <dmh@tibco.com>, Katy Warr <katy_warr@uk.ibm.com>, public-ws-addressing@w3.org

Rogers, Tony wrote:
> I'm beginning to think that we regard a message as being sent down the 
> "this is a WS-A message" fork in the trail when it has an Action header, 
> or another WS-A header with mustUnderstand set to true. Otherwise it 
> goes down the "this is NOT a WS-A message" fork.
>  
> Agreed? Violently rejected?
> 

I don't quite agree with the above formulation (the 'otherwise' part).
The mU='1' simply states that the message must be processed as a WSA 
message. If mU='0', it *may* still be processed as a WSA message, if the 
receiver chooses to do so. In which case the receiver has to ensure that 
all the WSA rules are adhered to. If not, then throw a fault.

-Anish
--

> Tony
> 
>     -----Original Message-----
>     *From:* public-ws-addressing-request@w3.org on behalf of Winkler, Steve
>     *Sent:* Fri 15-Jul-05 18:59
>     *To:* Martin Gudgin; David Orchard; David Hull
>     *Cc:* Katy Warr; public-ws-addressing@w3.org
>     *Subject:* RE: LC 76 - What makes a msg WS-A?
> 
>      
>     Hi Katy,
>      
>     Look what you started... ;-)
>      
>     In sifting through the mails, I've gathered that:
>      
>     If the client expects that WS-A machinery is to be engaged on the
>     endpoint to which they are sending, they need to include at least
>     one wsa:Header with a mustUnderstand attribute set to true.  The
>     receiving side needs to check if any of the wsa:Header elements
>     defined in the specification are present with the mU attribute set
>     to true, if so they need to process the message in accordance with
>     the WS-A spec (this includes faulting if wsa:Action is not present,
>     one reason why I wasn't happy with Gudge's original answer). 
>      
>     Now for some questions:
>      
>     Does this reflect an accurate understanding of the discussion up to
>     this point? 
>     If so, Katy, does this satisfy your original question? 
>     Is the group satisfied with this summary? 
>     Should we state something like this explicitly in the spec?
>      
>      
>     Cheers,
>     Steve
>      
>      
>     -------------------------
>     Steve Winkler
>     SAP AG
>      
> 
>      
> 
>         ------------------------------------------------------------------------
>         *From:* public-ws-addressing-request@w3.org
>         [mailto:public-ws-addressing-request@w3.org] *On Behalf Of
>         *Martin Gudgin
>         *Sent:* Thursday, Jul 14, 2005 3:08 PM
>         *To:* David Orchard; David Hull
>         *Cc:* Katy Warr; public-ws-addressing@w3.org
>         *Subject:* RE: LC 76 - What makes a msg WS-A?
> 
>         I thought it was clear too. And it fits with the SOAP processing
>         model and so works for endpoints which were deployed long before
>         WS-A was a twinkle in the eye of it's multiple parents...
>          
>         Gudge
> 
>             ------------------------------------------------------------------------
>             *From:* David Orchard [mailto:dorchard@bea.com]
>             *Sent:* 14 July 2005 22:32
>             *To:* David Hull; Martin Gudgin
>             *Cc:* Katy Warr; public-ws-addressing@w3.org
>             *Subject:* RE: LC 76 - What makes a msg WS-A?
> 
>             I thought it was clear.  As soon as a single ws-a header is
>             marked with mU, then a fault will be thrown if there are any
>             missing headers like Action.  If there are no headers marked
>             with mU and there are missing headers, then it's up to the
>             receiver to decide whether to throw a fault or ignore all
>             the ws-a headers.
> 
>              
> 
>             Dave
> 
>              
> 
>              
> 
>             ------------------------------------------------------------------------
> 
>             *From:* David Hull [mailto:dmh@tibco.com]
>             *Sent:* Thursday, July 14, 2005 2:25 PM
>             *To:* Martin Gudgin
>             *Cc:* David Orchard; Katy Warr; public-ws-addressing@w3.org
>             *Subject:* Re: LC 76 - What makes a msg WS-A?
> 
>              
> 
>             Martin Gudgin wrote:
> 
>             +1
> 
>             Am I correct in reading that as "we should throw a fault if
>             there is a wsa:ReplyTo but no wsa:Action" and we're back on
>             the same page?  I hope so, but when you say things like "I
>             don't see why we want to mandate a fault in such a case." it
>             seems like you're saying that we shouldn't (or at least
>             shouldn't feel obliged to) throw a fault in such cases.
> 
>             Perhaps you could enumerate with which combinations of
>             headers a WSA-compliant endpoint should and should not
>             produce a fault?  We can then check that against the rules
>             in section 3 and know whether we need to have any further
>             discussion.
> 
>              
> 
>             Gudge
> 
>                  
> 
>                 ------------------------------------------------------------------------
> 
>                 *From:* David Orchard [mailto:dorchard@bea.com]
>                 *Sent:* 14 July 2005 22:03
>                 *To:* David Hull; Martin Gudgin
>                 *Cc:* Katy Warr; public-ws-addressing@w3.org
>                 <mailto:public-ws-addressing@w3.org>
>                 *Subject:* RE: LC 76 - What makes a msg WS-A?
> 
>                 It seems to me that you can't pick and choose which
>                 headers to support.  If there are any insufficient ws-a
>                 information (like contains a replyTo but no Action) then
>                 none of the ws-a processing can be invoked.  It's not a
>                 smorgasborg.
> 
>                  
> 
>                 Dave
> 
>                  
> 
>                 ------------------------------------------------------------------------
> 
>                 *From:* public-ws-addressing-request@w3.org
>                 <mailto:public-ws-addressing-request@w3.org>
>                 [mailto:public-ws-addressing-request@w3.org] *On Behalf
>                 Of *David Hull
>                 *Sent:* Thursday, July 14, 2005 1:41 PM
>                 *To:* Martin Gudgin
>                 *Cc:* Katy Warr; public-ws-addressing@w3.org
>                 <mailto:public-ws-addressing@w3.org>
>                 *Subject:* Re: LC 76 - What makes a msg WS-A?
> 
>                  
> 
>                 Martin Gudgin wrote:
> 
>                 I agree with your analysis of the three steps. I don't
>                 see why we want to mandate a fault in such a case. The
>                 client gets to decide whether he wants a fault or not
>                 based on whether he marks the header mU='true' or not...
> 
>                 What would happen to the [reply endpoint] in this case
>                 (or rather, these cases, as mU may be true or not)? 
>                 Would it be used as a reply address?  Would it be
>                 silently ignored? Something else?
> 
>                 In the first case, it seems strange to follow WSA rules
>                 but not complain about a missing mandatory header.  In
>                 the second case, it seems less than robust to silently
>                 ignore a field that would otherwise have a significant
>                 effect on processing.
> 
>                 Not sure about the third case.
> 
> 
>                  
> 
>                 Gudge
> 
>                      
> 
>                     ------------------------------------------------------------------------
> 
>                     *From:* David Hull [mailto:dmh@tibco.com]
>                     *Sent:* 14 July 2005 21:21
>                     *To:* Martin Gudgin
>                     *Cc:* Katy Warr; public-ws-addressing@w3.org
>                     <mailto:public-ws-addressing@w3.org>
>                     *Subject:* Re: LC 76 - What makes a msg WS-A?
> 
>                     Martin Gudgin wrote:
> 
>                     Well, one could argue that the endpoint that accepts
>                     WS-A messages and the one that accepts non-WS-A
>                     message are not actually the same endpoint despite
>                     the fact that they're listening on the same URI, I
>                     suppose...
> 
>                     Sure, but the multiplexing still has to be done one
>                     way or another.
> 
> 
>                      
> 
>                     I'm still not seeing why the endpoint can't use the
>                     following sequence of steps;
> 
>                      
> 
>                     1.    Does the message contain a wsa:Action header?
> 
>                     2.    If the answer to question 1. is 'Yes' then
>                     look for other wsa: * headers and populate abstract
>                     properties as appropriate.
> 
>                     3.    If the answer to question 1 is 'No' then
>                     process the message using normal SOAP rules
>                     (including raising mU faults if there are any other
>                     wsa:* headers marked mU='true' )
> 
>                     That will not produce a fault if a message contains
>                     an explicit wsa:ReplyTo (with no mU) but no
>                     wsa:Action, right?  The test in step 1 fails and we
>                     go straight to step 3.  So it's OK iff we don't want
>                     a fault in such a case.  My understanding is we /do/
>                     want a fault in such a case.
> 
> 
>                      
> 
>                     Gudge
> 
>                          
> 
>                         ------------------------------------------------------------------------
> 
>                         *From:* David Hull [mailto:dmh@tibco.com]
>                         *Sent:* 14 July 2005 20:58
>                         *To:* Martin Gudgin
>                         *Cc:* Katy Warr; public-ws-addressing@w3.org
>                         <mailto:public-ws-addressing@w3.org>
>                         *Subject:* Re: LC 76 - What makes a msg WS-A?
> 
>                         Martin Gudgin wrote:
> 
>                         Why is it a problem if a message which doesn't
>                         have wsa:Action in it is NOT subject to
>                         'validation' (what does that mean, BTW) by the
>                         receiver?
> 
>                         Yeah, I'm not comfortable with the terminology
>                         either.
> 
>                         The question is, should a WSA compliant
>                         /endpoint/ throw a fault if it gets a message
>                         with (say) a [reply endpoint] and no [action]?
> 
>                         If I understand right, you're saying that
>                         (straightforwardly), it should.  That's
>                         certainly how I'd interpret the current core.
> 
>                         Section 3 (specifically section 3.1) says that
>                         [action] is required (i.e., its cardinality is
>                         (1..1)), so the only question (and the one I
>                         think Katy was asking) is, when does section 3
>                         apply?
> 
>                         There appears to be consensus that endpoints
>                         should be able to accept both old-style and
>                         new-style requests without problem.  This means
>                         that such an endpoint must be prepared to accept
>                         messages with no wsa: headers at all -- contrary
>                         to as strict reading of section 3.  In
>                         particular, such an endpoint should /not/ fault
>                         if wsa:Action is absent unless other wsa:
>                         headers are present.  In such a case, section 3
>                         does not apply universally, and we want to be
>                         able to say when it does and doesn't apply.
> 
>                         So what's the best way to say this?  We can't
>                         use abstract properties, since they may be
>                         defined even if there are no wsa: headers in the
>                         incoming message.  So we have to look at the
>                         incoming infoset.  In short, an endpoint capable
>                         of handling both styles should apply the
>                         constraints in section 3 if the incoming SOAP
>                         message contains any wsa: headers, and should
>                         follow the pre-WSA behavior otherwise.  This is
>                         fine as long as the underlying transport binding
>                         doesn't synthesize wsa: headers that aren't
>                         explicitly there.  Otherwise, we'd need some
>                         other way of figuring out if the sender meant to
>                         use WSA.
> 
>                         Does that make more sense?  I believe this is a
>                         long-standing and thoroughly discussed issue. 
>                         If you were thinking of something else, let's
>                         sort that out first.
> 
> 
> 
>                         Gudge
> 
>                              
> 
>                             ------------------------------------------------------------------------
> 
>                             *From:* David Hull [mailto:dmh@tibco.com]
>                             *Sent:* 14 July 2005 20:29
>                             *To:* Martin Gudgin
>                             *Cc:* Katy Warr; public-ws-addressing@w3.org
>                             <mailto:public-ws-addressing@w3.org>
>                             *Subject:* Re: LC 76 - What makes a msg WS-A?
> 
>                             Martin Gudgin wrote:
> 
>                             OK, I'm confused.
> 
>                              
> 
>                             Why do you conclude that the answer to my
>                             question "Given that the wsa:Action header
>                             is mandatory, isn't it the presence of that
>                             header?" is 'No'.
> 
>                              
> 
>                             I would have come to the opposite conclusion;
> 
>                              
> 
>                             I have an endpoint that understands
>                             WS-Addressing. It receives a message that
>                             contains wsa:ReplyTo but no wsa:Action. It
>                             generates a fault. Seems pretty
>                             straightforward to me.
> 
>                             Sure.  That is a perfectly straightforward
>                             rule.  In fact, it's implied by what we say
>                             in section 3.3.
> 
>                             I thought you were trying to answer the
>                             question "When is an incoming message deemed
>                             to be a WS-Addressing message and therefore
>                             subject to the appropriate WS-Addressing
>                             validation?" with (rephrasing the reply as a
>                             statement) "It's subject to WSA validation
>                             if the wsa:Action header is present."  And
>                             of course, this clearly won't work, since it
>                             specifically doesn't try to validate a
>                             message with wsa:ReplyTo and no wsa:Action.
> 
>                             If you meant something else, then never
>                             mind.  It's probably not worth sorting.
> 
> 
>                              
> 
>                             I have an endpoint that doesn't understand
>                             WS-Addressing. It receives a message that
>                             contains one or more wsa: headers, it either
>                             ignores them or generates a mustUnderstand
>                             fault depending on whether those headers are
>                             marked mustUnderstand='true' or not. Again,
>                             seems pretty straightforward to me.
> 
>                             Sure.  As I said, we're talking about
>                             behavior of endpoints, not properties of
>                             messages.
> 
>                             As DaveO says, the interesting case is that
>                             of an endpoint that wants to accept non-WSA
>                             messages without complaint but also handle
>                             WSA messages properly.
> 
> 
>                              
> 
>                             Gudge
> 
>                                  
> 
>                                 ------------------------------------------------------------------------
> 
>                                 *From:* David Hull [mailto:dmh@tibco.com]
>                                 *Sent:* 14 July 2005 18:02
>                                 *To:* Martin Gudgin
>                                 *Cc:* Katy Warr;
>                                 public-ws-addressing@w3.org
>                                 <mailto:public-ws-addressing@w3.org>
>                                 *Subject:* Re: LC 76 - What makes a msg
>                                 WS-A?
> 
>                                 Martin Gudgin wrote:
> 
>                                  
> 
>                                      
> 
>                                     ------------------------------------------------------------------------
> 
>                                     *From:* David Hull
>                                     [mailto:dmh@tibco.com]
>                                     *Sent:* 14 July 2005 16:32
>                                     *To:* Martin Gudgin
>                                     *Cc:* Katy Warr;
>                                     public-ws-addressing@w3.org
>                                     <mailto:public-ws-addressing@w3.org>
>                                     *Subject:* Re: LC 76 - What makes a
>                                     msg WS-A?
> 
>                                     Is this really a question of how to
>                                     support both WSA and old-style HTTP
>                                     requests on the same endpoint?  
>                                     [MJG] I don't know, I didn't ask the
>                                     original question.
> 
>                                 Hmm ... my message was in-reply-to
>                                 yours, but the question was really aimed
>                                 more at Katy.  Maybe we need BPEL here :-).
> 
> 
> 
>                                       I.e., if I don't see any WSA
>                                     headers at all, I assume it's an
>                                     old-style request and act
>                                     accordingly, but if I see anything
>                                     WSA, I follow the rules in section 3? 
>                                     [MJG] I guess one could do that...
> 
>                                 Well, one should do /something/ to
>                                 ensure that old-style requests are
>                                 accepted as such.
> 
> 
> 
>                                     The tricky bit is that, since MAPs
>                                     like [destination] and [reply
>                                     endpoint] can default, a message
>                                     with no wsa: elements on the wire
>                                     could still be assigned values for
>                                     some of its MAPs, since the
>                                     /infoset/ will still have values for
>                                     the corresponding elements. 
> 
>                                     [MJG] Which Infoset are you talking
>                                     about? The XML Infoset has no such
>                                     values.
> 
>                                 Sorry, I didn't get that quite right.  I
>                                 was going by section 3.2, particularly
>                                 the descriptions of wsa:To:
> 
>                                 This OPTIONAL element (whose content is
>                                 of type xs:anyURI) provides the value
>                                 for the [destination] property. If this
>                                 element is NOT present then the value of
>                                 the [destination] property is
>                                 "http://www.w3.org/@@@@/@@/addressing/anonymous"
>                                 <http://www.w3.org/@@@@/@@/addressing/anonymous>.
> 
> 
>                                 (and similarly for wsa:ReplyTo). I
>                                 initially misread this as stating that
>                                 the element defaulted, as opposed to the
>                                 MAP.  So s/since the /infoset/ will
>                                 still have values for the corresponding
>                                 elements/since the properties are
>                                 defaulted in the absence of the
>                                 corresponding elements in the infoset/. 
>                                 This sort of confusion could be seen as
>                                 an argument against the two-layered
>                                 approach (or simply as an argument that
>                                 I read too quickly).
> 
>                                 In any case, you can't simply look at
>                                 the abstract properties and say "some
>                                 WSA properties are defined, so it's a
>                                 WSA message".
> 
> 
> 
>                                        So either we have to drop down to
>                                     look at the infoset level, and in
>                                     particular at the non-defaulted
>                                     elements in the infoset, or we have
>                                     to find some marker that can't be
>                                     defaulted away.  This is why the
>                                     [action] property looks significant
>                                     here.  But on the other hand, what
>                                     if I include a wsa:ReplyTo element
>                                     and no action?  By the "it's WSA iff
>                                     [action] is present" rule, that's
>                                     not a WSA message and therefore not
>                                     an error.  This seems wrong. 
>                                     [MJG] Why does it seem wrong?
> 
>                                 It seems wrong not to fault for a
>                                 message that contains a wsa:ReplyTo on
>                                 the wire but not a wsa:Action.
> 
> 
> 
>                                     Put another way, when would one get
>                                     a fault for omitting [action]? 
>                                     [MJG] Whenever another wsa:
>                                     header is present in a message.
> 
>                                 In other words, the answer to your
>                                 question ("Given that the wsa:Action is
>                                 mandatory, isn't it the presence of that
>                                 header?") is "No."
> 
>                                 This is why at the Berlin meeting we
>                                 tried to make sure that all the
>                                 possibilities were covered for various
>                                 combinations of the MAPs.  I believe
>                                 we've satisfied ourselves that they are,
>                                 but perhaps we need to revisit this work?
> 
> 
> 
> 
>                                     Martin Gudgin wrote:
> 
>>                                     Given that the wsa:Action is
>>                                     mandatory, isn't it the presence
>>                                     of that header?
>>
>>                                      
>>
>>                                     Gudge
>>
>>                                          
>>
>>                                         ------------------------------------------------------------------------
>>
>>                                         *From:*
>>                                         public-ws-addressing-request@w3.org
>>                                         <mailto:public-ws-addressing-request@w3.org>
>>                                         [mailto:public-ws-addressing-request@w3.org]
>>                                         *On Behalf Of *Katy Warr
>>                                         *Sent:* 14 July 2005 16:07
>>                                         *To:*
>>                                         public-ws-addressing@w3.org
>>                                         <mailto:public-ws-addressing@w3.org>
>>                                         *Subject:* LC 76 - What makes
>>                                         a msg WS-A?
>>
>>
>>                                         Please could we discuss the
>>                                         following in the context of LC76?
>>
>>                                         When is an incoming message
>>                                         deemed to be a WS-Addressing
>>                                         message and therefore subject
>>                                         to the appropriate
>>                                         WS-Addressing validation?   Is
>>                                         it based on the presence of
>>                                         any WS-addressing Message
>>                                         Addressing Property?  For
>>                                         example, does a message
>>                                         containing a reference
>>                                         parameter (but no other
>>                                         WS-Addressing information)
>>                                         need to result in a
>>                                         MessageAddressingHeaderRequired?
>>                                            Or, for example, does the
>>                                         declaration of the wsa
>>                                         namespace rendor the message
>>                                         WS-Addressing?
>>
>>                                         Thanks
>>                                         Katy
>>
>                                      
> 
>                                  
> 
>                              
> 
>                          
> 
>                      
> 
>                  
> 
>              
> 
Received on Friday, 15 July 2005 20:22:16 GMT

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