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Subject: RE: [ebxml-msg] Groups - AS4-profile-v1.0-wd20.odt uploaded


I think we need a meeting with the full TC, including the AS4 editors, to resolve this.
 
I've shown how payload part references can be included, and a valid ebBP signal can be generated for any AS4 message, using an XSLT stylesheet.  It follows the pattern that e-business receipts provide a listing of line items that mirrors the line items in the related messages. E.g. a UBL Receipt Advice or GS1 eCom XML ReceivingAdvice mirror the structure of the corresponding DespatchAdvice business documents. But I'll admit it is somewhat contrived.
 
However, the alternative of having an ebBP signal receipt that has a single part identifier, the value of which is not a part identifier but a message identifier, which is redundant as it is already present as the value of the RefToMessageId,  and which does not have part references for the actual message parts,  is even worse. The ebBP structure may be valid and it's simple but it's an ugly kludge.
 
Changing the ebMS schema definition of "receipt" to allow empty receipts is indeed better than this, and easier than changing the ebBP schema. I'm not sure if this can be argued to be an "errata" on the core V3 schema.
 
So are there any other alternatives?  In some e-business standards, acknowledgements involve including a copy of the received business document.  This is the approach of the various OAG BODs using the "Acknowledge" verb.  E.g. an AcknowledgePurchaseOrder BOD contains a PurchaseOrder structure.  In ETSI TS 102 640 (Registered Electronic Mail) there is the option to include the Original Message or a Normalized Message with a receipt, for legal reasons.  
 
For large XML messages or messages with large non-XML attachments, that seems unpractical.  So as a simplified alternative, I'm proposing that we do not use the ebBP signal but instead include the eb:UserMessage XML element of the received message.  Advantages:
1)   We don't use the ebBP element in a way that does not match its purpose and intent.
2)   No need to handle various special cases, as my previous XSLT had to.
3)   Very simple to implement in AS4 message handlers (basically one line of code to fetch the element using XPath or equivalent and another to insert it as the child node of the receipt element).
4)   The receipt actually has rich metadata about the received message, which may be of interest for testing and monitoring purposes.
5)   The receipt contains the UserMessage including Payload references, but not the actual payloads, so its size is limited.
6)   No need to change the V3 Core XSD or the ebBP schema.
 
The UserMessage element is a separate element in the "refactored" ebMS header we created in Part 2, so an AS4 engine can validate using that schema.  For consistency across reception awareness and NRR, we could include the UserMessage also in the NRR case. But the UserMessage does not contain hash values of payloads, so it is insufficient for NRR, and the ebBP NonRepudiationInformation element would still be needed.
 
I'll be in meetings the rest of the day, talk to you all tonight.
 
Pim
 
 


From: ebxml-msg@lists.oasis-open.org [mailto:ebxml-msg@lists.oasis-open.org] On Behalf Of Sander Fieten
Sent: 17 January 2012 19:58
To: ebxml-msg@lists.oasis-open.org
Subject: Re: [ebxml-msg] Groups - AS4-profile-v1.0-wd20.odt uploaded

I think that the problem here is the use of the Receipt signal [message] for reception awareness. The phrase "The eb:Receipt element MAY occur zero or one times; and, if present, SHOULD contain a single ebbpsig:NonRepudiationInformation child element" in the Core spec however suggests that the signal was designed with only non repudiation in mind. Reception awareness is than more a task of the reliability layer.

In principal reception awareness only requires a reference to the received message, and therefor the eb:Receipt itself would suffice. But that is something the ebMS schema does not allow. So another option would be to relax that requirement and make an empty Receipt element possible.  However that may take some time, but the that is also the case when requesting a change for the ebBP schema. 

Another option would be to use a different child element for eb:Receipt in case of reception awareness. Question than is which element that should be? Also it goes against the "SHOULD" from the core spec, but that would be defendable because the goal we want to achieve is not non repudiation but reception awareness. So not ideal either.

The solution as described in the current draft is, in my opinion the easiest one to implement the reception awareness case based on the current specs of both the eb:Receipt and ebbp:NonRepudiationInformation elements. I therefor favor to stick to the draft as was decided during our TC call on December 14th.


Regards,
Sander
 
 


On 17 jan. 2012, at 17:51, Pim van der Eijk wrote:

Jacques,
 
In my email to the list of December 13, there are a number of examples using MessagePartIdentifier.  There is also an XSLT that computes an AS4 receipt, with documentation, for the range of diverse situations to support. 
 
The ebBP signal assumes a receipt for a message includes information about constituent parts of a message using either XML Signature references or using a MessagePartIdentifier.  The structure seems oriented towards MIME-structured messages that have MIME part identifiers. If we are re-using this signal structure, we should stick to its structure and semantics,  beyond making sure the receipts pass XML validation.   So if a message has part identifiers (Payload references),  it seems to me that a receipt should use those part identifiers and not (just) the ebMS MessageId.
 
If we find the ebBP structure to be limiting,  we could also ask ebCore (which maintains the schema) to update the ebBP signal schema, e.g. via the Errata process. The XSLT would be much simpler if the schema would support an empty list of message parts (User Messages with no Payloads), or part identifiers that have the empty string value (for messages that have no "href" attribute, using the implicit assumption that this refers to a payload in the SOAP Body).
 
Pim


From: ebxml-msg@lists.oasis-open.org [mailto:ebxml-msg@lists.oasis-open.org] On Behalf Of Jacques Durand
Sent: 24 December 2011 02:53
To: ebxml-msg@lists.oasis-open.org
Subject: RE: [ebxml-msg] Groups - AS4-profile-v1.0-wd20.odt uploaded

I have uploaded AS4-profile-v1.0-wd21.odt. Diffs show compounded changes with wd20,  from wd19. Note:

-          5.1.8 left untouched. It strikes me we have no example of using ebbp:MessagePartIdentifier  . We should  have one at least, as this is a foreign element to ebms. Also, it does not sound right to state “The ebbp:MessagePartIdentifier element SHOULD contain the eb:MessageId of the received message.” As Pim mentioned, this is a SHOULD which does not help much. But why shouldn’t we refer to each message part, if we have to use ebbp:MessagePartIdentifier? I would expect to see in a Receipt the content of href string from the original message ( <eb:PartInfo href="">) for each part referred in the receipt.

-          I added in the AS4 additional features section, a couple of Receipt-related error codes recommended by Pim.
-jacques
From: ebxml-msg@lists.oasis-open.org [mailto:ebxml-msg@lists.oasis-open.org] On Behalf Of Jacques Durand
Sent: Wednesday, December 07, 2011 10:03 AM
To: Pim van der Eijk; ebxml-msg@lists.oasis-open.org
Subject: RE: [ebxml-msg] Groups - AS4-profile-v1.0-wd20.odt uploaded
Pim and all:
Inline , a few more comments <JD>.
I am not sure I can attend tomorrow’s meeting – will try, but am in another F2F meeting out of office.
-jacques
From: Pim van der Eijk [mailto:pvde@sonnenglanz.net] 
Sent: Tuesday, December 06, 2011 1:09 AM
To: Jacques Durand; ebxml-msg@lists.oasis-open.org
Subject: RE: [ebxml-msg] Groups - AS4-profile-v1.0-wd20.odt uploaded
Unfortunately not all changes to previous versions were tracked.
Comments inline.
Pim

From: ebxml-msg@lists.oasis-open.org [mailto:ebxml-msg@lists.oasis-open.org] On Behalf Of Jacques Durand
Sent: 05 December 2011 23:55
To: Pim van der Eijk; ebxml-msg@lists.oasis-open.org
Subject: RE: [ebxml-msg] Groups - AS4-profile-v1.0-wd20.odt uploaded

I have uploaded a candidate AS4 spec (AS4-profile-v1.0-wd20.odt) from wd19, that implements most of Pim’s recommendations, remaining from  Sander’s (in wd19).
1-     Compression property with value "true" instead of empty string for XML schema compliance.
Did the update that requires the “Compressed” property to have a value  (I believe the Example in 3.1 was the main culprit?). Also it seems we never introduced the “Compressed” property used in the example (so I did).
Section 3.1 now requires two properties "Compressed" (fixed value "true") and "CompressionType" (fixed value "application/gzip"), but the example in that section still only has "Compressed". Having a separate property for the type of Compression seems useful if more than one type is allowed (other compression algorithms have emerged after GZIP that have advantages in some cases, though it's fine if AS4 does not want to use them for interoperability), but if we have just one allowed value,  what does it add? Isn't the "Compressed" property redundant if we specify the "CompressionType" ?
<JD> I see. So the example alone was wrong. And if we have to choose between Compressed=”true” / “false” andCompressionType=”application/gzip” (no other altearnative – so far) then I’d choose to keep CompressionType=”application/gzip” because in a future version of AS4 there might be another compression option, and we don’t want to change the schema to support that. So I would not give it “true” as value, or did I misunderstand this issue?
2-     MIME type value in property for a compressed attachment required instead of recommended.
Done by Sander.
3-     Add note that a compressed payload must be in a separate MIME part and not in the SOAP Body
Added a simple note in 3.1.
4-   In AS4 5.1.8.(a) and 5.1.8.(b), clarify use of receipts with simple SOAP messages, where the SOAP envelope is not in a part with a content identifier, and has no MIME content ID, so here there can be no part identifier.   
Done by Sander.
5.1.8 (b) references message parts using ds:References, but 5.1.8 (a) now should references the ebMS message ID in a PartInfo ? The MessageId is already referenced in the eb3:RefToMessageId in the MessageInfo of the SignalMessage in both cases, having it as value for MessagePartIdentifier in one case is redundant, is inconsistent with the other non-repudiation use and does not match the semantics of the ebbp:NonRepudiationInformation structure.  
<JD> I noticed this redundancy. Should we remove that requirement? I don’t recall why we made it.
BTW what would "should" mean,  are other values allowed, if yes, which ones?
The earlier proposal was to use the MIME part identifiers for reception awareness.   This works for all SOAP with attachment messages.  The issue was about plain SOAP messages with any payload in the SOAP body.  Another solution is to require SOAP with attachments for AS4 messages (or at least for the ones that require receipts), after all that worked in ebMS 2.0. 
Unfortunately the value of a MessagePartIdentifier is a non-empty string, so it cannot be left unspecified.
5-  In AS4 5.1.8.(a) and 5.1.8.(b), note that it is impossible to generate a valid ebBP reception awareness
We have to decide what note to be added in 5.1.8 for this.
6-  In AS4 5.1.8.(a) and 5.1.8.(b), decide on ebbp:MessagePartIdentifier format for a payload part in SOAP body that is implicitly identified by absence of an "href" attribute as described in ebMS3Core.
Should we just require something like a string “soap:body”, for readability? (not done yet)
Unfortunately the value of a MessagePartIdentifier is a non-empty string, so it cannot be left unspecified. We could profile AS4 to make the href attribute mandatory, always or for messages that request receipts.
7-  Clarify that an identifier of a payload in the SOAP Body is a stored as an attribute value on the SOAP Body element, not on the contained document root (AS4 interop).
Not sure I understand this: the soap Body could have several payload parts actually, and the @id attribute is at the root of each one of these (not on the Body element). See example in Appendix C2 of Core V3.
There is a problem with that example in the core spec:  the business document is submitted by the Sending application, and it may not have an "id" attribute.   We shouldn't let the sending MSH add an id, as the receiving MSH may not know if it was added by the sending application or by the sending MSH, so it can't remove it. The XML schema of that document may not even allow an "id" attribute, so unless it were removed, the receiving application would consider it an invalid XML document.  
When using WS-Security, the identifying attribute is on the SOAP:Body, not on the enclosed XML document.  We don't require WS-Security, but the place to put the attribute should be the same whether we use it or not.
<JD> I see. Should we – as part of AS4 profile – recommend that in case several payloads are added in the Body, there should be a wrapper that will have this @id  (like <payloadpart id=…>. That’s not pretty but I don’t see how to do better…
8-  Discuss the format of the identifier (xml:id or wsu:Id).   
It seems to be @id (not @Id) see examples in core V3.
9-  Bad references to SOAP 1.1 instead of 1.2.
Done by Sander.
10-Guidelines on values for mpc (message partition channel) attributes.  Pullrequests do not have ebMS metadata, so a partner that sends documents to multiple partners using Pull mode must assign them to different channels, unless we want to require support for the "selective pulling" feature of Part 2 in ebMS.
Here I think it would be better to add as an optional extra feature  (for a Sender), support for sub-channels. We have defined this feature in Part 2 for intermediaries only. We can refer to it as an (optional) extra feature, as it was initially defined for a multi-hop context but can easily be considered in a single hop case here.. See new proposed section 3.5. 
We need a way to specify, as a new PMode parameter the "receiver sub-MPC".  This is the MPC that the receiver pulls from. It may be different from the MPC the sender submits it to, but not completely different, it is required to be a sub-channel. 
<JD> AS4 can add a new PMode parameter PMode[1].BusinessInfo.subMPCext  that must contain the extension only to be appended to the PMode[1].BusinessInfo.MPC. E.g. if MPC = http://sender.example.com/mpc123”  and subMPCext   = “subc42”, then the subchannel to pull from is: http://sender.example.com/mpc123/subc42
The Sending MSH needs to know how to partition the set of messages submitted to an MPC across various sub-MPCs.  What rules control this partitioning?  
<JD> the assignment of messages to sub-channels is done similarly to the way its described in Part 2: there is a different PMode for each subchannel receiver, so this is just like regular message-to-PMode matching.
We might associate a sub-channel with an XPath _expression_ over the UserMessage header.  Here the partitioning is done at submission time and authorization can be done at a fine-grained sub-channel level.
Another option is the selective pulling feature in Part 2.  Basically,  a receiver could pull from a generic MPC and select it using the to:PartyId=<<their ID>>.  Here the selection is done more dynamically, the receiving MSH has more control. But the receiver must be authorized for the MPC, so this is more a feature to give better control to the receiver. 
<JD> the issue with this is that there is no guarantee that your messages will NOT be pulled by unauthorized parties (as everyone is authorized the same way for selective pulling)
11-  Support for Two Way MEPs.   This is not needed for EDIINT,  but in essence allowing an MSH to set the value for RefToMessageId adds minimal complexity to an implementation.   It allows AS4 to be used also for SOA-style, request/response interactions.
I think Sander addressed this (just as an option) with a simple note.
If we want this, we need to allow them in 2.1.1 and 2.2.1. I'm in favour of allowing Two Way MEPs.   All it means is that an MSH must be able to set an eb3:RefToMessageId in an outgoing message, which is trivial.  (We require them to set ConversationId already, after all).   I can't think of any interop reasons to leave this out. The main benefit is that AS4 can be used for SOA-style, request/response interactions and not just for batch EDI.  AS4 could replace ebMS 2.0 for all of my customers' applications if it supported this.  
The OASIS Energy Interop TC is currently profiling ebMS 3.0 for smart grid, and this issue came up there are well.
IncludingRefToMessageId in responses supports a style of asynchronous programming where the sender registers a callback based on MessageId. It is possible to do this by correlating message payloads,  but it is much more practical and consistent to be able to use a UserMessage element. When the response comes it, the appropriate handler can be called before any payloads are processed.
IMPORTANT:  regarding support for compression:
-          The question whether light AS4 clients – in particular “minimal” client - should support compression (meaning also attachments, and msg properties) is still controversial in my view: if we want to “certify” very light clients and devices, I’d be in favor of keeping the “minimal client” conformance level low, i.e. not requiring these features. 
There was a questionabout this in the OASIS Energy Interop TC as well.   They asked if GZIP support is widespread or practical in low-end devices that are in their scope.   A strong advantage of GZIP is that it has a very small memory footprint and is fast (compared to other algorithms that have a better compression ratio).
They also asked if we had considered http://www.w3.org/TR/2011/REC-exi-20110310/as an alternative.
-          So my uploaded draft reflects this option (low bar for “minimal client” conformance level). See the conformance Clause: to be discussed.

NOTE: a small issue not fixed yet: the ref to V3 Part 2 is using a different acronym in the ref section ([ebMS3ADV]) than in the body of the spec (ebMSP2)

Thanks
Jacques
From: ebxml-msg@lists.oasis-open.org [mailto:ebxml-msg@lists.oasis-open.org] On Behalf Of Pim van der Eijk
Sent: Friday, November 11, 2011 6:26 AM
To: ebxml-msg@lists.oasis-open.org
Subject: [ebxml-msg] Groups - AS4-Profile-csd04-wd-17.odt uploaded
Submitter's message
I've made some updates based on discussion of the issues in the TC. Jacques will produce the next version after the upcoming F2F.

------------

Fixed a bad reference to SOAP 1.1 in section 2.2.1 . 

In 3.1 compression, the original MIME type of a compressed payload is required instead of just being recommended; added clarification on use of CharacterSet in compression.

Minor editorial changes and some comments on areas that may need clarification.

-- Mr. Pim van der Eijk

Document Name: AS4-Profile-csd04-wd-17.odt


Description
AS4 profile 
Download Latest Revision
Public Download Link


Submitter: Mr. Pim van der Eijk
Group: OASIS ebXML Messaging Services TC
Folder: documents
Date submitted: 2011-11-11 06:25:55
Revision: 12




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