RE: XML Messaging

[David Burdett <david.burdett@commerceone.com>]

Some responses to Nikola's questions.
 
REQUIREMENTS FOR XML MESSAGING
Nikola suggests that you might have an optional IncludeResponse Yes/No that
would return the original response.
 
We thought about this when developing the reliable messaging part of IOTP
and concluded that we would not include the original response on an inquiry
since it creates a security threat. For example suppose that the response
was receipt for a payment that proves the payment was made (as in IOTP),
then if anyone can get the receipt just by doing an inquiry then they might
be able to use the receipt to demand delivery of goods when they shouldn't.
 
Instead we decided the only way to get a response is to resend the
immediately preceding message. If the original conversation occured over a
secure channel like SSL then only the original sender should have access to
the previous message. 
 
The only other way to provide security would require the transaction status
inquiry request to be digitally signed transaction to ensure that the sender
was entitled to get the response. We didn't like this since it would require
use of digital signature that could otherwise have been avoided.
 
XML MESSAGING DATA ITEM
Nikola asks >>>What if Response was sent before Cancel is received? Is this
up to the implementation of the Choreography?<<<
 
When the cancel is received after the response is sent it is always treated
as being in error and results in an error message being sent back. You can't
cancel a completed transaction - it's too late.
 
Regards
 
David

-----Original Message-----
From: Nikola Stojanovic [mailto:nstojano@cjds.com]
Sent: Wednesday, March 01, 2000 6:14 AM
To: ebXML Transport (E-mail)
Subject: XML Messaging


Requirements for XML Messaging
 
4.2
 
Another recommended guideline for recovery?
 
- Carry out a Transaction Status Inquiry (TSI) for the Transaction. TSI
might have an optional IncludeResponse (Yes | No).
- If the result of the Inquiry is not ("Not Known" or "In Progress" (should
include "Not Yet Started" as well?)) then the first Message was received and
processed but the Message in Response did not get through so include the
Original Response (is it always available? if not, create another one)
within the result of the Inquiry back to the Inquirer.
 
XML Messaging Data Items

2.2.3 
 
<snip>
A Transaction can be canceled by the sender of a Request Message by sending
a Cancel Message to the same destination as the Request Message before the
Response Message for that Transaction is received.
</snip>
 
What if Response was sent before Cancel is received? Is this up to the
implementation of the Choreography?
 
Nikola