Re: [wsn] WSN-Policy allocations reminder

[David Hull <dmh@tibco.com>]

Why is the policy assertion to be included as a header in the Subscribe
message, and not as a child of the SubscriptionPolicy element?

Vambenepe, William N wrote:

>Hi Matt and all,
> 
>Here is my proposal, in the template provided by map, for the policy
>statement assigned to me, selection of a message subtree.
> 
> 
>Description
>
>Notification consumers might only be interested in a portion of the
>notification message. In many cases, this is handled at the consumer's
>side, by simply discarding the unwanted information. But in some cases
>(for example if the notification messages are very large and only a
>small subset is of interest to the consumer), it is advantageous to have
>the transformation take place on the notification producer's side.
>
> 
>
>For this purpose, we define a "NotificationTransformPolicy" policy
>element to advertise the fact that the notification producer provides
>the ability to transform the message before sending it.
>
> 
>
>Options
>
>The "NotificationTransformPolicy" element has the following
>pseudo-schema:
>
><NotificationTransformPolicy ...>
>
>  <SupportedDialect>xs:anyURI<SupportedDialect> +
>
>  <xs:any/> *
>
></NotificationTransformPolicy>
>
> 
>
>The "SupportedDialect" element contains a URI describing a dialect
>supported by the notification producer for transformation. The following
>dialect, "http://www.w3.org/TR/1999/REC-xpath-19991116";, represent use
>of XPath 1.0. Other dialects can be supported.
>
> 
>
>Context
>
>Support for this policy is advertised by the notification producer. This
>policy is invoked by the subscriber by placing the
>"notificationTransform" header in the subscription message. This header
>must be marked mustUnderstand=true of the consumer is not prepared to
>handle notifications that were not transformed as prescribed by the
>"notificationTransform" header.
>
> 
>
>The pseudo-schema of the "NotificationTransform" header is:
>
> 
>
><NotificationTransform
>dialect="xs:anyURI">xs:any</NotificationTransform>
>
> 
>
>The @dialect contains a URI describing the dialect used to interpret the
>value of the "NotificationTransform" element. That value can be text or
>any XML element. The "SupportedDialect" children of the
>"NotificationTransformPolicy" element indicate what dialects are
>supported by the notification producer.
>
> 
>
>If the notification message does not use the "Notify" wrapper, the
>context for the transformation is the body of the notification message.
>And the transformed message (including the "TransformedNotification"
>wrapping) is placed in the SOAP body. If the notification message uses
>the "Notify" wrapper, the context for the transformation is the
>"wsnt:Message" element. And the transformed message (including the
>"TransformedNotification" wrapping) is placed in the "wsnt:Message"
>element.
>
> 
>
>In all cases, the modified notification payload is wrapped inside a new
>element, called "TransformedNotification". There is no expectation that
>the content of the "TransformedNotification" element validate any
>schema, just that it is well-formed XML.
>
> 
>
>Example
>
>Let's assume that the following message is an example notification
>message:
>
> 
>
><s:envelope>
>
>  <!-- headers -->
>
>  <s:body>
>
>    <foo>
>
>      <bar1>bar1value</bar1>
>
>      <bar2>bar2value</bar2>
>
>    </foo>
>
>  </s:body>
>
></s:envelope>
>
> 
>
>If the subscribe message had included the following header and if this
>header was accepted by the notification producer:
>
> 
>
><NotificationTransform
>dialect="http://www.w3.org/TR/1999/REC-xpath-19991116";>/foo/bar2</Notifi
>cationTransform>
>
> 
>
>Then the notification message would instead be:
>
> 
>
><s:envelope>
>
>  <!-- headers -->
>
>  <s:body>
>
>    <TransformedNotification>
>
>      <bar2>bar2value</bar2>
>
>    </TransformedNotification>
>
>  </s:body>
>
></s:envelope>
>
> 
>
>The notifification producer can advertise the following policy element
>to communicate the fact that it supports this feature:
>
> 
>
><NotificationTransformPolicy>
>
> 
><SupportedDialect>http://www.w3.org/TR/1999/REC-xpath-19991116<Supported
>Dialect>
>
></NotificationTransformPolicy>
>
> 
>
>Regards,
>
> 
>
>William
>
> 
>
>________________________________
>
>From: Matthew I Roberts [mailto:matt.roberts@uk.ibm.com] 
>Sent: Monday, April 10, 2006 9:58 AM
>To: wsn@lists.oasis-open.org
>Subject: [wsn] WSN-Policy allocations reminder
>
>
>
>For action of;
> Rick Cobb           Durability, replay
> Matt Roberts        Managing message rates
> Martin Chapman      Boxcarring to conserve bandwidth
> David Hull          Advertising continuity support
> William Vambenepe   Selection of subtree from large message
> Lily Liu            Establishing QoS 
>
>
>As per our discussion on today's WSN conference call, here is a gentle
>reminder of the initial Policy document allocations that I made before
>Christmas. 
>
>The following link shows the original suggestions; 
> 
>http://www.oasis-open.org/apps/org/workgroup/wsn/email/archives/200512/m
>sg00040.html 
>
>This link points to the draft Policy document that shows the structure
>for the text you are preparing; 
> 
>http://www.oasis-open.org/apps/org/workgroup/wsn/download.php/15959/wsn-
>WS-NotificationPolicy-1.3-draft-01a.doc 
>
>I have provided some text for the item I was allocated in the following
>email, which you can use to get an idea of the kind of details we are
>after; 
> 
>http://www.oasis-open.org/apps/org/workgroup/wsn/email/archives/200602/m
>sg00005.html 
>
>
>Thanks in advance, 
>
>Matt 
>
>
>Matt Roberts
>IBM WebSphere Messaging Design and Development
>Hursley Park, England. +44 1962 815444
>matt.roberts@uk.ibm.com
>MP 211 / DE3H22
>
>
>  
>