Novell Documentation: Novell Nsure Identity Manager Driver Kit

8.5 Event Transformation Rules

Event transformation rules change an event from one type to another. They are processed in a slightly different order according to the channel, but the names of the attributes and classes are in the eDirectory name space.

There are no required transformations that an event transformation style sheet must perform. They can be used for the following:

Another XML element. For example, it can change a <delete> element to a <remove-association> element.
An XML element to an external application element. For example, if the external application has an XML interface, the <add> element could be converted to the external application's XML <create> element. This type of transformation can only be done for the subscriber as commands come from the DirXML engine and the driver passes them to the external application.
An external application element to an eDirectory XML element. For example, if the external application has an XML interface, the external application's XML <create> element could be converted to the <add> element. This type of transformation can only be done for the publisher as events come from the external application and the driver passes them to the DirXML engine.
Additional elements. For example, an <add> element could be split into an <add> and a <modify> element.
Remove elements. For example, <add> and <modify> elements could be combined into just an <add> element.
Custom command. If the external application does not have an XML interface, the XML elements could be transformed directly to a function or method from the application's interface.

The DirXML engine processes the event transformation rule according to the channel:

For the subscriber channel which sends events from eDirectory to the driver, the engine applies the event transformation rules before any of the other rules or output style sheets.
For the publisher channel which sends events from the driver to the engine, the engine applies the event transformation after the input transformation rules and the schema mapping rules, but before the matching, create, and placement rules.

The event transformation rules are kept in an DirXML-Rule object and associated with your driver through the DirXML-EventTransformationRule attribute of your driver's DirXML-Publisher and DirXML-Subscriber objects.

8.5.1 Sample Event Transformation Rule

The following sample is and event transformation for the subscriber channel that limits the scope of events.

  <?xml version="1.0" encoding="UTF-8"?><!--
       This stylesheet is and event transformation for the
       subscriber channel that limits the scope of events.
  -->
  <xsl:transform version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
  
       <xsl:template match="input/*[@src-dn]">		
            <xsl:variable name="src-dn" select="string(@src-dn)"/>
            <xsl:if test=	"starts-with($src-dn,’\TREE\novell\Provo\’) or
                     starts-with($src-dn,’\TREE\novell\San Jose\’) or
                     						starts-with($src-dn,’\TREE\novell\Orem\’) or
                     						starts-with($src-dn,’\TREE\novell\Unknown Location\’) ">
            		<xsl:copy>
                  <xsl:apply-templates select="@*|node()"/>
            		</xsl:copy>
            		</xsl:if>
       </xsl:template>
  
  <!-- identity template for everything we don’t specifically handle -->
       <xsl:template match="node()|@*">
            		<xsl:copy>
                    			<xsl:apply-templates select="@*|node()"/>
            		</xsl:copy>
       	</xsl:template>
  
  </xsl:transform>