xpur

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Module

The xpur accessor is exported by the urn:org:ten60:netkernel:ext:xml:ura module. Import this module to gain access to the accessor.

Syntax

URI

active:xpur

Argument	Rules	Description
operand	Mandatory	the resource containing a URI
operator	Mandatory	a canonical XPath document

Example Usage

DPML

<instr>
  <type>xpur</type>
  <operand>foo.xml</operand>
  <operator>
    <xpath>/path/to/uri</xpath>
  </operator>
  <target>var:uri</target>
</instr>

NetKernel Foundation API

req=context.createSubRequest("active:xpur");
req.addArgument("operand", [resource representation, aspect, or URI] );
req.addArgument("operator", [resource representation, aspect, or URI] );
result=context.issueSubRequest(req);

Purpose

The xpur accessor returns a canonical URI extracted from an XPath location in the operand document. The XPath location is supplied by the operator as a canonical XPath document.

Documents frequently contain URI's that are needed for subsequent processing. This accessor extracts the value at a given xpath location and casts it to a canonical URI.

Here's an example...

<instr>
  <type>xpur</type>
  <operand>
    <example>
      <someresource the_uri_to_my_resource="file:/some/resource.xml">
        <desc>My resource</desc>
      </someresource>
    </example>
  </operand>
  <operator>
    <xpath>/example/someresource/@the_uri_to_my_resource</xpath>
  </operator>
  <target>var:uri</target>
</instr>

Produces a value in var:uri...

<uri>file:/some/resource.xml</uri>