xrl: scheme

Home > Books > NetKernel API and Services Reference > Accessor Listing > XRL > xrl: scheme

Module

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

Example Usage

DPML

<instr>
  <comment>request info page and send to response</comment>
  <type>copy</type>
  <operand>xrl:info</operand>
  <target>this:response</target>
</instr>

In DPML, if you wish to pass arguments through to the request or specify a links file other than the default you will need to use the requestWithArgs accessor. For example:

<instr>
  <comment>request info page with a parameter of var:data and a custom links file</comment>
  <type>requestWithArgs</type>
  <uri>xrl:info</uri>
  <operator>my_links.xml</operator>
  <param>var:data</param>
  <target>this:response</target>
</instr>

NetKernel Foundation API

import org.ten60.netkernel.layer1.representation.StringAspect;
main()
{   // generate info page passing a literal string as parameter
    req=context.createSubRequest("xrl:info");
    req.addArgument("param", new StringAspect("with this param"));
    req.addArgument("operator", "links.xml");
    result = context.issueSubRequest(req);
    context.createResponseFrom(result);
}

Purpose

The xrl: scheme provides a mechanism for directly invoking internal services named in a links document. This similar to the XRL mapper but instead matches link names rather than a links external address. Like the mapper additional arguments can be attached to a request which will be passed through to the internal service subject to the limitations of the <args> specification in a link.