The TaskAction: Triggering a Task from the Sitemap

To invoke a task from a sitemap pipeline, you use a TaskAction. The task ID is handled to the action by a task parameter:

<map:components>
  ...
  <map:actions>
    <map:action name="publisher"
                src="org.lenya.cms.cocoon.acting.TaskAction">
      <task id="publish"/>
    </map:action>
  </map:actions>
  ...
</map:components>

The TaskAction collects the request parameters and forwards them to the task.

<map:match pattern="lenya/publish*">
  <map:act type="publisher">
    <map:redirect-to uri="{parent_uri}" session="true"/>
  </map:act>
  <map:redirect-to uri="publishScreen?status=failed" session="true"/>
</map:match>

You can also pass the task ID as a task-id parameter directly in the pipeline:

<map:actions>
  <map:action name="task" src="org.lenya.cms.cocoon.acting.TaskAction"/>
</map:actions>

...

<map:match pattern="lenya/publish*">
  <map:act type="task">
    <map:parameter name="task-id" value="publish-article"/>
    <map:redirect-to uri="{parent_uri}" session="true"/>
  </map:act>
  <map:redirect-to uri="publishScreen?status=failed" session="true"/>
</map:match>

See section Scheduler.

Every task must implement the org.lenya.cms.task.Task interface.

The easiest way to develop your own task is to extend the AbstractTask class. Its parameterize() method simply replaces old parameter values with new ones. All you have to do is implementing the execute(String contextPath) method.

You may wonder why we pass the contextPath as a method parameter since we already pass it as a task parameter. This ensures that the task is always able to access the Lenya CMS directory, even if it is not created by a TaskAction or a TaskJob. Furthermore, if you enter a task in the jobs.xml file manually, you won't have to provide a hard-coded servlet-context parameter.

This feature may be subject to changes. If you have any suggestions to improve the task implementation, just contact me (Andreas Hartmann) at ah@wyona.org.