XPath Expressions in Task Definitions

The task definition file supports XPath expressions to help define the properties for each task. You can use XPath expressions in task definitions to define literal values for task properties and to define variables whose values are dynamically derived from the input data. You can also use XPath functions to manipulate data and define how data is processed. A mapper is available on the Actions tab of the Task Definition Editor to automatically generate the XPath syntax for the actions you define. For basic properties, escalations, and notifications, you can enter XPath expressions directly into the fields on the Task Definition Editor or directly into the source code.

The Task Definition Editor supports the XPath 1.0 specification in Design view. The Source view also supports XPath 2.0 expressions, which allows you to define if-then-else conditions. To use XPath expressions to retrieve data from the task input, you need to register a prefix for the XML schema file namespace in the task definition file. Once you do this, you will use the prefix in the actual XPath expressions. You can manipulate input and output data using the WLM variables: $TaskInput and $TaskOutput. For example, an expression that extracts information about the price of an item might look similar to the following:

$TaskInput:part1/ns1:price where 'ns1' is the namespace prefix you defined.