Breaking Change for Data Link Server Workflows in Workflow 5.50

A common way to start building a data link is to use the server workflow example that is linked in the documentation as a template.  Workflow version 5.50 introduced a change that breaks one of the expressions that was used in this example.

The example has been updated as of March 2026.  But if you used the example to build a data link workflow before March 2026, and then upgraded VertiGIS Studio Workflow to version 5.50 or later, you will need to correct the expression in your workflow.

Symptom

In Web, when opening the Result Details for a feature that has a data link, an error appears.  The "Related Records" section is also missing the linked data.  If you check the server workflow logs, they will include a message like:

Unexpected Error: VertiGIS.Workflow.Runtime.Execution.Exceptions.ExpressionEvaluationException: [WF: Expression evaluation error] The given expression could not be evaluated: \"$inputFeature.result.id.toString()\". Cannot read property 'id' of null","

or:

Unexpected Error: VertiGIS.Workflow.Runtime.Execution.Exceptions.ExpressionEvaluationException: [WF: Expression evaluation error] The given expression could not be evaluated: \"$inputFeature.result.attributes\". Cannot read property 'attributes' of null","

Resolution

1. Open the data link workflow in Workflow Designer
2. Select the "Create Value" activity, which is located just below the Start node and the "Get Workflow Inputs" activity
3. In the right-side panel, change the "Expression" input's value from =$getWorkflowInputs.inputs.context.first to =$getWorkflowInputs.inputs.context[0]
4. Save the changes, and test your data link in Web Designer