Pentaho PDI unable to use parameter in transformation

Question

Using Pentaho PDI 8.3.0

I am unable to use a parameter in a REST call within a transformation. What I've done is:

• Create a transformation and given it a parameter called PAGE_NR with default value 1
• Create a job
• Call the transformation with parameter PAGE_NR = 1
• In the transformation, set up a GET request to a REST API.
• In the URL field, setup the call like http://myurl.com/foo/bar?page=${PAGE_NR}

When I call this from either SoapUI or a browser it works but it always breaks when running the job. It does not seem to translate this parameter into the value, but instead passes it exactly like mentioned above.

I need this parameter because of calling the same URL but with different results. I don't know the amount of pages up front but take care of that logic later in said transformation.

Working on Linux btw. I have tried different variations of calling the parameter but nothing seems to work.

Answer 1

With the information given in the comments, I am willing to make an educated guess:

The REST Client step does not perform variable substitution on the URL if it comes from a field in the stream. What you can do is insert a Calculator step before the REST step with the operation "Variable substitution on string A" with your URL field as Field A.

This should give you the desired URL with page number.