Why doesn't variable from a csv Feeder expand?

I have a CSV feeder, defined like

val thingFeeder = csv("ThingList.csv").circular def encodeForUrl(str:String) : String = {
return URLEncoder.encode(str, StandardCharsets.UTF_8.toString)

Then I have a scenario like:

val thingSearch =
.exec(http(“Thing Search OOP”)

  • encodeForUrl(searchLocation)
  • “&query=” + encodeForUrl("${thing_query}")
  • “&key=” + encodeForUrl("${thing_key}")
    .headers(Map(“Content-Type” → “application/x-www-form-urlencoded”, “Accept” → “application/json, text/javascript”))
    .check(status.not(400), status.not(404), status.not(500))

But, when I run it, the URL is being created without expanding the variables.

What am I doing wrong, that causes the variables to not expand?

Please read the documentation, including the first warning: https://gatling.io/docs/current/session/expression_el/#expression-language

Thanks Stéphane,
That appears to be the info I needed.