Gatling Evaluate Expression Language - scala

Question

Gatling parses Strings parameter values and turn them into functions that will compute a result based on the data stored into the Session when they will be evaluated.
Gatling Documentation
Is there any way to do this manually in an exec?
I have multiple request body templates which use EL attributes, the request sent will differ based on a feeder
The code I currently have is as such:
// Body itself contains attributes say ${uuid}
val body1 = Source.fromResource("body1.json")
val body2 = Source.fromResource("body2.json")
val scn: ScenarioBuilder = scenario("Dynamic body")
.feed(feeder)
.exec(session => {
if(session("requestType").as[String].equals("first"))
session.set("request", body1)
else
session.set("request", body2)
session
}
.exec(http("Http Call")
.post(url)
.body(StringBody("${request}"))
// This won't evaluate the nested attribute and body will remain ${uuid} instead of an actual UUID
)
I expect that there won't be a way to evaluate nested EL attributes, but is there a way to manually evaluate it using session variables? Something along the lines of
.exec(session => {
val evaluatedBody = merge(body1, session)
session("request", evaluatedBody)
session
})
I've seen ELCompiler being referenced in some other questions, but not sure where to import it from and how to use it with session values

Answer 1

You should use ElFileBody that takes a file path parameter, which can be a function.
val scn = scenario("Dynamic body")
.feed(feeder)
.exec(http("Http Call")
.post(url)
.body(
ElFileBody(session =>
session("requestType").as[String] match {
case "first" => "body1.json"
case _ => "body2.json"
}
)
)
)