Gatling Request Body Processor Use Case

readme.md

Gatling provides Request Body Processor processRequestBody() to process the request body before it sent to over wire.

There are two built-in processors available but one can have their own custom processor to modify the body content before sending it to server.

Below code demonstrates an use case where I am using a text file to fetch the request body as .body(ElFileBody("payload.txt")) and modifying the _placeholder with some computer name before sending.

ConfigurableSimulation.scala

package simulation

import io.gatling.core.Predef.Simulation
import io.gatling.core.body.{Body, ByteArrayBody, CompositeByteArrayBody, InputStreamBody, PebbleBody, RawFileBody, ResourceAndCachedBytes, StringBody}
import io.gatling.core.config.GatlingConfiguration

abstract class ConfigurableSimulation extends Simulation {

  def processPayload(implicit configuration: GatlingConfiguration) : Body => StringBody =
    (body: Body) => {
      val processedBodyBytes = body match {
        case b: CompositeByteArrayBody => b.asStream.map(inputStream => {
          val actualPayload = new String(inputStream.readAllBytes())
          actualPayload.replace("_placeholder", "some computer name")
        })
      }

      StringBody(processedBodyBytes)
    }
}

payload.txt

name=_placeholder&introduced=2020-01-01&discontinued=&company=1

SampleSimulation.scala

package simulation

import io.gatling.core.Predef._
import io.gatling.http.Predef._


class SampleSimulation extends ConfigurableSimulation {

  val httpProtocol = http
    .baseUrl("https://httpdump.io")
    .acceptHeader("text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8")
    .userAgentHeader("Mozilla/5.0 (Windows NT 5.1; rv:31.0) Gecko/20100101 Firefox/31.0")


  val dumpRequestHttp = http("Dump Request Http")
    .post("/bq2lj")
    .body(ElFileBody("payload.txt"))
    .processRequestBody(processPayload)

  val scn = scenario("Dump Request")
      .exec(dumpRequestHttp)

  setUp {
    scn.inject(atOnceUsers(1))
  }.protocols(httpProtocol)
}