Step4.md

Step 4

• Change the calculation from step 3 to return the result of the calculation and return the result as json

  • Create a case class to represent the calculation domain, e.g.

case CalculatedSum(a: Int, b: Int, sum: Int)

• Add spray-json dependency by adding this line to build.sbt:

"io.spray" %% "spray-json" % "1.2.5"

• Type reload in sbt to reload the sbt configuration or just restart sbt manually

• Write a JsonFormat for the domain model to make it able to automatically convert to json

  object CalculatedSum {
    import spray.json.DefaultJsonProtocol._
    implicit val sumJsonFormat = jsonFormat3(CalculatedSum.apply _)
  }

• Add an import to SprayJsonSupport:

import spray.httpx.SprayJsonSupport._

• In the calculation route, complete the request with the domain model directly

complete(CalculatedSum(a, b, a + b))

• View the result in the browser

• (Write tests to check the behavior)