Using Spray to compose routes for different API versions

ComposeAPiVersions.scala

package test

import spray.routing.Directives._
import org.scalatest.{Matchers, FunSpec}
import spray.testkit.ScalatestRouteTest

/**
 * Routes that we can compose into our overall ReST API. The current plan
 * is to have route completion in a separate compilation unit to keep the
 * API layout easy to reason about.
 */

// API versions are layered as traits
trait RestV1_0 {

  lazy protected val user = path("user") {
    complete("user")
  }
  lazy protected val topicSearch = path("topicsearch" / Segment) { foo => complete(foo)}

  lazy protected val routeV1_0 = pathPrefix("v1_0") {
    get {
      user ~ topicSearch
    }
  }
}

// V1.1 simply extends v1.0, adds another call and retains the old calls
trait RestV1_1 extends RestV1_0 {

  lazy protected val geolocate = path("geolocate") {
    complete("geolocate")
  }

  lazy protected val routeV1_1 = pathPrefix("v1_1") {
    get {
      user ~ topicSearch ~ geolocate
    }
  }
}

// Manifest the routes here as /api/v1_1 and /api/v1_0
object VersionedRoute extends RestV1_1 {
  lazy val route = pathPrefix("api") {
    routeV1_1 ~ routeV1_0
  }
}

class RestRoutingTest extends FunSpec with ScalatestRouteTest with Matchers {

  describe("Composed API versioned example routes should") {
    it("return v1.0 calls") {
      Get("/api/v1_0/user") ~> VersionedRoute.route ~> check {
        responseAs[String] should equal("user")
      }
      Get("/api/v1_0/topicsearch/blah") ~> VersionedRoute.route ~> check {
        responseAs[String] should equal("blah")
      }
    }

    it("return v1.1 user") {
      Get("/api/v1_1/user") ~> VersionedRoute.route ~> check {
        responseAs[String] should equal("user")
      }
      Get("/api/v1_1/topicsearch/blah") ~> VersionedRoute.route ~> check {
        responseAs[String] should equal("blah")
      }
      Get("/api/v1_1/geolocate") ~> VersionedRoute.route ~> check {
        responseAs[String] should equal("geolocate")
      }
    }
  }
}