Updated external user service to return email. The email is a new identifier.

app/services/AllowAllCredentialsVerificationService.scala

@@ -8,6 +8,6 @@ class AllowAllCredentialsVerificationService(app: play.api.Application) extends
     sys.error("allow-all can be used in dev mode only")
   }
 
-  override def verifyCredentials(username: String, password: String): Future[Boolean] = Future.successful(true)
+  override def verifyCredentials(username: String, password: String): Future[Either[String, String]] = Future.successful(Right(username))
 
 }

app/services/CredentialsVerificationService.scala

@@ -3,5 +3,5 @@ package services
 import scala.concurrent.Future
 
 trait CredentialsVerificationService {
-  def verifyCredentials(username: String, password: String): Future[Boolean]
+  def verifyCredentials(username: String, password: String): Future[Either[String, String]]
 }

app/services/ExternalCredentialsVerificationService.scala

@@ -5,12 +5,18 @@ import play.api.libs.ws.{WS, WSClient}
 
 import scala.concurrent.{Future, ExecutionContext}
 
+case class LoginResponse(error: Option[String], email: Option[String])
+
 class ExternalCredentialsVerificationService(url: String)(implicit executionContext: ExecutionContext, wSClient: WSClient) extends CredentialsVerificationService{
-  override def verifyCredentials(username: String, password: String): Future[Boolean] = {
+
+  private implicit val loginResponseFormat = Json.format[LoginResponse]
+
+  override def verifyCredentials(username: String, password: String): Future[Either[String, String]] = {
     WS.clientUrl(url).post(Json.toJson(Map("username" -> username, "password" -> password))).map{ response =>
-      response.body match {
-        case "OK" => true
-        case "bad" => false
+      val loginResponse = loginResponseFormat.reads(response.json).get
+      loginResponse.error match {
+        case Some(err) => Left(err)
+        case None => Right(loginResponse.email.get)
       }
     }
   }