TokenAuthenticator with implicit Session

notworking.scala

trait TokenAuthenticator {
  def apiTokenAuth(implicit dbSession: Session) = new ApiTokenAuthenticator()
}

class ApiTokenAuthenticator(implicit val dbSession: Session, implicit val executionContext: ExecutionContext) extends HttpAuthenticator[User] {
  override def getChallengeHeaders(httpRequest: HttpRequest): List[HttpHeader] =
    `WWW-Authenticate`(HttpChallenge(scheme = "Token", realm = "Manta", params = Map.empty)) :: Nil

  override def authenticate(credentials: Option[HttpCredentials], ctx: RequestContext): Future[Option[User]] =
    Future.successful(
      credentials.flatMap {
        case GenericHttpCredentials(scheme, token, params) if scheme == "Token" =>  {
          Users.authenticateWithToken(token)
        }
        case _ => None
      }
    )
}