Futures-based authorize spray directive

FutureSecurityDirectives

import scala.language.implicitConversions
import spray.routing._
import spray.routing.directives.BasicDirectives._
import spray.routing.directives._
import scala.concurrent.{ExecutionContext, Future}
import FutureDirectives._

trait FutureSecurityDirectives extends SecurityDirectives {
  def futureAuthorize(check: AuthorizeMagnet): Directive0 = check.directive
}

class AuthorizeMagnet(authDirective: Directive1[Boolean])(implicit executor: ExecutionContext) extends SecurityDirectives{
  val directive: Directive0 = authDirective.flatMap(authorize(_))
}

object AuthorizeMagnet {
  implicit def fromFutureAuth(auth: => Future[Boolean])(implicit executor: ExecutionContext): AuthorizeMagnet =
    new AuthorizeMagnet(onSuccess(auth))

  implicit def fromFutureAuthWithCtx(auth: RequestContext => Future[Boolean])(implicit executor: ExecutionContext): AuthorizeMagnet =
    new AuthorizeMagnet(extract(auth).flatMap(onSuccess(_)))
}

Usage:

def canModifyUser(u : String): Future[Boolean] = Future { .... }

val route = 
  path("users" / Segment) { user =>
    post {
      futureAuthorize(canModifyUser(user)) { 
        complete {
          modifyUser(...)
        }
      }
    }
  }