Composing Dependent Futures

DependentFutures.scala

// filter out empty options and unbox
def transform[T](fut: Future[Option[T]]): Future[T] = {
  fut.filter(_.isDefined).map(_.get)
}

val result = for (
  foo <- transform(fooService.get(1));
  bar <- transform(barService.get(foo.barId));
  quux <- transform(quuxService.get(bar.quuxId))
) yield(Ok("Quux = " + quux))

// If future is empty return not found, other errors result in internal server error
result recover {
  case e: NoSuchElementException => NotFound
  case _ => InternalServerError
}