My Playframework Action Returns Before A Future Is Ready, How Do I Update A Web Page Component?

I have a Scala PlayFramework function that calls MongoDB and gets a Future[Seq[Document]] result. After a map zoom/pan event, this Play Action function is called from JavaScript

Solution 1:

Action is not designed to work with futures. Use Action.async, which will "wait" (technically not wait, but schedule) for the future to finish:

def rect(swLon: Float, swLat: Float, neLon: Float, neLat: Float) = Action.async {
  val sb = new StringBuilder()
  sb.append("<tt>boundingBox: swLon=" + swLon + ", swLat=" + swLat + ", neLon=" + neLon + ", neLat=" + neLat + "</tt>")
  if (oDb.isDefined) {
    val collection: MongoCollection[Document] = oDb.get.getCollection(collectionName)
    val fut = getFutureOne(collection) // returns a Future[Seq[Document]]
    fut.map {docs => 
      setMongoJson(doc.toJson)
      Ok(sb.toString)
    } recover {
      case e => BadRequest("FAIL: " + e.getMessage)
    }
  } else Future.successful(Ok("Not defined"))
}

Take a look at this for reference: https://www.playframework.com/documentation/2.4.x/ScalaAsync