How can I check if Play Slick filter has returned some rows or an empty result?

Question

I have the below code which returns Future[Option[Password]]

db.run(passwords.filter {
      x => x.providerID === loginInfo.providerID && x.providerKey === loginInfo.providerKey
    }.result.headOption)

What I want to do is as in the below pseudo code:

if above query returns no results
  do nothing
else
  return new PasswordInfo(abovequeryresult.hasher, abovequeryresult.password, abovequeryresult.salt)

I am new to Scala and have no clue about this. Tried to use flatMap like in below example, but the flatMap signature for the above db.run() is different.

find(loginInfo).flatMap {
      case Some(_) => update(loginInfo, authInfo)
      case None => add(loginInfo, authInfo)
    }

I am using Play Slick version 1.1.1

Answer 1

I think your question is more related to how manipulate Futures in Scala. If your db.run code runs in an action of a Play Controller, the best option is to declare the actions as async and map the result of query to an play.api.mvc.Result. Something like this:

def someAction = Action.async {
  find(loginInfo).map {
    case Some(authInfo) => 
      update(loginInfo, authInfo)
      Ok("Updated AuthInfo")               //Return a play.api.mvc.Resul 
    case None => 
      add(loginInfo, authInfo)
      Created("CreatedAuthInfo")           //Return another play.api.mvc.Resul
  }
}

Or if you only want the result

val future = find(loginInfo)
future.onSuccess {
  case Some(authInfo) => update(loginInfo, authInfo)
  case None => add(loginInfo, authInfo)
}
Await.ready(future, Duration.Inf)