Wen-Hsin Hsieh Wen-Hsin Hsieh - 14 days ago 16
Scala Question

Get the return value of reactivemongo findAndUpdate function

I call the findAndUpdate function on a mongo collection to increase a counter, and I want to get the value of the counter for further use.Here is my code:

collection.findAndUpdate(
BSONDocument("name" -> "counter"),
BSONDocument("$inc" -> BSONDocument("count" -> 1)),
fetchNewObject = true,
upsert = true
).map{ e =>
println("count = " + e.value.getAs[Int]("count"))
//I want to do something with the count here
}


This doesn't compile because
e.value.getAs[Int]("count")
seems to be wrong.
The compile error is:

value getAs is not a member of Option[service.this.collection.BatchCommands.FindAndModifyCommand.pack.Document]


Please kindly advise, thanks!

Answer

Try this:

case class Person(name: String, count: Int)

object Helpers { 
  def increaseCount(collection: BSONCollection): Future[Option[Int]] = {
    import collection.BatchCommands.FindAndModifyCommand.FindAndModifyResult
    implicit val reader = Macros.reader[Person]

    val resultFut: Future[FindAndModifyResult] = collection.findAndUpdate(
      BSONDocument("name" -> "James"),
      BSONDocument("$inc" -> BSONDocument("count" -> 1)),
      fetchNewObject = true,
      upsert = true
    )

    val updatedCountOpt = resultFut.map { r =>
      r.result[Person].map { p =>
        p.count
      }
    }

    updatedCountOpt
  }
}