ReactiveMongo FindAndModify Clarification

问题

I have a collection in my MongoDB database with say several keys. Now I want to update this collection with a new field. So here is what I have so far:

  def confirm(hash: String) = {

    val myDb = dbConn.db(dbName)
    val userCollection = myDb[BSONCollection]("user")

    val selector = BSONDocument(idKey -> BSONObjectID(hash))
    val modifier =  BSONDocument(
      "$set" -> BSONDocument("date" -> BSONString(now.toString)) // Line 1
    )

    val command = FindAndModify(
      userCollection.name,
      selector,
      Update(modifier, fetchNewObject = true)
    )

    myDb.command(command)
      .map { user => // Line 2
      Right(bidList)
    }.recover {
      case LastError(ok,err, code, errMsg, _) =>
        Left(ServiceError(errMsg.getOrElse("failure!")))
    }
  }

I have two problems with the above implementation:

On Line 1: Would this update the existing document with a new field called date?

On Line 2: Mapping the myDb.command(command) gives me an Option[BSONDocument], but what I'm surprised is that I have an implicit conversion in scope. So I would have expected it to return an Option[User]!

回答1:

You can have a look at .findAndUpdate and to FindAndModifyResult which provides a .result operation to get the result according available BSON readers.

val person: Future[Option[AType]] = collection.findAndUpdate(
  BSONDocument("name" -> "James"),
  BSONDocument("$set" -> BSONDocument("age" -> 17)),
  fetchNewObject = true).map(_.result[AType])

回答2:

I just spent some time looking for play-reactivemongo equivalent . Maybe this example help somebody in future.

val collectionFut: Future[JSONCollection] = reactiveMongoApi.database.map(_.collection[JSONCollection]("sale.numberingCounter"))

def updateIdx(nsId: NumberingSeriesId, month: Option[Int], year: Option[Int], value: Int): Future[Option[NumberingCounter]] = {
 val selector = Json.obj("numberingSeriesId" -> nsId, "month" -> month, "year" -> year)        
 val modifier = Json.obj("$set" -> Json.obj("idx" -> value))
    for {
      collection <- collectionFut
      writeResult <- collection.findAndUpdate(selector,modifier,upsert = true)
    } yield {
      writeResult.value.map(_.as[NumberingCounter])
    }
  }

来源：https://stackoverflow.com/questions/33307215/reactivemongo-findandmodify-clarification

标签

mongodb

reactivemongo