如何将 fetchNewObject 与 update.one ReactiveMongo 一起使用? [英] How to use fetchNewObject with update.one ReactiveMongo?

问题描述

以前我使用 findAndUpdate 并且可以添加 fetchNewObject = true 所以我可以在查询之后做这样的事情:

Previously I used findAndUpdate and could add fetchNewObject = true so I was able to do something like this after the query:

.map(_.result[WhicherReport].getOrElse {
  throw new NoSuchElementException
})

但是我现在正在使用事务并且只能执行 update.one(...) 并且没有选项可以传递它 fetchNewObject，我该怎么办?

but I'm using transaction now and could only perform update.one(...) and there is no option to pass it fetchNewObject, what can I do?

这是我的功能:

  def someUpdateFunc(collection: BSONCollection, metadata: Metadata, ids: List[String]): Future[UpdateWriteResult] = {
    collection.update.one(
      q = Json.obj("metadata" -> metadata,
        notLocked(now)),
      u =  Json.obj("$set" -> Json.obj("expenses.$[elem].paired" -> true)),
      upsert = false,
      multi = false,
      arrayFilters = Seq(BSONDocument("elem.id" -> BSONDocument( "$in" -> ids))),
      collation = None)
  }

并且我想使用 ReactiveMongo 返回新的更新案例类.

and I want to return the new updated case class using ReactiveMongo.

推荐答案

没有办法将 fetchNewObject 与 update command，因为它不是此命令支持的选项.

There is no way to use fetchNewObject with an update command, as it's not an option supported by this command.

您似乎认为 findAndModify 不能用于事务，但事实并非如此:它可以与事务一起使用.

You seems to think that findAndModify cannot be used with transaction, which not the case: it can be used with transaction.

for {
  ds <- db.startSession()
  dt <- ds.startTransaction(None)

  coll = dt.collection(colName)
  _ <- coll.findAndUpdate(selector, james, upsert = true)
} yield ...

如果您出于未提及的原因仍想使用update，则需要在同一事务中之后执行find.

If you still want to use update for unmentioned reason, then you will need to execute a find after, in the same transaction.

附言.getOrElse { throw new NoSuchElementException } 是一种代码异味，应该劝阻(而是撰写).

P.S. .getOrElse { throw new NoSuchElementException } is quite a code smell, which should be discouraged (and rather compose).

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