將Scala Future轉換為Twitter Future

Question

我使用Finagle作為Web服務器，我想從我的應用程序邏輯返回Scala-Futures。 如何將scala.concurrent.Future轉換為com.twitter.util.Future，當然是以非阻塞的方式？

Answer 1

沒有足夠的環境來測試這個，但這里是我寫的"com.twitter" %% "finagle-http" % "6.25.0" ：

import com.twitter.{util => twitter}
import scala.concurrent.{ExecutionContext, Promise, Future}
import scala.util.{Failure, Success, Try}
import language.implicitConversions

object TwitterConverters {
  implicit def scalaToTwitterTry[T](t: Try[T]): twitter.Try[T] = t match {
    case Success(r) => twitter.Return(r)
    case Failure(ex) => twitter.Throw(ex)
  }

  implicit def twitterToScalaTry[T](t: twitter.Try[T]): Try[T] = t match {
    case twitter.Return(r) => Success(r)
    case twitter.Throw(ex) => Failure(ex)
  }

  implicit def scalaToTwitterFuture[T](f: Future[T])(implicit ec: ExecutionContext): twitter.Future[T] = {
    val promise = twitter.Promise[T]()
    f.onComplete(promise update _)
    promise
  }

  implicit def twitterToScalaFuture[T](f: twitter.Future[T]): Future[T] = {
    val promise = Promise[T]()
    f.respond(promise complete _)
    promise.future
  }
}

Answer 2

也可以使用Twitter bijections庫： https ： //github.com/twitter/bijection

即com.twitter.bijection.twitter_util.UtilBijections （ https://github.com/twitter/bijection/blob/develop/bijection-util/src/main/scala/com/twitter/bijection/twitter_util/UtilBijections.scala ）

此庫處理重要的細節，例如，如果您前后轉換對象，它只是解開原始對象。

Answer 3

以下是使用twitter雙向庫的示例：

import scala.concurrent.{Future => ScalaFuture}
import com.twitter.util.{Future => TwitterFuture}

// extend values by adding the conversion method "as"
import com.twitter.bijection.Conversion.asMethod

// pull in various implicit converters that "as" expects, 
// including twitter2ScalaFuture:
import com.twitter.bijection.twitter_util.UtilBijections._

def doSomething: ScalaFuture[T] = {
    val response: TwitterFuture[T] = ???
    response.as[ScalaFuture[T]]
}