How to write an asynchronous code that Awaited concisely? - scala

Question

I'm a beginner in Scala.
Please let me know if there is a more concise part in the code below.
To supplement, I'd like to call each Future method synchronously.
◆getUser method:
def getUser: Option[User] = {
Await.ready(
twitterService.getUser(configService.getString(TWITTER_USERNAME_CONF)),
Duration.Inf)
.value
.flatMap(x => Option(x.getOrElse(null)))
}
◆ process method:
def process : Unit =
for {
user <- getUser
} yield {
Await.ready(
twitterService.delete(user.id, configService.getString(TWITTER_SEARCH_KEYWORD)),
Duration.Inf)
.value
.foreach {
case Success(tweets) => tweets.foreach(tweet => println(s"Delete Successfully!!. $tweet"))
case Failure(exception) => println(s"Failed Delete.... Exception:[$exception]")
}
}

Answer 1

I made some assumptions on user and tweet data types but I would rewrite that to:
def maybeDeleteUser(userName: String, maybeUser: Option[User]): Future[String] =
maybeUser match {
case Some(user) =>
twitterService.delete(user.id, configService.getString(TWITTER_SEARCH_KEYWORD)).map {
case Failure(exception) => s"Failed Delete.... Exception:[${exception.getMessage}]"
case Success(tweets) => tweets.map(tweet => s"Delete Successfully!!. $tweet").mkString(System.lineSeparator())
}
case _ => Future.successful(s"Failed to find user $userName")
}
def getStatusLogMessage: Future[String] = {
val userName = configService.getString(TWITTER_USERNAME_CONF)
for {
maybeUser <- twitterService.getUser(configService.getString(TWITTER_USERNAME_CONF))
statusLogMessage <- maybeDeleteUser(userName, maybeUser)
} yield statusLogMessage
}
def process: Unit = {
val message = Await.result(getStatusLogMessage, Duration.Inf)
println(message)
}
That way your side effect, i.e. println is isolated and other methods can be unit tested. If you need to block the execution, do it only at the end and use map and flatMap to chain Futures if you need to order the execution of those. Also be careful with Duration.Inf, if you really need to block, then you'd want to have some defined timeout.