Get tweets from API using Akka-HTTP, Twitter4j - scala

Question

I have methods which get tweets by userid, I used Twitter4J and Akka streams for that. I want to create an API in such a way that the user send get request and receives a set of tweets. The request would look like this:
http://localhost:8080/tweets/534563976
For now, I can only get Ok status, but I do not know how to get tweets through some client like Postman (when I send get request). As I get all the tweets only on my console. My API route looks like this:
trait ApiRoute extends Databases {
val twitterStream = TwitterStreamFilters.configureTwitterStream()
val counter = new Counter
twitterStream.addListener(counter)
val routes = pathPrefix("tweets") {
pathSingleSlash {
complete("hello")
}
} ~
pathPrefix("tweets") {
pathPrefix(LongNumber) {
userId =>
get {
onSuccess(Future.successful(TwitterStreamFilters.filterTwitterStreamByUserID(twitterStream, Array(userId)))) {
complete(StatusCodes.OK)
}
}
}
}
}
But I would like to change it to something like this,. But when I write this I get TypeMismatch, expected:ToResponseMarshallable, actual:RequestContext compilation error:
onSuccess(Future.successful(TwitterStreamFilters.filterTwitterStreamByUserID(twitterStream, Array(userId)))) {
result => complete(result)
}
This is the method of filtering tweets:
def filterTwitterStreamByUserID(twitterStream: TwitterStream, userId: Array[Long]) = {
twitterStream.filter(new FilterQuery().follow(userId))
}
Here is my code to acquire a stream of tweets:
class Counter extends StatusAdapter{
implicit val system = ActorSystem("EmojiTrends")
implicit val materializer = ActorMaterializer()
implicit val executionContext = system.dispatcher
implicit val LoggingAdapter =
Logging(system, classOf[Counter])
val overflowStrategy = OverflowStrategy.backpressure
val bufferSize = 1000
val statusSource = Source.queue[Status](
bufferSize,
overflowStrategy
)
val sink: Sink[Any, Future[Done]] = Sink.foreach(println)
val flow: Flow[Status, String, NotUsed] = Flow[Status].map(status => status.getText)
val graph = statusSource via flow to sink
val queue = graph.run()
override def onStatus(status: Status) =
Await.result(queue.offer(status), Duration.Inf)
}
So how I change my API method call or the filtering method itself to get a set of tweets as a response to my get request? Or better to say how to redirect them to from console to the response body? Should I use a database for that?
Any advice is appreciated!

Answer 1

Match the result of onSuccess:
onSuccess(Future.successful(TwitterStreamFilters.filterTwitterStreamByUserID(twitterStream, Array(userId)))) {
case tweets: Set[Tweet] => complete(StatusCodes.OK, tweets)
}
Of course, you will have to provide a response marshaller. If you want to have a JSON as response, you can use Akka HTTP JSON + Circe. Just add these two imports and it should work if you don't have some special types in response class (e.g. Tweet):
import de.heikoseeberger.akkahttpcirce.FailFastCirceSupport._
import io.circe.generic.auto._