I may have misunderstood what you want to achieve, but you don't have to
use actors if you'd prefer to just use akka-http / akka-streams. As long as
you can provide the data you want to broadcast in the form of an
akka-streams Source, it is straightforward to connect that to websocket
clients via a broadcast hub:
http://doc.akka.io/docs/akka/current/java/stream/stream-dynamic.html#Using_the_BroadcastHub
Something like the following works - in Scala, but Java code will be
similar:
import akka.NotUsed
import akka.actor.ActorSystem
import akka.http.scaladsl.Http
import akka.http.scaladsl.model.ws.{Message, TextMessage}
import akka.http.scaladsl.server.Directives._
import akka.stream.{ActorMaterializer, ThrottleMode}
import akka.stream.scaladsl.{BroadcastHub, Flow, Keep, RunnableGraph, Sink,
Source}
import scala.collection.immutable.Seq
import scala.concurrent.duration._
object Tester extends App {
implicit val system = ActorSystem("Server")
implicit val mat = ActorMaterializer()
// The source to broadcast (just ints for simplicity)
private val dataSource = Source(1 to 1000).throttle(1, 1.second, 1,
ThrottleMode.Shaping).map(_.toString)
// Go via BroadcastHub to allow multiple clients to connect
val runnableGraph: RunnableGraph[Source[String, NotUsed]] =
dataSource.toMat(BroadcastHub.sink(bufferSize = 256))(Keep.right)
val producer: Source[String, NotUsed] = runnableGraph.run()
// Optional - add sink to avoid backpressuring the original flow when no
clients are attached
producer.runWith(Sink.ignore)
private val wsHandler: Flow[Message, Message, NotUsed] =
Flow[Message]
.mapConcat(_ ⇒ Seq.empty[String]) // Ignore any data sent from the client
.merge(producer) // Stream the data we want to the client
.map(l => TextMessage(l.toString))
val route =
path("ws") {
handleWebSocketMessages(wsHandler)
}
val port = 8080
println("Starting up route")
Http().bindAndHandle(route, "0.0.0.0", port)
println(s"Started HTTP server on port $port")
}
If you run the following and connect to ws://localhost:8080/ws you'll see
the Ints being output. If you connect a second client, it will also output
the same values as the original starting from where the source was up to at
the point of connection.
HTH,
Julian
On Friday, April 21, 2017 at 10:38:11 PM UTC+1, Andrew Schenck wrote:
>
> I also found out I can simply do PubRef.tell(msg) and it will send the
> message to the client. So this is pretty much what that one post described.
> Just wanted to make sure if anyone came across this issue they had all the
> information I've found.
>
>
>
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