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Akka Stream operator to split a stream by type
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import akka.NotUsed | |
import akka.http.scaladsl.model.ws | |
import akka.http.scaladsl.model.ws.{BinaryMessage, Message, TextMessage} | |
import akka.stream.scaladsl.{Broadcast, Flow, GraphDSL} | |
import akka.stream.{FanOutShape, Graph, Outlet} | |
import scala.collection.immutable | |
/** | |
* Partition websocket messages into binary and text messages. | |
* | |
* The flow takes websocket message and partitions them into two outlets, one | |
* for binary messages, the other for text messages. | |
*/ | |
object MessageByType { | |
def apply(): Graph[Shape, NotUsed] = | |
GraphDSL.create() { implicit b => | |
import GraphDSL.Implicits._ | |
val bcast = b.add(Broadcast[ws.Message](2)) | |
val collectText = b.add(Flow[ws.Message].collectType[ws.TextMessage]) | |
val collectBinary = b.add(Flow[ws.Message].collectType[ws.BinaryMessage]) | |
bcast.out(0) ~> collectBinary.in | |
bcast.out(1) ~> collectText.in | |
new Shape( | |
FanOutShape | |
.Ports( | |
bcast.in, | |
immutable.Seq(collectText.out, collectBinary.out) | |
) | |
) | |
} | |
/** | |
* Shape of the partition by type graph. | |
*/ | |
class Shape(init: FanOutShape.Init[ws.Message] = FanOutShape.Name("MessageByType")) | |
extends FanOutShape[ws.Message](init) { | |
override protected def construct(init: FanOutShape.Init[Message]): FanOutShape[Message] = | |
new Shape(init) | |
val textOut: Outlet[TextMessage] = newOutlet[ws.TextMessage]("textOut") | |
val binaryOut: Outlet[BinaryMessage] = newOutlet[ws.BinaryMessage]("binaryOut") | |
} | |
} |
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