Asynchronous WebSocket in Play framework

Question

I got the example below from the following post:

http://blog.tksfz.org/2012/10/12/websockets-echo-using-play-scala-and-actors-part-i/

import play.api.libs.concurrent.Akka
import play.api.Play.current // needed by Akka.future

def simpleAsyncWebSocket = WebSocket.async[String] {
  Akka.future {
    val out = Enumerator.imperative[String]()
    val in = Iteratee.foreach[String] {
      msg =>
        out.push(msg)
    }
    (in, out)
  }
}

The question here is which execution context would the code above use? I tried using it in my Play application. Hers is what I have configured for the default execution context:

play {
  akka {
    event-handlers = ["akka.event.slf4j.Slf4jEventHandler"]
    loglevel = WARNING
    actor {
      default-dispatcher = {
        fork-join-executor {
          parallelism-factor = 3.0
          parallelism-max = 256
        }
      }
    }
  }
}

How could I attach a custom execution context to the sample code above?

Answer 1

Currently the future from akka was merged with the one from scala std library so you probably should use it instead.

http://www.scala-lang.org/api/current/#scala.concurrent.Future$ <- look at the apply function:

def apply[T](body: ⇒ T)(implicit execctx: ExecutionContext): Future[T]

it takes a second parameter the execution context so you can create one in your scope (this will be your controller), make it implicit and then it will be used.

Take a look here: http://www.playframework.com/documentation/2.2.x/ScalaAsync for more examples.