Pieces of code demonstrating Play!s WebSocket in Scala using the (relatively) low-level way.

part_of_controllers.scala

object SomeWSHandler extends WebSocketController{
    
	def handle() {
		val rs = RequestScope.current
		
		// handle new sockets
		if (request isNew) {
			outbound.send("Hello from server!")
		}

		// handle new messages in existing socket
		val newPromise = rs.remove(FutureKey)
		for(promise <- newPromise){
			promise.get match{
				case frame: WebSocketFrame => {
					if(frame isBinary){
						outbound send "binary msg: " + frame.binaryData
					}else{
						outbound send "text msg: " + frame.textData
						frame.textData match { // match commands
							case ":close!" =>
								outbound send "Bye!"
								outbound.close()
							case _ => // Other commands are silently ignored. It this line was missing, other commands would cause scala.MatchError
						}
					}
				}
				case _: WebSocketClose => println("Goodbye.")
			}
		}

		// start waiting for next message and suspend
		if (inbound isOpen) {
			val eventPromise = inbound.nextEvent
			rs(FutureKey) = eventPromise
			request.isNew = false
			throw new Invoker.Suspend(eventPromise)
		}
	}
    
}

RequestScope.scala

import play.mvc.Http.Request
import RequestScope.Variable

final class RequestScope (val request: Request){
	
	private val store = {
		val Key = "__RequestScope"
		val args = request.args
		if(args containsKey Key){
			println("load RS")
			(args get Key).asInstanceOf[collection.mutable.Map[Variable[_], Any]]
		}else{
			println("new RS")
			val map = collection.mutable.Map[Variable[_], Any]()
			args.put(Key, map)
			map
		}
	}
	
	def update[T](variable: Variable[T], value:T){
		store(variable) = value
	}

	def remove[T](variable: Variable[T]): Option[T] = {
		val removed = store remove variable
		removed.asInstanceOf[Option[T]]
	}
	
}

object RequestScope{
	
	final class Variable[T]
	
	def current = new RequestScope(Request.current())
	
}