unable to get the value of enumerator in Play 2.5 websocktes - scala

Question

package controllers
import javax.inject._
import play.api._
import play.api.mvc._
import play.api.libs.json._
import play.api.libs.streams._
import akka.stream._
import akka.actor._
import akka.actor.Actor
import akka.actor.ActorSystem
import akka.actor.ActorRef
import akka.actor.Props
import akka.pattern.ask
import akka.util.Timeout
import akka.actor.PoisonPill
import scala.concurrent.duration._
import akka.stream.Materializer
import play.api.cache._
import play.api.libs.iteratee._
import play.api.libs.concurrent.Execution.Implicits.defaultContext
import play.api.libs.concurrent._
import play.api.libs.ws.WSClient
/**
* This controller creates an `Action` to handle HTTP requests to the
* application's home page.
*/
#Singleton
class HomeController #Inject() (cache:CacheApi) (implicit actorSystem:ActorSystem , materializer:Materializer) extends Controller {
def validate(receivedMsg:JsValue,outChannel:Concurrent.Channel[JsValue], privateChannel:Concurrent.Channel[JsValue],outEnumerator:Enumerator[JsValue],privateEnumerator:Enumerator[JsValue]) = {
val user_key = (receivedMsg \ "username").get
val username = user_key.toString().stripSuffix("\"").stripPrefix("\"")
val validate_user :Option[String] = cache.get[String](username)
val valid_result = validate_user.toString()
if(valid_result.equals("None")) {
//cache is not set
// println(valid_result)
//add user
cache.set(username,username)
Ok.withSession(username->username)
//notify all users
val successMsg = Json.parse("""{"username":"Server","message":"A new user has been connected"}""")
outChannel.push(successMsg)
(outEnumerator)
}
else{
//cache is already set
//send error msg to new user
val errorMsg = Json.parse("""{"username":"Server","message":"This username is already taken"}""")
// val (privateEnumerator,privateChannel) = Concurrent.broadcast[JsValue]
privateChannel.push(errorMsg)
(privateEnumerator)
}
}
val (outEnumerator,outChannel) = Concurrent.broadcast[JsValue]; //public stuff
def socket = WebSocket.using[JsValue] {
request => {
val (privateEnumerator,privateChannel) = Concurrent.broadcast[JsValue]
var enumerator = privateEnumerator
var ret = 1;
val inIteratee: Iteratee[JsValue, Unit] = Iteratee.foreach[JsValue](receivedMsg => {
enumerator = validate(receivedMsg,outChannel,privateChannel,outEnumerator,privateEnumerator)
})
(inIteratee, enumerator)
}
}
}
I am new to scala and Play webSockets . I am working in play 2.5.3. Above depending upon the situation , i am trying to get the enumerator of private channel or public channel(i.e. for all connected users). But even if it returns it correctly, i couldn't get it in here (iteratee,enumerator). What am i doing wrong?

Answer 1

Second answer of this post (Broadcasting messages in Play Framework WebSockets) does the same thing.
Create an actor say UserManagerActor who sole purpose is to manage the users and maintain them.
UserManagerActor calls broadcast.
val (enumerator, channel) = Concurrent.broadcast[String].
channel helps in broadcasting the messages to all the users can once using the push method.
Now the actor can manage state of the users in a Map
val users = Map[String, (Enumerator[String],Channel[String])]()
Ensure the actor is killed once all users get disconnected.
Use Iteratee to know is the user is disconnected
Also remove disconnected users to keep the size of the Map manageable.