debasishg

val c1 = new PubSubClient("foo", r)
c1.start
val c2 = new PubSubClient("bar", t)
c2.start
val server = new PubSubServer
server.start

server ! Subscribe(c1, List("a", "b", "c"))
server ! Publish(c2, "a", "hello")
server ! Publish(c2, "c", "hi")

debasishg

object Pub {
  println("starting publishing service ..")
  val p = new Publisher(new RedisClient("localhost", 6379))
  p.start

  def publish(channel: String, message: String) = {
    p ! Publish(channel, message)
  }
}

debasishg

class Publisher(client: RedisClient) extends Actor {
  def receive = {
    case Publish(channel, message) =>
      client.publish(channel, message)
      reply(true)
  }
}

debasishg

object Sub {
  println("starting subscription service ..")
  val s = new Subscriber(new RedisClient("localhost", 6379))
  s.start
  s ! Register(callback) 

  def sub(channels: String*) = {
    s ! Subscribe(channels.toArray)
  }

debasishg

sealed trait PubSubMessage
case class S(channel: String, noSubscribed: Int) extends PubSubMessage
case class U(channel: String, noSubscribed: Int) extends PubSubMessage
case class M(origChannel: String, message: String) extends PubSubMessage

debasishg

def callback(pubsub: PubSubMessage) = pubsub match {
  case S(channel, no) => println("subscribed to " + channel + " and count = " + no)
  case U(channel, no) => println("unsubscribed from " + channel + " and count = " + no)
  case M(channel, msg) => 
    msg match {
      // exit will unsubscribe from all channels and stop subscription service
      case "exit" => 
        println("unsubscribe all ..")
        r.unsubscribe

debasishg

1. Download redis from http://github.com/antirez/redis
2. build using "make"
3. Run server as ./redis-server

debasishg

1. Open a shell and set AKKA_HOME to the distribution root
2. cd $AKKA_HOME
3. sbt console
4. scala> import sample.pubsub._
5. scala> Sub.sub("a", "b") // starts Subscription server & subscribes to channels "a" and "b"

debasishg

1. Open up another shell similarly as the above and set AKKA_HOME
2. cd $AKKA_HOME
3. sbt console
4. scala> import sample.pubsub._
5. scala> Pub.publish("a", "hello") // the first shell should get the message
6. scala> Pub.publish("c", "hi") // the first shell should NOT get this message

debasishg

Open up a redis-client from where you installed redis and issue a publish command
 ./redis-cli publish a "hi there" ## the first shell should get the message