Multicast Server Clojure

multicast

(ns demo.sample
  (:require [clojure.core.async :as async])
  (:import (java.net InetAddress DatagramPacket DatagramSocket MulticastSocket NetworkInterface InetSocketAddress)))

(defonce udp-server (atom nil))
(defonce udp-client (atom nil))

(def port 5555)

(comment defn server-host [] (InetAddress/getLocalHost))

(def multicast-group (InetAddress/getByName "228.5.6.7"))

(defn create-udp-server []
  (let [socket (MulticastSocket. port)]
    (.joinGroup socket (InetSocketAddress. "228.5.6.7" port) (NetworkInterface/getByName "en0"))
    socket))

(defn create-udp-client [] (DatagramSocket.))

(defn message [text]
  (DatagramPacket. (.getBytes text)
                   (.length text)
                   multicast-group
                   port))

(defn send-message [text]
  (.send @udp-client (message text)))

(defn start-udp-client []
  (reset! udp-client (create-udp-client)))

(defn stop-udp-client []
  (.close @udp-client)
  (reset! udp-client nil))


(defn start-udp-server []
  (reset! udp-server (create-udp-server)))

(defn stop-udp-server []
  (.leaveGroup @udp-server multicast-group)
  (.close @udp-server)
  (reset! udp-server nil))

(defn empty-message [n]
  (new DatagramPacket (byte-array n) n))

(defonce counter (atom 0))

(defn start-print-loop []
  (async/go-loop []
    (let [orig-packet (empty-message 1024)]
      (.receive @udp-server orig-packet)
      (comment .send @udp-server orig-packet)
      (let [data (.getData orig-packet)]
        ; so you can stop repl and play with messages
        (swap! counter inc)))
        ;(println (String. (.getData orig-packet) 0 (.getLength orig-packet) "UTF-8"))))
    (recur)))