const dgram = require('dgram');
const server = dgram.createSocket('udp4');

// const local_ip = "192.168.0.xx";
const multicast_ip = "225.0.0.100"; // 這里必須是一個組播地址(D類IP地址)

server.on('close', ()=>{
  console.log('close socket');
});

server.on('listening', ()=>{
  console.log('listening...');
  server.setBroadcast(true);
  server.setMulticastTTL(128);
  server.addMembership(multicast_ip);

  setInterval(()=>{
    send_msg();
  }, 2000);
});

server.on('message', (msg, rinfo)=>{
  console.log(`receive client message from ${rinfo.address}: ${rinfo.port}: ${msg}`);
});

server.bind(); // 隨機綁定本機一個端口

function send_msg(){
  console.log('send msg');
  server.send('hi, im server...', '8062', multicast_ip);
}

const dgram = require('dgram');
var client = dgram.createSocket('udp4');

// const local_ip = '192.168.0.xx';
const multicast_ip = "225.0.0.100";  // 這里必須是一個組播地址(D類IP地址)

client.on('close', ()=>{
  console.log('client closed');
});

client.on('error', (err) =>{
  console.log('client error' + err);
});

client.on('listening', ()=>{
  console.log('client listening...');
  client.setBroadcast(true);
  client.setMulticastTTL(128);
  client.addMembership(multicast_ip);
});

client.on('message', (msg, rinfo) => {
  console.log(`receive server message from ${rinfo.address}: ${rinfo.port}: ${msg}`);
});
client.bind('8062'); // 監(jiān)聽組播數據的端口