UDP 掃描區域網路的裝置

• 首先需要在電腦上打開一個 UDP 收訊息的連接埠

• 然後發送如下 UDP 廣播內容到區域網路的 46953 連接埠

  {"ip":"電腦端的 IP 位址","port":50000} // port 為電腦端的監聽端口

• 裝置收到這個廣播後會做出如下回復到電腦的收訊息連接埠

  {
      "ip":"192.168.31.99",
      "port":"46952",
      "devname":"裝置名",
      "deviceid":"123456789012345678901234567890123456790", // 設備 UDID
      "devsn":"XXXXXXXXXXXX",                               // 設備序列號
      "devmac":"02:03:04:05:06:07",                         // 設備 WiFi MAC 地址
      "devtype":"iPhone8,1",                                // 設備型號
      "zeversion":"0.0.1.738",                              // 服務版本
      "sysversion":"9.0.2"                                  // 系統版本
  }

• 電腦端 UDP 掃描區域網路裝置範例（適用於 Python 3.x）：

  # -*- coding: utf-8 -*-
  import socket
  import json
  
  local_ip = '192.168.31.13'  # 電腦端地址
  local_port = 31500
  
  local = (local_ip, local_port)
  remote = ("255.255.255.255", 46953)
  s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
  s.bind(local)
  
  s.setsockopt(socket.SOL_SOCKET, socket.SO_BROADCAST, 1)
  s.sendto(json.dumps({"ip": local_ip, "port": local_port}).encode('utf-8'), remote)  # 編碼為 UTF-8
  
  while True:
      data, addr = s.recvfrom(2048)
      if not data:
          print("client has exited")  # 使用 print() 函數
          break
      print("received:", data, "from", addr)  # 使用 print() 函數
  
  s.close()

• 電腦端 UDP 掃描區域網路裝置範例（適用於 Node.js）：

  var http = require('http');            //HTTP 服務
  
  var dgram = require('dgram');        //UDP 模塊
  var server_Port = 31500;            //服務端口
  var client_Port = 31501;            //發信端口
  
  var device_List = {};                //設備列表
  
  //創建收信服務
  var server_Socket = dgram.createSocket('udp4');
  server_Socket.on('message', function(msg, rinfo){
      console.log('收到消息：%s', msg);
      var device_Info = JSON.parse(msg)
      //過濾重復
      if(device_Info.deviceid){
          device_List[device_Info.deviceid] = device_Info;
      }
  });
  server_Socket.bind(server_Port);
  
  //創建發信服務
  var client_Socket = dgram.createSocket('udp4');
  client_Socket.bind(client_Port);
  
  var search = function(){
      var server_List = new Array();
      var os = require('os');
      var ifaces = os.networkInterfaces();
      for (var dev in ifaces) {
          var alias = 0;
          ifaces[dev].forEach(function(details){
              if (details.family=='IPv4') {
                  server_List.push(details.address);
                  ++alias;
              }
          });
      };
      for(var address in server_List) {
          var ip_ar = server_List[address].split(".");
          var send2ip = ip_ar[0] + "." + ip_ar[1] + "." + ip_ar[2] + ".255";
          var client_Socket = dgram.createSocket('udp4');
          var msg = JSON.stringify({ip: server_List[address], port: server_Port});
          client_Socket.send(msg, 0, msg.length, 46953, send2ip);
      };
  }
  
  http.createServer(function (request, response) {
      response.writeHead(200, {'Content-Type': 'application/json'});
      search()
      response.end(
          JSON.stringify(device_List)
      );
  }).listen(22222);
  search()
  console.log('Web 服务地址：http://127.0.0.1:22222/');