Udp廣播，線程發送與接收數據

''' Udp廣播，線程發送和接收數據。   廣播的核心是bind和setsockopt　'''
#! python3
# encoding: utf-8

import socket
import threading
import time

def upd_send(udpSocket):
    ip = '<broadcast>'
    port = 51213
    room = 1
    subnet = 2
    device = 3
    i = 0
#字符串設置爲16進制使用bytes().fromhex()。   設置帶參數爲16進制，並且參數位寬爲2，不夠用0填充，使用%02x，(跟c sprintf()參數一樣格式)
    while True:
                if (i % 2 == 0):
            data = bytes().fromhex('a7a800000018000000%02x%02x000300c010d06b'%(subnet,device))
        else:
            data = bytes().fromhex('a7a8000000180000%02x%02x%02x000300c010d06b'%(room,subnet,device))
        #data = str(data,encoding = 'utf-8')
        udpSocket.sendto(data,(ip,port))
        time.sleep(5)
        i+=1
        room+=1
        subnet+=1
        device+=1


def udp_recv(udpSocket):
    while True:
        recvData = udpSocket.recv(1024);
        recvData = recvData.decode('utf-8')
        print("收到信息%s"%recvData)

def main():
    udp_send_socket = socket.socket(socket.AF_INET,socket.SOCK_DGRAM)
    udp_send_socket.bind(('',0))
    udp_send_socket.setsockopt(socket.SOL_SOCKET,socket.SO_BROADCAST,1)
    t = threading.Thread(target=upd_send,args=(udp_send_socket,))

    udp_recv_socket = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
    udp_recv_socket.bind(('',53121))
    t1 = threading.Thread(target=udp_recv,args=(udp_recv_socket,))
    t.start()
    t1.start()

if __name__ == '__main__':
    main()