from socket import *
import time

serverName = '127.0.0.1' # 服务器地址，本例中使用本机地址
serverPort = 12000 # 服务器指定的端口
clientSocket = socket(AF_INET, SOCK_DGRAM) # 创建UDP套接字，使用IPv4协议
clientSocket.settimeout(1) # 设置套接字超时值1秒

for i in range(0, 9):
    sendTime = time.time()
    message = ('Ping %d %s' % (i+1, sendTime)).encode()     # 生成数据报，编码为bytes以便发送
    
    try:
        
        ########## Begin ##########
        # 将信息发送到服务器
        clientSocket.sendto(message,(serverName,serverPort))
        # 从服务器接收信息，同时也能得到服务器地址
        modifiedMessage, serverAddress = clientSocket.recvfrom(1024) 
        ########## End ##########
    
        rtt = time.time() - sendTime # 计算往返时间
        print('Sequence %d: Reply from %s    RTT = %.3fs' % (i+1, serverName, rtt)) # 显示信息
    except Exception as e:
        print('Sequence %d: Request timed out.' % (i+1))
        
clientSocket.close() # 关闭套接字