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我正在尝试实现停止和等待算法。我在发件人处实施超时时遇到问题。在等待接收者的 ACK 时,我正在使用 recvfrom() 函数。但是,这会使程序空闲,我无法按照超时重新传输。

这是我的代码:

import socket

import time

mysocket=socket.socket(socket.AF_INET,socket.SOCK_DGRAM)


while True:


   ACK= " "

    userIn=raw_input()
    if not userIn : break
    mysocket.sendto(userIn, ('127.0.0.01', 88))     
    ACK, address = mysocket.recvfrom(1024)    #the prog. is idle waiting for ACK
    future=time.time()+0.5   
    while True:
            if time.time() > future:
                    mysocket.sendto(userIn, ('127.0.0.01', 88))
                    future=time.time()+0.5
            if (ACK!=" "):
                    print ACK
                    break 
mysocket.close()
4

1 回答 1

3

套接字默认阻塞。使用套接字函数 setblocking() 或 settimeout() 来控制此行为。

如果你想做你自己的时间。

mysocket.setblocking(0)
ACK, address = mysocket.recvfrom(1024)

但我会做类似的事情

import socket

mysocket = socket.socket(socket.AF_INET,socket.SOCK_DGRAM)
mysocket.settimeout(0.5)
dest = ('127.0.0.01', 88)

user_input = raw_input()

while user_input:
    mysocket.sendto(user_input, dest)     
    acknowledged = False
    # spam dest until they acknowledge me (sounds like my kids)
    while not acknowledged:
        try:
            ACK, address = mysocket.recvfrom(1024)
            acknowledged = True
        except socket.timeout:
            mysocket.sendto(user_input, dest)
    print ACK
    user_input = raw_input()

mysocket.close()
于 2013-04-09T19:15:11.333 回答