使用 select() 监听 tcp 和 udp 消息

问题描述

当我尝试此代码时，我只收到 TCP 消息:

I only get the TCP message when I try this code:

from socket import *
from select import select

def read_tcp(s):
    while True:
        client,addr = s.accept()
        data = client.recv(8000)
        client.close()
        print "Recv TCP:'%s'" % data

def read_udp(s):
    while True:
        data,addr = s.recvfrom(8000)
        print "Recv UDP:'%s'" % data

def run():
    host = ''
    port = 8888
    size = 8000
    backlog = 5

    # create tcp socket
    tcp = socket(AF_INET, SOCK_STREAM)
    tcp.bind(('',port))
    tcp.listen(backlog)

    # create udp socket
    udp = socket(AF_INET, SOCK_DGRAM)
    udp.bind(('',port))

    input = [tcp,udp]

    while True:
        inputready,outputready,exceptready = select(input,[],[])

        for s in inputready:
            if s == tcp:
                read_tcp(s)
            elif s == udp:
                read_udp(s)
            else:
                print "unknown socket:", s

if __name__ == '__main__':
    run()

而客户端是这样的:

from socket import *

def send_tcp():
    s = socket(AF_INET,SOCK_STREAM)
    s.connect(('localhost',8888))
    data="TCP "*4
    s.send(data)
    s.close()

def send_udp():
    s = socket(AF_INET,SOCK_DGRAM)
    data="UDP "*4
    s.sendto(data, ('localhost',8888))
    s.close()

if __name__ == '__main__':
    send_tcp()
    send_udp()

推荐答案

1. 摆脱 read_tcp() 和 read_udp() 中的while"循环.select() 循环是您唯一需要的循环:它将根据需要经常调用 read_XXX() 方法.read_XXX() 方法应该只处理一个事件.

1. Get rid of the 'while' loops in read_tcp() and read_udp(). The select() loop is the only loop you need: it will call the read_XXX() methods as often as required. The read_XXX() methods should handle exactly one event.

你的 read_tcp() 方法应该分成两部分:一个接受一个套接字并将其添加到选择集中，另一个读取一个接受的套接字.相应地调整选择循环.

Your read_tcp() method should be split into two parts: one to accept a socket and add it to the selection set, and another to read an accepted socket. Adjust the select loop accordingly.

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