python 网络编程之socket udp

2019独角兽企业重金招聘Python工程师标准>>>

 

一、环境

    windows10 + python3.6

二、code

#!/usr/bin/env python3
# coding=utf-8

import argparse, random, socket, sys

MAX_BYTES = 65535


def server(interface, port):
    sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
    sock.bind((interface, port))
    print('Listening at', sock.getsockname())
    while True:
        data, address = sock.recvfrom(MAX_BYTES)
        if random.random() < 0.5:
            print('Pretending to drop packet from {}'.format(address))
            continue
        text = data.decode('ascii')
        print('The client at {} says {!r}'.format(address, text))
        message = 'You data was {} bytes long'.format(len(data))
        sock.sendto(message.encode('ascii'), address)


def client(hostname, port):
    sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
    hostname = sys.argv[2]
    sock.connect((hostname, port))
    print('Client socket name is {}'.format(sock.getsockname()))

    delay = 0.1  # seconds
    text = 'This is another message'
    data = text.encode('ascii')
    while True:
        sock.send(data)
        print('Waiting up to {} seconds for a reply'.format(delay))
        sock.settimeout(delay)
        try:
            data = sock.recv(MAX_BYTES)     # recv() is block
        except socket.timeout:
            '''exponential backoff(指数退避)'''
            delay *= 2  # wait even longer for the next request
            if delay > 2.0:
                raise RuntimeError('I think the server is down')
        else:
            break   # we are done, and can stop looping
    print('The server says {!r}'.format(data.decode('ascii')))

if __name__ == '__main__':
    choices = {'client': client, 'server': server}
    parser = argparse.ArgumentParser(description='Send and receive UDP,'
                                     'pretending packets are often dropped')
    parser.add_argument('role', choices=choices, help='Which role to take')
    parser.add_argument('host', help='interface the server listens at;'
                        'host the client sends to')
    parser.add_argument('-p', metavar='PORT', type=int, default=1060,
                        help="UDP port (default 1060)")
    args = parser.parse_args()
    function = choices[args.role]
    function(args.host, args.p)

 

udp广播

#!/usr/bin/env python3
# coding=utf-8

import argparse, socket

BUFSIZE = 65535


def server(interface, port):
    sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
    sock.bind((interface, port))
    print('Listening for datagrams at {}'.format(sock.getsockname()))
    while True:
        data, address = sock.recvfrom(BUFSIZE)
        text = data.decode('ascii')
        print('The client at {} says: {!r}'.format(address, text))


def client(network, port):
    sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
    sock.setsockopt(socket.SOL_SOCKET, socket.SO_BROADCAST, 1)
    text = 'Broadcast datagram!'
    sock.sendto(text.encode('ascii'), (network, port))


if __name__ == '__main__':
    choices = {'client': client, 'server': server}
    parser = argparse.ArgumentParser(description='Send,receive UDP broadcast')
    parser.add_argument('role', choices=choices, help='wich role to take')
    parser.add_argument('host', help='interface the server listens at;'
                                     'network the client sends to')
    parser.add_argument('-p', metavar='port', type=int, default=1060,
                        help='UDP port (default 1060)')
    args = parser.parse_args()
    function = choices[args.role]
    function(args.host, args.p)

 

转载于:https://my.oschina.net/medivhxu/blog/1581560