ok,首先写一个python socket的server段,对开放三个端口:10000,10001,10002.krondo的例子中是每个server绑定一个端口,测试的时候需要分别开3个shell,分别运行.这太麻烦了,就分别用三个thread来运行这些services.

import optparse

import os

import socket

import time

from threading import thread

import stringio

txt = '''1111

2222

3333

4444

'''

def server(listen_socket):

while true:

buf = stringio.stringio(txt)

sock, addr = listen_socket.accept()

print 'somebody at %s wants poetry!' % (addr,)

while true:

try:

line = buf.readline().strip()

if not line:

sock.close()

break

sock.sendall(line) # this is a blocking call

print 'send bytes to client:%s' % line

#sock.close()

except socket.error:

sock.close()

break

time.sleep(1) #server和client连接后，server会故意每发送一个单词后等待一秒钟后再发送另一个单词

def main():

ports = [10000, 10001, 10002]

for port in ports:

listen_socket = socket.socket(socket.af_inet, socket.sock_stream)

listen_socket.setsockopt(socket.sol_socket, socket.so_reuseaddr, 1)

addres = (str('127.0.0.1'), port)

listen_socket.bind(addres)

listen_socket.listen(5)

print "start listen at:%s" % (port,)

worker = thread(target = server, args = [listen_socket])

worker.setdaemon(true)

worker.start()

if __name__ == '__main__':

main()

while true:

time.sleep(0.1) #如果不sleep的话,cpu会被python完全占用了

pass

下面是一个client,没有才用异步网络,连接这个三个端口的server:

import socket

if __name__ == '__main__':

ports = [10000, 10001, 10002]

for port in ports:

address = (str('127.0.0.1'), port)

sock = socket.socket(socket.af_inet, socket.sock_stream)

sock.connect(address)

poem = ''

while true:

data = sock.recv(4)

if not data:

sock.close()

break

poem += data

print poem

下面用异步的client来读取，代码如下：

import datetime, errno, optparse, select, socket

def connect(port):

"""connect to the given server and return a non-blocking socket."""

address = (str('127.0.0.1'), port)

sock = socket.socket(socket.af_inet, socket.sock_stream)

sock.connect(address)

sock.setblocking(0)

return sock

def format_address(address):

host, port = address

return '%s:%s' % (host or '127.0.0.1', port)

if __name__ == '__main__':

ports = [10000, 10001, 10002]

start = datetime.datetime.now()

sockets = map(connect, ports)

poems = dict.fromkeys(sockets, '') # socket -> accumulated poem

# socket -> task numbers

sock2task = dict([(s, i + 1) for i, s in enumerate(sockets)])

sockets = list(sockets) # make a copy

while sockets:

#运用select来确保那些可读取的异步socket可以立即开始读取io

#os不停的搜索目前可以read的socket，有的话就返回rlist

rlist, _, _ = select.select(sockets, [], [])

for sock in rlist:

data = ''

while true:

try:

new_data = sock.recv(1024)

except socket.error, e:

if e.args[0] == errno.ewouldblock:

break

raise

else:

if not new_data:

break

else:

print new_data

data += new_data

task_num = sock2task[sock]

if not data:

sockets.remove(sock)

sock.close()

print 'task %d finished' % task_num

else:

addr_fmt = format_address(sock.getpeername())

msg = 'task %d: got %d bytes of poetry from %s'

print msg % (task_num, len(data), addr_fmt)

poems[sock] += data

elapsed = datetime.datetime.now() - start

print 'got poems in %s' % elapsed

结果只需要4秒就完成了读取任务。效率是刚才同步socket的三倍。对客户端的异步改造主要有两点：

同步模式下，客户端分别创建socket；而在异步模式下，client开始就创建了所有的socket。

通过“sock.setblocking(0)”设置socket为异步模式。

通过unix系统的select俩返回可读取io

最为核心的是26行和29行。尤其是29行的select操作返回待读取socket的列表。

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