OK,首先寫一個python socket的server段,對開放三個端口:10000,10001,10002.krondo的例子中是每個server綁定一個端口,測試的時候需要分別開3個shell,分別運(yùn)行.這太麻煩了,就分別用三個Thread來運(yùn)行這些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連接后，server會故意每發(fā)送一個單詞后等待一秒鐘后再發(fā)送另一個單詞
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的話,CPU會被Python完全占用了
pass
下面是一個client,沒有才用異步網(wǎng)絡(luò),連接這個三個端口的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
下面用異步的client來讀取，代碼如下：
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:
#運(yùn)用select來確保那些可讀取的異步socket可以立即開始讀取IO
#OS不停的搜索目前可以read的socket，有的話就返回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
結(jié)果只需要4秒就完成了讀取任務(wù)。效率是剛才同步socket的三倍。對客戶端的異步改造主要有兩點(diǎn)：
同步模式下，客戶端分別創(chuàng)建socket；而在異步模式下，client開始就創(chuàng)建了所有的socket。
通過“sock.setblocking(0)”設(shè)置socket為異步模式。
通過Unix系統(tǒng)的select倆返回可讀取IO
最為核心的是26行和29行。尤其是29行的select操作返回待讀取socket的列表。
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