转一贴，今天实在写累了，也看累了--【Python异步非阻塞IO多路复用Select/Poll/Epoll使用】

下面这篇，原理理解了，

再结合 这一周来的心得体会，整个框架就差不多了。。。

http://www.haiyun.me/archives/1056.html

有许多封装好的异步非阻塞IO多路复用框架，底层在linux基于最新的epoll实现，为了更好的使用，了解其底层原理还是有必要的。
下面记录下分别基于Select/Poll/Epoll的echo server实现。
Python Select Server，可监控事件数量有限制：

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#!/usr/bin/python # -*- coding: utf-8 -*- import select import socket import Queue    server = socket.socket(socket.AF_INET,socket.SOCK_STREAM) server.setblocking(False) server.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR  , 1) server_address= ('192.168.1.5',8080) server.bind(server_address) server.listen(10)    #select轮询等待读socket集合 inputs = [server] #select轮询等待写socket集合 outputs = [] message_queues = {} #select超时时间 timeout = 20    while True:     print "等待活动连接......"     readable , writable , exceptional = select.select(inputs, outputs, inputs, timeout)        if not (readable or writable or exceptional) :         print "select超时无活动连接，重新select...... "         continue;       #循环可读事件     for s in readable :         #如果是server监听的socket         if s is server:             #同意连接             connection, client_address = s.accept()             print "新连接： ", client_address             connection.setblocking(0)             #将连接加入到select可读事件队列             inputs.append(connection)             #新建连接为key的字典，写回读取到的消息             message_queues[connection] = Queue.Queue()         else:             #不是本机监听就是客户端发来的消息             data = s.recv(1024)             if data :                 print "收到数据：" , data , "客户端：",s.getpeername()                 message_queues[s].put(data)                 if s not in outputs:                     #将读取到的socket加入到可写事件队列                     outputs.append(s)             else:                 #空白消息，关闭连接                 print "关闭连接：", client_address                 if s in outputs :                     outputs.remove(s)                 inputs.remove(s)                 s.close()                 del message_queues[s]     for s in writable:         try:             msg = message_queues[s].get_nowait()         except Queue.Empty:             print "连接：" , s.getpeername() , '消息队列为空'             outputs.remove(s)         else:             print "发送数据：" , msg , "到", s.getpeername()             s.send(msg)            for s in exceptional:         print "异常连接：", s.getpeername()         inputs.remove(s)         if s in outputs:             outputs.remove(s)         s.close()         del message_queues[s]

Python Poll Server，Select升级版，无可监控事件数量限制，还是要轮询所有事件：

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#!/usr/bin/python # -*- coding: utf-8 -*- import socket import select import Queue    server = socket.socket(socket.AF_INET, socket.SOCK_STREAM) server.setblocking(False) server.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1) server_address = ("192.168.1.5", 8080) server.bind(server_address) server.listen(5) print  "服务器启动成功，监听IP：" , server_address message_queues = {} #超时，毫秒 timeout = 5000 #监听哪些事件 READ_ONLY = ( select.POLLIN | select.POLLPRI | select.POLLHUP | select.POLLERR) READ_WRITE = (READ_ONLY|select.POLLOUT) #新建轮询事件对象 poller = select.poll() #注册本机监听socket到等待可读事件事件集合 poller.register(server,READ_ONLY) #文件描述符到socket映射 fd_to_socket = {server.fileno():server,} while True:     print "等待活动连接......"     #轮询注册的事件集合     events = poller.poll(timeout)     if not events:       print "poll超时，无活动连接，重新poll......"       continue     print "有" , len(events), "个新事件，开始处理......"     for fd ,flag in events:         s = fd_to_socket[fd]         #可读事件         if flag & (select.POLLIN | select.POLLPRI) :             if s is server :                 #如果socket是监听的server代表有新连接                 connection , client_address = s.accept()                 print "新连接：" , client_address                 connection.setblocking(False)                                    fd_to_socket[connection.fileno()] = connection                 #加入到等待读事件集合                 poller.register(connection,READ_ONLY)                 message_queues[connection]  = Queue.Queue()             else :                 #接收客户端发送的数据                 data = s.recv(1024)                 if data:                     print "收到数据：" , data , "客户端：" , s.getpeername()                     message_queues[s].put(data)                     #修改读取到消息的连接到等待写事件集合                     poller.modify(s,READ_WRITE)                 else :                     # Close the connection                     print "  closing" , s.getpeername()                     # Stop listening for input on the connection                     poller.unregister(s)                     s.close()                     del message_queues[s]         #连接关闭事件         elif flag & select.POLLHUP :             print " Closing ", s.getpeername() ,"(HUP)"             poller.unregister(s)             s.close()         #可写事件         elif flag & select.POLLOUT :             try:                 msg = message_queues[s].get_nowait()             except Queue.Empty:                 print s.getpeername() , " queue empty"                 poller.modify(s,READ_ONLY)             else :                 print "发送数据：" , data , "客户端：" , s.getpeername()                 s.send(msg)         #异常事件         elif flag & select.POLLERR:             print "  exception on" , s.getpeername()             poller.unregister(s)             s.close()             del message_queues[s]

Python Epoll Server，基于回调的事件通知模式，轻松管理大量连接：

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#!/usr/bin/python # -*- coding: utf-8 -*- import socket, select import Queue   serversocket = socket.socket(socket.AF_INET, socket.SOCK_STREAM) serversocket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1) server_address = ("192.168.1.5", 8080) serversocket.bind(server_address) serversocket.listen(1) print  "服务器启动成功，监听IP：" , server_address serversocket.setblocking(0) timeout = 10 #新建epoll事件对象，后续要监控的事件添加到其中 epoll = select.epoll() #添加服务器监听fd到等待读事件集合 epoll.register(serversocket.fileno(), select.EPOLLIN) message_queues = {}   fd_to_socket = {serversocket.fileno():serversocket,} while True:   print "等待活动连接......"   #轮询注册的事件集合   events = epoll.poll(timeout)   if not events:      print "epoll超时无活动连接，重新轮询......"      continue   print "有" , len(events), "个新事件，开始处理......"   for fd, event in events:      socket = fd_to_socket[fd]      #可读事件      if event & select.EPOLLIN:          #如果活动socket为服务器所监听，有新连接          if socket == serversocket:             connection, address = serversocket.accept()             print "新连接：" , address             connection.setblocking(0)             #注册新连接fd到待读事件集合             epoll.register(connection.fileno(), select.EPOLLIN)             fd_to_socket[connection.fileno()] = connection             message_queues[connection]  = Queue.Queue()          #否则为客户端发送的数据          else:             data = socket.recv(1024)             if data:                print "收到数据：" , data , "客户端：" , socket.getpeername()                message_queues[socket].put(data)                #修改读取到消息的连接到等待写事件集合                epoll.modify(fd, select.EPOLLOUT)      #可写事件      elif event & select.EPOLLOUT:         try:            msg = message_queues[socket].get_nowait()         except Queue.Empty:            print socket.getpeername() , " queue empty"            epoll.modify(fd, select.EPOLLIN)         else :            print "发送数据：" , data , "客户端：" , socket.getpeername()            socket.send(msg)      #关闭事件      elif event & select.EPOLLHUP:         epoll.unregister(fd)         fd_to_socket[fd].close()         del fd_to_socket[fd] epoll.unregister(serversocket.fileno()) epoll.close() serversocket.close()