how to use linux epoll with python

 
     
     #!/usr/bin/python
 
     
     # -*- coding:utf-8 -*-

 
     
     import socket, select

 
     
     EOL1 = b'\n\n'
 
     
     EOL2 = b'\n\r\n'
 
     
     response  = b'HTTP/1.0 200 OK\r\nDate: Mon, 1 Jan 1996 01:01:01 GMT\r\n'
 
     
     response += b'Content-Type: text/plain\r\nContent-Length: 13\r\n\r\n'
 
     
     response += b'Hello, world!'

 
     
     serversocket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
 
     
     serversocket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
 
     
     serversocket.bind(('0.0.0.0', 8080))
 
     
     serversocket.listen(1)
 
     
     serversocket.setblocking(0)

 
     
     epoll = select.epoll()
 
     
     epoll.register(serversocket.fileno(), select.EPOLLIN)

 
     
     try:
 
     
       connections = {}; requests = {}; responses = {}

 
     
       while True:
 
     
          events = epoll.poll(1)

 
     
          for fileno, event in events:
 
     
             if fileno == serversocket.fileno():
 
     
                connection, address = serversocket.accept()
 
     
                connection.setblocking(0)
 
     
                epoll.register(connection.fileno(), select.EPOLLIN)

 
     
                connections[connection.fileno()] = connection
 
     
                requests[connection.fileno()] = b''
 
     
                responses[connection.fileno()] = response

 
     
             elif event & select.EPOLLIN:
 
     
                requests[fileno] += connections[fileno].recv(1024)

 
     
                if EOL1 in requests[fileno] or EOL2 in requests[fileno]:
 
     
                   epoll.modify(fileno, select.EPOLLOUT)
 
     
                   print('-'*40 + '\n' + requests[fileno].decode()[:-2])

 
     
             elif event & select.EPOLLOUT:
 
     
                byteswritten = connections[fileno].send(responses[fileno])
 
     
                responses[fileno] = responses[fileno][byteswritten:]

 
     
                if len(responses[fileno]) == 0:
 
     
                   epoll.modify(fileno, 0)
 
     
                   connections[fileno].shutdown(socket.SHUT_RDWR)

 
     
             elif event & select.EPOLLHUP:
 
     
                epoll.unregister(fileno)
 
     
                connections[fileno].close()
 
     
                del connections[fileno]

 
     
     finally:
 
     
       epoll.unregister(serversocket.fileno())
 
     
       epoll.close()
 
     
       serversocket.close()

转载自： http://scotdoyle.com/python-epoll-howto.html.  python epoll编程基本上都是从这篇文章开始。

 

epoll流程：

创建socket

  -->绑定socket并监听

      -->创建epoll对象

          -->注册socket到epoll对象，使用epoll的注册函数对socket进行管理

              -->服务器进入循环

                -->epoll对象轮询注册的socket队列（即：已经就绪的socket队列）

                  -->判断socket是否是新加入的

                     ->新加入socket：创建socket对象，并调用accept()，然后把socket注册到epoll

                     ->非新socket，且socket状态为可读，调用recv()。如果接收到的消息包含中断或exit等字符，修改socket状态

                     ->非新socket，且状态为可写，调用send函数。

                     ->非新socket，且状态为HUP，从注册函数中删除socket，并调用close()