python uses epoll to implement server side methods

As shown below:

#!/usr/bin/python
# -*- coding: UTF-8 -*-
import socket
import select

send_data = "hello world!"
send_len = len(send_data)
recv_len = 1024
tcp_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
tcp_socket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
addr = ("0.0.0.0", 8765)
tcp_socket.bind(addr)
tcp_socket.listen(5)
tcp_socket.setblocking(False)
epoll = select.epoll()
'''( Edge trigger )select.EPOLLIN | select.EPOLLET'''
epoll.register(tcp_socket.fileno(), select.EPOLLIN)
''' because epoll The trigger event returned corresponds to the socket file descriptor, so you need to include the corresponding relationship in the dictionary '''
fd_to_socket = {tcp_socket.fileno():tcp_socket}

while True :
 events = epoll.poll(-1)
 for fd, event in events:
  fd_socket = fd_to_socket[fd]
  if fd == tcp_socket.fileno():
   while True:
    try:
     new_socket, new_addr = fd_socket.accept()
    except socket.error as e:
     (errno, err_msg) = e
     print errno
     print err_msg
     if errno == 11:
      break
    print "new accpet:", new_addr
    new_socket.setblocking(False)
    new_socket.setsockopt(socket.IPPROTO_TCP, socket.TCP_NODELAY, 1)
    epoll.register(new_socket.fileno(), select.EPOLLIN)
    fd_to_socket[new_socket.fileno()] = new_socket
  elif event&select.EPOLLIN:
   recv_datas = []
   recd = 0
   while (recd < recv_len):
    try:
     recv_data = fd_socket.recv(recv_len - recd)
     ''' Handle normal closure of reads '''
     if recv_data == "":
      print "close socket"
      epoll.unregister(fd)
      fd_to_socket[fd].close()
      del fd_to_socket[fd]
      break
     else:
      recv_datas.append(recv_data)
      recd = recd + len(recv_data)
    ''' Handle exception shutdown (EAGAIN,EINTR)'''
    except socket.error as e:
     (errno, err_msg) = e
     print errno
     print err_msg
     ''' Because it's triggered horizontally, EAGAIN Let's jump out of the loop and wait for the next trigger to read '''
     if errno == 11:
      break
     ''' Soft interrupt to continue reading '''
     elif errno == 4:
      continue
     ''' For other errors we simply close the socket '''
     else:
      print "close socket"
      epoll.unregister(fd)
      fd_to_socket[fd].close()
      del fd_to_socket[fd]
      break
    print repr(recv_datas)
    total_send = 0
    while total_send < send_len:
     sent = fd_socket.send(send_data[total_send:])
     if sent == 0:
      print "close socket"
      epoll.unregister(fd)
      fd_to_socket[fd].close()
      del fd_to_socket[fd]
      break
     else:
      print repr(send_data[total_send:])
      total_send = total_send + sent

We can also use exception handling here

except IOError as e:
  print e.errno
  print e.strerror