Python中IO多路复用socket

使用epoll+socket来玩IO多路复用

前言

虽然非阻塞socket能够实现单process同时处理多个网络IO事件(client), 但是socket的setblocking是用不断轮询的方式来达到非阻塞处理client的, 所有难免会浪费CPU资源.

然而, epoll(epoll 为linux中效率最高的 IO多路复用), 计算机底层的机制, 可以来检测send, recv等即检测socket是否发生变化(是否出现读写事件), 避免了socket轮询监听浪费资源.

eg: 如果有客户端连接那么server会变为可读事件(也就是socket有数据了可以进行读操作).

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使用

server

import socket
import selectors    # IO多路复用的选择器. 优于select.


def server_accept(sock):
    connected, addr = server.accept()
    sel.register(connected, selectors.EVENT_READ, server_recv)

def server_recv(connected):
    data = connected.recv(1024)
    if data:
        print(data.decode('utf-8'))
        connected.send(b"I'm received. info: %s" % data)
    else:
        print("It's over.")
        sel.unregister(connected)   # 注销socket.
        connected.close()

sel = selectors.DefaultSelector()   # 选择对应操作系统的技术, win为select linux为epoll.
server = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
server.bind((socket.gethostbyname(socket.gethostname()), 4444))
server.listen(5)
sel.register(server, selectors.EVENT_READ, server_accept)  # args: socket event callback
print("start listen....")

while True:
    try:
        events = sel.select()
        for key, mask in events:
        # 取events中的key元素中的data(为callback), 并传入socket. return is none.
            key.data(key.fileobj)   

    except (BlockingIOError, ConnectionResetError):
        pass

client

# client
import socket
import time

client = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
client.connect((socket.gethostbyname(socket.gethostname()), 4444))

while True:
    cRequest = input("send: ")
    client.send(cRequest.encode())
    cResponse = client.recv(1024)
    print(cResponse)
    if cRequest == "quit":
        print("[+] Down line......")
        time.sleep(2)
        client.close()
        break

大致思路

1.create socket_obj
2.bind
3.listen
4.sel.register
5.sel.select
while True

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