协程demo，1异步爬网页 2异步socket请求

Posted 2021-01-08 staff

一、异步爬网页

‘‘‘
协程并发爬网页
‘‘‘
from urllib import request
import gevent,time
from gevent import monkey  # 让gevent知道urllib里的哪些操作属于IO操作

monkey.patch_all()   # 标记当前程序所有的IO操作

def f(url):
    print("GET:{0}".format(url))
    resp = request.urlopen(url)
    data = resp.read()
    print(‘{0} bytes received from {1}‘.format(len(data), url))

time_start = time.time()
f("https://www.python.org")
f("https://www.yahoo.com")
f("https://github.com")
print("同步耗时：{0}".format(time.time()-time_start))

async_time_start = time.time()
gevent.joinall([gevent.spawn(f,"https://www.python.org"),
                gevent.spawn(f, "https://www.yahoo.com"),
                gevent.spawn(f, "https://github.com")])
print("异步耗时：{0}".format(time.time()-async_time_start))

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GET:https://www.python.org
49060 bytes received from https://www.python.org
GET:https://www.yahoo.com
498196 bytes received from https://www.yahoo.com
GET:https://github.com
64978 bytes received from https://github.com
同步耗时：10.61960744857788
GET:https://www.python.org
GET:https://www.yahoo.com
GET:https://github.com
86167 bytes received from https://github.com
49060 bytes received from https://www.python.org
503102 bytes received from https://www.yahoo.com
异步耗时：3.7582149505615234
‘‘‘

二、异步处理socket请求

服务端：

import socket
import gevent
from gevent import monkey

monkey.patch_all()

def server(port):
    s = socket.socket()
    s.bind((‘0.0.0.0‘, port))
    s.listen(500)
    while True:
        cli, addr = s.accept()  # 之前多并发是启动一个线程
        gevent.spawn(handle_request, cli)

def handle_request(conn):
    try:
        while True:
            data = conn.recv(1024)
            print("recv:", data)
            conn.send(data)
            if not data:
                conn.shutdown(socket.SHUT_WR)
    except Exception as ex:
        print(ex)
    finally:
        conn.close()

if __name__ == ‘__main__‘:
    server(8001)

客户端：

import socket

HOST = ‘localhost‘
PORT = 8001

s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect((HOST, PORT))
while True:
    msg = bytes(input(">>").strip(), encoding="utf-8")
    s.sendall(msg)
    data = s.recv(1024)
    print("Received:", repr(data))
s.close()