协程,线程,进程,多线程,多进程,线程池,本渣渣是彻底蒙蔽了,不过干就是了,二话不说写(抄)代码就是了,抄多了就明了了,说错了,写多了就会了!
Python通过yield提供了对协程的基本支持,但是不完全。而第三方的gevent为Python提供了比较完善的协程支持。
gevent是第三方库,通过greenlet实现协程,其基本思想是:
当一个greenlet遇到IO操作时,比如访问网络,就自动切换到其他的greenlet,等到IO操作完成,再在适当的时候切换回来继续执行。由于IO操作非常耗时,经常使程序处于等待状态,有了gevent为我们自动切换协程,就保证总有greenlet在运行,而不是等待IO。
greenlet是依次运行而不是交替运行。
要让greenlet交替运行,可以通过gevent.sleep()交出控制权
来源:廖雪峰博客
put与get方法是两个阻塞方法:put不到值程序夯住,get不到程序也夯住。
put_nowait与get_nowait方法是两个非阻塞方法:put_nowait没有值的话不等,get_nowait取不到值也不等了,程序不会夯住,但是一定要做异常处理!
#犀牛原厂
# -*- coding: utf-8 -*-
#20210827 微信:huguo00289
import requests
import random
from lxml import etree
from gevent import monkey
monkey.patch_socket()
import gevent
from gevent.queue import Queue
import time
import threading
import queue
from multiprocessing import Process
import multiprocessing
# 随机获取一个请求头
def get_user_agent():
user_agent = [
"Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10_6_8; en-us) AppleWebKit/534.50 (KHTML, like Gecko) Version/5.1 Safari/534.50",
"Mozilla/5.0 (Windows; U; Windows NT 6.1; en-us) AppleWebKit/534.50 (KHTML, like Gecko) Version/5.1 Safari/534.50",
"Mozilla/5.0 (Windows NT 10.0; WOW64; rv:38.0) Gecko/20100101 Firefox/38.0",
"Mozilla/5.0 (Windows NT 10.0; WOW64; Trident/7.0; .NET4.0C; .NET4.0E; .NET CLR 2.0.50727; .NET CLR 3.0.30729; .NET CLR 3.5.30729; InfoPath.3; rv:11.0) like Gecko",
"Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; Trident/5.0)",
"Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.0; Trident/4.0)",
"Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0)",
"Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1)",
"Mozilla/5.0 (Macintosh; Intel Mac OS X 10.6; rv:2.0.1) Gecko/20100101 Firefox/4.0.1",
"Mozilla/5.0 (Windows NT 6.1; rv:2.0.1) Gecko/20100101 Firefox/4.0.1",
"Opera/9.80 (Macintosh; Intel Mac OS X 10.6.8; U; en) Presto/2.8.131 Version/11.11",
"Opera/9.80 (Windows NT 6.1; U; en) Presto/2.8.131 Version/11.11",
"Mozilla/5.0 (Macintosh; Intel Mac OS X 10_7_0) AppleWebKit/535.11 (KHTML, like Gecko) Chrome/17.0.963.56 Safari/535.11",
"Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1; Maxthon 2.0)",
"Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1; TencentTraveler 4.0)",
"Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1)",
"Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1; The World)",
"Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1; Trident/4.0; SE 2.X MetaSr 1.0; SE 2.X MetaSr 1.0; .NET CLR 2.0.50727; SE 2.X MetaSr 1.0)",
"Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1; 360SE)",
"Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1; Avant Browser)",
"Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1)",
"Mozilla/5.0 (iPhone; U; CPU iPhone OS 4_3_3 like Mac OS X; en-us) AppleWebKit/533.17.9 (KHTML, like Gecko) Version/5.0.2 Mobile/8J2 Safari/6533.18.5",
"Mozilla/5.0 (iPod; U; CPU iPhone OS 4_3_3 like Mac OS X; en-us) AppleWebKit/533.17.9 (KHTML, like Gecko) Version/5.0.2 Mobile/8J2 Safari/6533.18.5",
"Mozilla/5.0 (iPad; U; CPU OS 4_3_3 like Mac OS X; en-us) AppleWebKit/533.17.9 (KHTML, like Gecko) Version/5.0.2 Mobile/8J2 Safari/6533.18.5",
"Mozilla/5.0 (Linux; U; Android 2.3.7; en-us; Nexus One Build/FRF91) AppleWebKit/533.1 (KHTML, like Gecko) Version/4.0 Mobile Safari/533.1",
"MQQBrowser/26 Mozilla/5.0 (Linux; U; Android 2.3.7; zh-cn; MB200 Build/GRJ22; CyanogenMod-7) AppleWebKit/533.1 (KHTML, like Gecko) Version/4.0 Mobile Safari/533.1",
"Opera/9.80 (Android 2.3.4; Linux; Opera Mobi/build-1107180945; U; en-GB) Presto/2.8.149 Version/11.10",
"Mozilla/5.0 (Linux; U; Android 3.0; en-us; Xoom Build/HRI39) AppleWebKit/534.13 (KHTML, like Gecko) Version/4.0 Safari/534.13",
"Mozilla/5.0 (BlackBerry; U; BlackBerry 9800; en) AppleWebKit/534.1+ (KHTML, like Gecko) Version/6.0.0.337 Mobile Safari/534.1+",
"Mozilla/5.0 (hp-tablet; Linux; hpwOS/3.0.0; U; en-US) AppleWebKit/534.6 (KHTML, like Gecko) wOSBrowser/233.70 Safari/534.6 TouchPad/1.0",
"Mozilla/5.0 (SymbianOS/9.4; Series60/5.0 NokiaN97-1/20.0.019; Profile/MIDP-2.1 Configuration/CLDC-1.1) AppleWebKit/525 (KHTML, like Gecko) BrowserNG/7.1.18124",
"Mozilla/5.0 (compatible; MSIE 9.0; Windows Phone OS 7.5; Trident/5.0; IEMobile/9.0; HTC; Titan)",
"UCWEB7.0.2.37/28/999",
"NOKIA5700/ UCWEB7.0.2.37/28/999",
"Openwave/ UCWEB7.0.2.37/28/999",
"Mozilla/4.0 (compatible; MSIE 6.0; ) Opera/UCWEB7.0.2.37/28/999",
# iPhone 6:
"Mozilla/6.0 (iPhone; CPU iPhone OS 8_0 like Mac OS X) AppleWebKit/536.26 (KHTML, like Gecko) Version/8.0 Mobile/10A5376e Safari/8536.25",
]
headers = {'User-Agent': random.choice(user_agent)}
return headers
def get_urllist(url):
html=requests.get(url=url,headers=get_user_agent(),timeout=6).content.decode('utf-8')
tree=etree.HTML(html)
hrefs=tree.xpath('//div[@class="deanpiclicr"]/h2/a/@href')
# print(len(hrefs))
print(hrefs)
urls_work = Queue()
for i in range(1, 28):
url = "https://www.rhino3d.asia/portal.php?mod=list&catid=1&page=%d" % i
urls_work.put_nowait(url)
def get_url_pool():
while not urls_work.empty():
url = urls_work.get_nowait()
get_urllist(url)
def ge():
startTime=time.time()
tasks_list = []
for x in range(5):
task = gevent.spawn(get_url_pool)
tasks_list.append(task)
gevent.joinall(tasks_list)
endTime = time.time()
print('gevent用时:',endTime-startTime)
def pe():
startTime = time.time()
for i in range(1, 28):
url = "https://www.rhino3d.asia/portal.php?mod=list&catid=1&page=%d" % i
get_urllist(url)
endTime = time.time()
print('单线程用时:', endTime - startTime)
# 创建队列
q = queue.Queue()
for i in range(1, 28):
url = "https://www.rhino3d.asia/portal.php?mod=list&catid=1&page=%d" % i
q.put(url)
def th_pool():
while not q.empty():
url = q.get()
get_urllist(url)
def run():
startTime = time.time()
threads = []
for x in range(5):
t = threading.Thread(target=th_pool)
threads.append(t)
for i in threads:
i.start()
for i in threads:
i.join()
endTime = time.time()
print('多线程用时:', endTime - startTime)
def prun():
startTime = time.time()
pros = []
for x in range(5):
t = Process(target=th_pool)
pros.append(t)
for i in pros:
i.start()
for i in pros:
i.join()
endTime = time.time()
print('多进程用时:', endTime - startTime)
def pprun():
startTime = time.time()
pool = multiprocessing.Pool(processes=4) #进程池设置了4个进行
for i in range(1, 28):
url = "https://www.rhino3d.asia/portal.php?mod=list&catid=1&page=%d" % i
pool.apply_async(func=get_urllist, args=(url,))
pool.close()
pool.join()
endTime = time.time()
print('多进程用时:', endTime - startTime)
if __name__=='__main__':
pe() #单线程
ge() #协程
run() #多线程
#prun() #未成功多进程
pprun() #线程池多进程
耗时参考
来源:
https://www.liaoxuefeng.com/wiki/897692888725344/966405998508320
https://www.cnblogs.com/paulwhw/articles/10723887.html
·················END·················
本文分享自 Python与SEO学习 微信公众号,前往查看
如有侵权,请联系 cloudcommunity@tencent.com 删除。
本文参与 腾讯云自媒体同步曝光计划 ,欢迎热爱写作的你一起参与!