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提升requests模块爬取数据的效率
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import requests
import time
headers = {
'User-Agent':'Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/70.0.3538.77 Safari/537.36'
}
同步代码
flask服务器代码：
from flask import Flask
from time import sleep
app = Flask(name)
​
@app.route('/bobo')
def index1():
sleep(2)
return 'hello bobo!'
@app.route('/jay')
def index2():
sleep(2)
return 'hello jay!'
@app.route('/tom')
def index3():
sleep(2)
return 'hello tom!'
app.run()
​
start = time.time()
urls = [
'http://127.0.0.1:5000/bobo',
'http://127.0.0.1:5000/jay',
'http://127.0.0.1:5000/tom',
]
for url in urls:
page_text = requests.get(url,headers=headers).text
print(page_text)

print(time.time()-start)

hello bobo!
hello jay!
hello tom!
6.016878366470337
基于线程池实现异步爬取
from multiprocessing.dummy import Pool #线程池模块

必须只可以有一个参数

def my_requests(url):
return requests.get(url=url,headers=headers).text
​
​
start = time.time()
urls = [
'http://127.0.0.1:5000/bobo',
'http://127.0.0.1:5000/jay',
'http://127.0.0.1:5000/tom',
]
​
pool = Pool(3)

map：两个参数

参数1：自定义的函数，必须只可以有一个参数

参数2：列表or字典

map的作用就是让参数1表示的自定义的函数异步处理参数2对应的列表或者字典中的元素

page_texes = pool.map(my_requests,urls)
print(page_texes)
​
​
print(time.time()-start)
['hello bobo!', 'hello jay!', 'hello tom!']
2.0126171112060547
asyncio
如何产生一个携程对象
什么是任务对象
任务对象和携程对象的区别
任务对象如何绑定一个回调呢
什么是事件循环呢？
aiohttp
​