提升requests模块的爬取效率

一、提升requests模块的爬取效率

　　1、多线程和多进程(不建议使用)

　　2、线程池或进程池(适当使用)

　　3、单线程+异步协程(爬虫推荐使用

二、爬取某视频到本地

import re
import time
import random
import requests
from lxml import etree

start_time = time.time()

url = "https://www.pearvideo.com/category_3"
headers = {
    "User-Agent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/79.0.3945.88 Safari/537.36"
}

ex = 'srcUrl="(.*?)",vdoUrl=srcUrl'

def request_video(url):
    """
    向视频链接发送请求
    """
    return requests.get(url=url, headers=headers).content

def save_video(content):
    """
    将视频的二进制数据保存到本地
    """
    video_name = str(random.randint(100, 999)) + ".mp4"
    with open(video_name, 'wb') as f:
        f.write(content)

        
# 获取首页源码
page_text = requests.get(url=url, headers=headers).text

tree = etree.HTML(page_text)
li_list = tree.xpath('//ul[@class="listvideo-list clearfix"]/li')

video_url_list = list()
for li in li_list:
    detail_url = "https://www.pearvideo.com/" + li.xpath('./div/a/@href')[0]
    
    # 获取该视频页面的源码
    detail_page_text = requests.get(url=detail_url, headers=headers).text
    
    # 正则匹配视频的URL
    video_url = re.findall(ex, detail_page_text, re.S)[0]
    video_url_list.append(video_url)
    
    content = request_video(video_url)
    save_video(content)


print("执行耗时: ", time.time() - start_time)