Python爬虫编程实践 Task04

爬取腾讯新闻

• 了解ajax加载
• 通过chrome的开发者工具，监控网络请求，并分析
• 用selenium完成爬虫
  • 具体流程如下：
  • 用selenium爬取https://news.qq.com/ 的热点精选

import time
from  selenium import webdriver
driver=webdriver.Chrome(executable_path="D:\chromedriver\chromedriver.exe")
driver.get("https://news.qq.com")
#了解ajax加载
for i in range(1,100):
    time.sleep(2)
    driver.execute_script("window.scrollTo(window.scrollX, %d);"%(i*200))

from bs4 import BeautifulSoup
html=driver.page_source
bsObj=BeautifulSoup(html,"lxml")
jxtits=bsObj.find_all("div",{
     "class":"jx-tit"})[0].find_next_sibling().find_all("li")

print("index",",","title",",","url")
for i,jxtit in enumerate(jxtits):
#     print(jxtit)
    
    try:
        text=jxtit.find_all("img")[0]["alt"]
    except:
        text=jxtit.find_all("div",{
     "class":"lazyload-placeholder"})[0].text
    try:
        url=jxtit.find_all("a")[0]["href"]
    except:
        print(jxtit)
    print(i+1,",",text,",",url) 

知乎爬虫

import requests
from http import cookiejar
Session=requests.session()
Session.cookies = cookiejar.LWPCookieJar(filename='./cookies.txt')
Session.cookies.load(ignore_discard=True)
Session.headers={
     
            'Host': 'www.zhihu.com',
            'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 '
                          '(KHTML, like Gecko) Chrome/66.0.3359.181 Safari/537.36'
        }
r=Session.get("https://www.zhihu.com/search?q=Datawhale&utm_content=search_history&type=content")
r.encoding="utf-8"

from bs4 import BeautifulSoup
import re
compiler=re.compile('"next":"(https:\\\\u002F\\\\u002Fapi.zhihu.com\\\\u002Fsearch_v3.*?)"')

bsObj=BeautifulSoup(r.text,"lxml")
url=compiler.findall(r.text)[0]

from urllib.parse import unquote
url=unquote(url,encoding="utf-8", errors='replace')
url=url.replace("\\u002F","/")
search_hash_id=re.search("search_hash_id=(.*?)&show_all_topics",url).group(1)

offset=20
lc_idx=21
for i in range(5):
    r=Session.get("https://www.zhihu.com/api/v4/search_v3?t=general&q=Datawhale&correction=1&offset={offset}&limit=20&lc_idx={lc_idx}&show_all_topics=0&search_hash_id={search_hash_id}&vertical_info=0%2C0%2C1%2C0%2C0%2C0%2C0%2C0%2C0%2C0".format(**{
     "offset":offset+i*20,"lc_idx":lc_idx+i*20,"search_hash_id":search_hash_id}))
    r.encoding="utf-8"
    print(r.json())
    print("\n"*20)