Question

嗨，我关注并理解了这篇关于如何从网站读取内容的文章，该文章非常有效： geeksforgeeks.org:Reading selected webpage content using Python Web Scraping

但是当我更改代码以与另一个站点一起使用时，它不返回任何值。我正在尝试获取那些Value1和Value2等。如下所示。

请注意：从该网页读取内容是合法的。

import requests 
from bs4 import BeautifulSoup 

# the target we want to open     
url='https://hackerone.com/directory?offers_bounties=true&asset_type=URL&order_direction=DESC&order_field=started_accepting_at'

#open with GET method 
resp=requests.get(url) 

#http_respone 200 means OK status 
if resp.status_code==200: 
    print("Successfully opened the web page") 
    print("The news are as follow :-\n") 

    # we need a parser,Python built-in HTML parser is enough . 
    soup=BeautifulSoup(resp.text,'html.parser')     

    # l is the list which contains all the text i.e news  
    l=soup.find("tr","spec-directory-entry daisy-table__row fade fade--show") 

    #now we want to print only the text part of the anchor. 
    #find all the elements of a, i.e anchor 
    for i in l: 
        print(i.text) 
else: 
    print("Error")

这是网站源代码：

<tr class="spec-directory-entry daisy-table__row fade fade--show">
    <a href="/livestream" class="daisy-link spec-profile-name">Value1</a>
<tr class="spec-directory-entry daisy-table__row fade fade--show">
    <a href="/livestream" class="daisy-link spec-profile-name">Value2</a>
<tr class="spec-directory-entry daisy-table__row fade fade--show">
.
.
.

Answer 1

需要JavaScript来呈现网页内容。使用prerenderio服务是一种从页面中获取所需数据的简便方法。

import requests 
from bs4 import BeautifulSoup 

# the target we want to open
# changed to use prerenderio service 
url='http://service.prerender.io/https://hackerone.com/directory?offers_bounties=true&asset_type=URL&order_direction=DESC&order_field=started_accepting_at'

#open with GET method 
resp=requests.get(url) 

#http_respone 200 means OK status 
if resp.status_code==200: 
    print("Successfully opened the web page") 
    print("The news are as follow :-\n") 

    # we need a parser,Python built-in HTML parser is enough . 
    soup=BeautifulSoup(resp.text,'html.parser')     

    # l is the list which contains all the text i.e news  
    l=soup.find("tr","spec-directory-entry daisy-table__row fade fade--show") 

    #now we want to print only the text part of the anchor. 
    #find all the elements of a, i.e anchor 
    for i in l: 
        print(i.text) 
else: 
    print("Error")

以上代码返回的数据：

Successfully opened the web page
The news are as follow :-

LivestreamManaged
04 / 2019
73
$100
$150-$250

已编辑：回复Ahmad's comment

这里是仅获取“ Livestream”表行的值的代码。

import requests 
from bs4 import BeautifulSoup 

# the target we want to open
# changed to use prerenderio service 
url='http://service.prerender.io/https://hackerone.com/directory?offers_bounties=true&asset_type=URL&order_direction=DESC&order_field=started_accepting_at'

#open with GET method 
resp=requests.get(url) 

#http_respone 200 means OK status 
if resp.status_code==200: 
    print("Successfully opened the web page") 
    print("The news are as follow :-\n") 

    # we need a parser,Python built-in HTML parser is enough . 
    soup=BeautifulSoup(resp.text,'html.parser')     

    # l is the list which contains all "tr" tags  
    l=soup.findAll("tr","spec-directory-entry daisy-table__row fade fade--show")

    # looping through the list of table rows
    for i in l:
        # checking if the current row is for 'Livestream'
        if i.find('a').text == 'Livestream':
          # printing the row's values except the first "td" tag
          for e in i.findAll('td')[1:]:
            print(e.text)
else: 
    print("Error")

结果：

Successfully opened the web page
The news are as follow :-

04 / 2019
73
$100
$150-$250

Answer 2

看起来像JS渲染到页面上。您可以同时使用硒和美丽汤来获取价值。

from selenium import webdriver
import time
from bs4 import BeautifulSoup

driver=webdriver.Chrome()
driver.get("https://hackerone.com/directory?offers_bounties=true&asset_type=URL&order_direction=DESC&order_field=started_accepting_at")
time.sleep(5)
html=driver.page_source
soup=BeautifulSoup(html,'html.parser')
for a in soup.select("a.spec-profile-name[href='\/livestream']"):
    print(a.text)

Answer 3

查看请求实际获取的内容，看来此页面依赖于动态内容。您的请求中返回以下文本：

It looks like your JavaScript is disabled. To use HackerOne, enable JavaScript in your browser and refresh this page.

您会收到“ TypeError：'NoneType'对象不可迭代”的信息，因为没有Javascript，BeautifulSoup就找不到并进行迭代的“ tr”元素。您将不得不使用诸如selenium之类的东西来模拟运行Javascript的浏览器，以获取所需的HTML。

beautifulsoup4不返回内容

3 个答案: