BeautifulSoup img src获取base64而不是实际链接

Question

我不熟悉使用bs4进行网页抓取，我想从蛋白质数据库（PDB）获取蛋白质图像：

https://www.rcsb.org/structure/1A69

当我用Chrome Inspector检查HTML时，我看到图像是通过一个http链接获得的，我可以很容易地找到并保存图像

<img class="img-responsive center-block mainImage" 
     src="https://cdn.rcsb.org/images/rutgers/a6/1a69/1a69.pdb1-500.jpg">

然而，当我运行脚本提取src时，我只得到base64

data:image/gif;base64,R0lGODlhAQABAAD/ACwAAAAAAQABAAACADs=

我做错什么了吗？发生了什么事？有没有办法从base64获取http链接

我的代码：

from bs4 import BeautifulSoup as bs
from urllib.request import urlopen

url = "https://www.rcsb.org/structure/1A69"
resp = urlopen(url)
page = bs(resp,"html.parser")

for img in page.findAll('img',{'class':'img-responsive'}):
    src = img['src']
    print(src)

Answer 1

图像URL由Javascript动态组合，但您可以使用以下Python脚本模拟组合：

import requests
from bs4 import BeautifulSoup

url = 'https://www.rcsb.org/structure/1A69'
soup = BeautifulSoup(requests.get(url).content, 'html.parser')
pdb_id = url.split('/')[-1].lower()
images_location = "https://cdn.rcsb.org/images/rutgers/"
num_items = len( soup.select('#carousel-structuregallery .item') )
pdb_hash = pdb_id[1:3]

# print image urls to screen:

for i in range(num_items):
    # 0 = Asymmetric; 1+ = Biological Assembly
    if i == 0:
        img_url = images_location + pdb_hash + '/' + pdb_id + '/' + pdb_id + '.pdb-500.jpg'
    else:
        img_url = images_location + pdb_hash + '/' + pdb_id + '/' + pdb_id + '.pdb' + str(i) + '-500.jpg'
    print(img_url)

印刷品：

https://cdn.rcsb.org/images/rutgers/a6/1a69/1a69.pdb-500.jpg
https://cdn.rcsb.org/images/rutgers/a6/1a69/1a69.pdb1-500.jpg