如何网页抓取隐藏在选择选项下的 PDF？

Question

我正在尝试使用 python 从网站下载 >100 个 pdf。但是，这些 pdf 文件隐藏在选择选项下。例如：

• 选项 1
• 选项 2
• 选项 3 ...

那么，如果我选择选项 1，我会说谎：

• 选项 1
  • 信息 1 的可点击链接 [文件 1 的可点击链接]
  • 信息 2 的可点击链接 [文件 2 的可点击链接]
  • 信息 3 的可点击链接 [文件 3 的可点击链接]
  • 信息 4 的可点击链接 [文件 4 的可点击链接] ...
• 选项 2
• 选项 3

一旦我按下，例如，“文件 1 的可点击链接”，图片就会弹出，在弹出窗口的右上角有一个“查看 PDF”选项。现在如何为选项 1 下的每个文件循环下载 PDF？我是网络抓取的新手，非常感谢您的帮助。

谢谢！

Answer 1

您似乎可以从链接标识符自动构建 PDF Url。例如：

import requests
from bs4 import BeautifulSoup

url = "https://www12.statcan.gc.ca/census-recensement/2016/dp-pd/prof/search-recherche/lst/results-resultats.cfm?Lang=E&TABID=1&G=1&Geo1=&Code1=&Geo2=&Code2=&GEOCODE=35&type=0"
map_url = "https://www12.statcan.gc.ca/census-recensement/geo/maps-cartes/pdf/{id1}/{id2}.pdf"

soup = BeautifulSoup(requests.get(url).content, "html.parser")

for a in soup.select("a[data-dguid]"):
    id_ = a["data-dguid"]
    m = map_url.format(id1=id_[4:9], id2=id_)
    print("{:<60} {}".format(a["data-geoname"], m))

打印：

...

Map: Arthur [Population center], Ontario                     https://www12.statcan.gc.ca/census-recensement/geo/maps-cartes/pdf/S0510/2016S05100022.pdf
Map: Atikokan [Population center], Ontario                   https://www12.statcan.gc.ca/census-recensement/geo/maps-cartes/pdf/S0510/2016S05100028.pdf
Map: Attawapiskat 91A [Population center], Ontario           https://www12.statcan.gc.ca/census-recensement/geo/maps-cartes/pdf/S0510/2016S05101497.pdf
Map: Aylmer [Population center], Ontario                     https://www12.statcan.gc.ca/census-recensement/geo/maps-cartes/pdf/S0510/2016S05100030.pdf
Map: Ayr [Population center], Ontario                        https://www12.statcan.gc.ca/census-recensement/geo/maps-cartes/pdf/S0510/2016S05100031.pdf
Map: Azilda [Population center], Ontario                     https://www12.statcan.gc.ca/census-recensement/geo/maps-cartes/pdf/S0510/2016S05101498.pdf
Map: Ballantrae [Population center], Ontario                 https://www12.statcan.gc.ca/census-recensement/geo/maps-cartes/pdf/S0510/2016S05101370.pdf
Map: Barrie [Population center], Ontario                     https://www12.statcan.gc.ca/census-recensement/geo/maps-cartes/pdf/S0510/2016S05100043.pdf
Map: Barry's Bay [Population center], Ontario                https://www12.statcan.gc.ca/census-recensement/geo/maps-cartes/pdf/S0510/2016S05100044.pdf
Map: Bath [Population center], Ontario                       https://www12.statcan.gc.ca/census-recensement/geo/maps-cartes/pdf/S0510/2016S05101403.pdf

...