抓取：从网址下载文件

Question

我想自动从此页面下载文件。

我试过很多方法，比如：

download.file
read.table
GET

但没有成功。 我不是要求代码，但我要求任何提示/想法来处理这种情况。

Answer 1

使用BeautifulSoup Python版本。

try:
    # Python 3.x
    from urllib.request import urlopen, urlretrieve, quote
    from urllib.parse import urljoin
except ImportError:
    # Python 2.x
    from urllib import urlopen, urlretrieve, quote
    from urlparse import urljoin

from bs4 import BeautifulSoup

url = 'http://oilandgas.ky.gov/Pages/ProductionReports.aspx'
u = urlopen(url)
try:
    html = u.read().decode('utf-8')
finally:
    u.close()

soup = BeautifulSoup(html)
for link in soup.select('div[webpartid] a'):
    href = link.get('href')
    if href.startswith('javascript:'):
        continue
    filename = href.rsplit('/', 1)[-1]
    href = urljoin(url, quote(href))
    try:
        urlretrieve(href, filename)
    except:
        print('failed to download')

Answer 2

这对我有用：

getIt = function(what,when){ 
     url=paste0("http://oilandgas.ky.gov/Production%20Reports%20Library/",
                 when,"%20-%20",what,
                "%20Production.xls")
     destfile=paste0("/tmp/",what,when,".xls")
     download.file(url,destfile)
}

例如：

> getIt("gas",2006)
trying URL 'http://oilandgas.ky.gov/Production%20Reports%20Library/2006%20-%20gas%20Production.xls'
Content type 'application/vnd.ms-excel' length 3490304 bytes (3.3 Mb)
opened URL
==================================================
downloaded 3.3 Mb

除了第一个：

> getIt("oil",2010)
trying URL 'http://oilandgas.ky.gov/Production%20Reports%20Library/2010%20-%20oil%20Production.xls'
Error in download.file(url, destfile) : 
  cannot open URL 'http://oilandgas.ky.gov/Production%20Reports%20Library/2010%20-%20oil%20Production.xls'
In addition: Warning message:
In download.file(url, destfile) :
  cannot open: HTTP status was '404 NOT FOUND'

虽然我可以获得2010年的天然气数据：

> getIt("gas",2010)
trying URL 'http://oilandgas.ky.gov/Production%20Reports%20Library/2010%20-%20gas%20Production.xls'
Content type 'application/vnd.ms-excel' length 4177408 bytes (4.0 Mb)
opened URL
==================================================
downloaded 4.0 Mb

所以看起来他们改变了那个链接的系统。 您可以通过链接获取该数据，然后在cruddy Sharepoint HTML中查找下载链接。

这就是为什么我们讨厌Sharepoint，小孩。