Python Web Scraping - urlopen error [Errno -2] Name or service not known

Question

I am trying to extract data from Civic Commons Apps link for my project. I am able to obtain the links of the page that I need. But when I try to open the links I get "urlopen error [Errno -2] Name or service not known"

The web scraping python code:

from bs4 import BeautifulSoup
from urlparse import urlparse, parse_qs
import re
import urllib2
import pdb

base_url = "http://civiccommons.org"
url = "http://civiccommons.org/apps"
page = urllib2.urlopen(url)
soup = BeautifulSoup(page.read())

list_of_links = [] 

for link_tag in soup.findAll('a', href=re.compile('^/civic-function.*')):
   string_temp_link = base_url+link_tag.get('href')
   list_of_links.append(string_temp_link)

list_of_links = list(set(list_of_links)) 

list_of_next_pages = []
for categorized_apps_url in list_of_links:
   categorized_apps_page = urllib2.urlopen(categorized_apps_url)
   categorized_apps_soup = BeautifulSoup(categorized_apps_page.read())

   last_page_tag = categorized_apps_soup.find('a', title="Go to last page")
   if last_page_tag:
      last_page_url = base_url+last_page_tag.get('href')
      index_value = last_page_url.find("page=") + 5
      base_url_for_next_page = last_page_url[:index_value]
      for pageno in xrange(0, int(parse_qs(urlparse(last_page_url).query)['page'][0]) + 1):
         list_of_next_pages.append(base_url_for_next_page+str(pageno))
      
   else:
      list_of_next_pages.append(categorized_apps_url)

I get the following error:

urllib2.urlopen(categorized_apps_url)
  File "/usr/lib/python2.7/urllib2.py", line 126, in urlopen
    return _opener.open(url, data, timeout)
  File "/usr/lib/python2.7/urllib2.py", line 400, in open
    response = self._open(req, data)
  File "/usr/lib/python2.7/urllib2.py", line 418, in _open
    '_open', req)
  File "/usr/lib/python2.7/urllib2.py", line 378, in _call_chain
    result = func(*args)
  File "/usr/lib/python2.7/urllib2.py", line 1207, in http_open
    return self.do_open(httplib.HTTPConnection, req)
  File "/usr/lib/python2.7/urllib2.py", line 1177, in do_open
    raise URLError(err)
urllib2.URLError:

Should I take care of anything specific when I perform urlopen? Because I don't see a problem with the http links that I get.

[edit] On second run I got the following error:

 File "/usr/lib/python2.7/urllib2.py", line 126, in urlopen
    return _opener.open(url, data, timeout)
  File "/usr/lib/python2.7/urllib2.py", line 400, in open
    response = self._open(req, data)
  File "/usr/lib/python2.7/urllib2.py", line 418, in _open
    '_open', req)
  File "/usr/lib/python2.7/urllib2.py", line 378, in _call_chain
    result = func(*args)
  File "/usr/lib/python2.7/urllib2.py", line 1207, in http_open
    return self.do_open(httplib.HTTPConnection, req)
  File "/usr/lib/python2.7/urllib2.py", line 1177, in do_open
    raise URLError(err)

The same code runs fine in my friend's Mac, but fails in my ubuntu 12.04.

Also I tried running the code in scraper wiki and it finished successfully. But few url's were missing (when compared to mac). Are there any reason for these behavior?

Python Web Scraping - urlopen error [Errno -2] Name or service not known

2 Answers