Use httplib to check if a URL will return a certain page?

Question

Im going through several hundred bit.ly links to see if they have been used to shorten a link. If a link has not, it returns this page.

How can I iterate through a list of links to check which ones do NOT return this page?

I tried using the head method used in this question, however that always returned true, of course.

I looked into the head method, but found out that it never returns any data:

>>> import httplib
>>> conn = httplib.HTTPConnection("www.python.org")
>>> conn.request("HEAD","/index.html")
>>> res = conn.getresponse()
>>> print res.status, res.reason
200 OK
>>> data = res.read()
>>> print len(data)
0
>>> data == ''
True

I'm stumped on this, and any help would be great.

Answer 1

If bit.ly returns 404 http code for non-shorten links:

#!/usr/bin/env python
from httplib import HTTPConnection
from urlparse import urlsplit

urls = ["http://bit.ly/NKEIV8", "http://bit.ly/1niCdh9"]
for url in urls:
    host, path = urlsplit(url)[1:3]
    conn = HTTPConnection(host)
    conn.request("HEAD", path)
    r = conn.getresponse()
    if r.status != 404:
       print("{r.status} {url}".format(**vars()))

Unrelated: to speed up the check, you could use multiple threads:

#!/usr/bin/env python
from httplib import HTTPConnection
from multiprocessing.dummy import Pool # use threads
from urlparse import urlsplit

def getstatus(url):
    try:
        host, path = urlsplit(url)[1:3]
        conn = HTTPConnection(host)
        conn.request("HEAD", path)
        r = conn.getresponse()
    except Exception as e:
        return url, None, str(e) # error
    else:
        return url, r.status, None

p = Pool(20) # use 20 concurrent connections
for url, status, error in p.imap_unordered(getstatus, urls):
    if status != 404:
       print("{status} {url} {error}".format(**vars()))