Python check if website exists

I wanted to check if a certain website exists, this is what I'm doing:

user_agent = 'Mozilla/20.0.1 (compatible; MSIE 5.5; Windows NT)'
headers = { 'User-Agent':user_agent }
link = "http://www.abc.com"
req = urllib2.Request(link, headers = headers)
page = urllib2.urlopen(req).read() - ERROR 402 generated here!

If the page doesn't exist (error 402, or whatever other errors), what can I do in the page = ... line to make sure that the page I'm reading does exit?

You can use HEAD request instead of GET. It will only download the header, but not the content. Then you can check the response status from the headers.

For python 2.7.x, you can use httplib:

import httplib
c = httplib.HTTPConnection('www.example.com')
c.request("HEAD", '')
if c.getresponse().status == 200:
   print('web site exists')

or urllib2:

import urllib2
try:
    urllib2.urlopen('http://www.example.com/some_page')
except urllib2.HTTPError, e:
    print(e.code)
except urllib2.URLError, e:
    print(e.args)

or for 2.7 and 3.x, you can install requests

import requests
response = requests.get('http://www.example.com')
if response.status_code == 200:
    print('Web site exists')
else:
    print('Web site does not exist')

It's better to check that status code is < 400, like it was done here. Here is what do status codes mean (taken from wikipedia):

1xx - informational
2xx - success
3xx - redirection
4xx - client error
5xx - server error

If you want to check if page exists and don't want to download the whole page, you should use Head Request:

import httplib2
h = httplib2.Http()
resp = h.request("http://www.google.com", 'HEAD')
assert int(resp[0]['status']) < 400

taken from this answer.

If you want to download the whole page, just make a normal request and check the status code. Example using requests:

import requests

response = requests.get('http://google.com')
assert response.status_code < 400

Python check if website exists

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