This answer sums up what others have said below, especially RedBaron, plus adding a method I used to get to the StackOverflow Inbox using Google Accounts.
Using the Tamper Data developer tool of Firefox and logging on to StackOVerflow, one can see that OpenID works this way:
- StackOverflow requests authentication from a given service (here Google), defined in the posted data;
- Google Accounts takes over and checks for an already existing cookie as proof of authentication;
- If no cookie is found, Google requests authentication and sets a cookie;
- Once the cookie is set, StackOverflow acknowledges authentication of the user.
The above sums up the process, which in reality is more complicated, since many redirects and cookie exchanges occur indeed.
Because reproducing the same process programmatically proved somehow difficult (and that might just be my illiteracy), especially trying to hunt down the URLs to call with all locale specifics etc. I opted for loging on to Google Accounts first, getting a well deserved cookie and then login onto Stackoverflow, which would use the cookie for authentication.
This is done simply using the following Python modules: urllib, urllib2, cookielib and BeautifulSoup.
Here is the (simplified) code, it's not perfect, but it does the trick. The extended version can be found on Github.
#!/usr/bin/env python
import urllib
import urllib2
import cookielib
from BeautifulSoup import BeautifulSoup
from getpass import getpass
# Define URLs
google_accounts_url = 'http://accounts.google.com'
authentication_url = 'https://accounts.google.com/ServiceLoginAuth'
stack_overflow_url = 'https://stackoverflow.com/users/authenticate'
genuwine_url = 'https://stackoverflow.com/inbox/genuwine'
# Build opener
jar = cookielib.CookieJar()
opener = urllib2.build_opener(urllib2.HTTPCookieProcessor(jar))
def request_url(request):
'''
Requests given URL.
'''
try:
response = opener.open(request)
except:
raise
return response
def authenticate(username='', password=''):
'''
Authenticates to Google Accounts using user-provided username and password,
then authenticates to StackOverflow.
'''
# Build up headers
user_agent = 'Mozilla/5.0 (Ubuntu; X11; Linux i686; rv:8.0) Gecko/20100101 Firefox/8.0'
headers = {'User-Agent' : user_agent}
# Set Data to None
data = None
# Build up URL request with headers and data
request = urllib2.Request(google_accounts_url, data, headers)
response = request_url(request)
# Build up POST data for authentication
html = response.read()
dsh = BeautifulSoup(html).findAll(attrs={'name' : 'dsh'})[0].get('value').encode()
auto = response.headers.getheader('X-Auto-Login')
follow_up = urllib.unquote(urllib.unquote(auto)).split('continue=')[-1]
galx = jar._cookies['accounts.google.com']['/']['GALX'].value
values = {'continue' : follow_up,
'followup' : follow_up,
'dsh' : dsh,
'GALX' : galx,
'pstMsg' : 1,
'dnConn' : 'https://accounts.youtube.com',
'checkConnection' : '',
'checkedDomains' : '',
'timeStmp' : '',
'secTok' : '',
'Email' : username,
'Passwd' : password,
'signIn' : 'Sign in',
'PersistentCookie' : 'yes',
'rmShown' : 1}
data = urllib.urlencode(values)
# Build up URL for authentication
request = urllib2.Request(authentication_url, data, headers)
response = request_url(request)
# Check if logged in
if response.url != request._Request__original:
print '\n Logged in :)\n'
else:
print '\n Log in failed :(\n'
# Build OpenID Data
values = {'oauth_version' : '',
'oauth_server' : '',
'openid_username' : '',
'openid_identifier' : 'https://www.google.com/accounts/o8/id'}
data = urllib.urlencode(values)
# Build up URL for OpenID authetication
request = urllib2.Request(stack_overflow_url, data, headers)
response = request_url(request)
# Retrieve Genuwine
data = None
request = urllib2.Request(genuwine_url, data, headers)
response = request_url(request)
print response.read()
if __name__ == '__main__':
username = raw_input('Enter your Gmail address: ')
password = getpass('Enter your password: ')
authenticate(username, password)
