from google.appengine.api import urlfetch
from urllib import urlencode
email = request.POST['username']
passwd = request.POST['password']
serv_root = "http://myapp.appspot.com"
target = 'http://myapp.appspot.com/null'
app_name = "myapp-1.0"
auth_uri = 'https://www.google.com/accounts/ClientLogin'
authreq_data = urlencode({ "Email":   email,
                                  "Passwd":  passwd,
                                  "service": "ah",
                                  "source":  app_name,
                                  "accountType": "HOSTED_OR_GOOGLE" })
result = urlfetch.fetch(auth_uri, authreq_data, method=urlfetch.POST,
follow_redirects=False)
auth_dict = dict(x.split("=") for x in result.content.split("\n") if
x)
auth_token = auth_dict["Auth"]
serv_args = {}
serv_args['continue'] = target
serv_args['auth']     = auth_token
serv_uri = "%s/_ah/login?%s" % (serv_root, urlencode(serv_args))
result2 = urlfetch.fetch(serv_uri, follow_redirects=False,
method=urlfetch.GET)
### here's the cookie which will authenticate future requests
cookie = result2.headers['set-cookie'].split(';')[0]
# cookie[0] => "ACSID"
# cookie[1] => "AAAAHFSDJHSDFHSDJFHSDJFHSJFSDfsdjfhsjdfhsjdfh..."