Google App Engine Python

"""
Created By Egar Rizki Santuso
Concact: http://www.facebook.com/egar.isthecrime
"""
import logging, md5, urllib, urllib2


def do_auth(appname, user, password, dev=False, admin=False):
    "This is taken from bits of appcfg, specifically: "
    " google/appengine/tools/appengine_rpc.py "
    "It returns the cookie send by the App Engine Login "
    "front-end after authenticating with Google Accounts. "

    if dev:
        return do_auth_dev_appserver(user, admin)

    # get the token
    try:
        auth_token = get_google_authtoken(appname, user, password)
    except AuthError, e:
        if e.reason == "BadAuthentication":
            logging.error( "Invalid username or password." )
        if e.reason == "CaptchaRequired":
            logging.error(
                "Please go to\n"
                "https://www.google.com/accounts/DisplayUnlockCaptcha\n"
                "and verify you are a human.  Then try again.")
        if e.reason == "NotVerified":
            logging.error( "Account not verified.")
        if e.reason == "TermsNotAgreed":
            logging.error( "User has not agreed to TOS.")
        if e.reason == "AccountDeleted":
            logging.error( "The user account has been deleted.")
        if e.reason == "AccountDisabled":
            logging.error( "The user account has been disabled.")
        if e.reason == "ServiceDisabled":
            logging.error( "The user's access to the service has been "
                                 "disabled.")
        if e.reason == "ServiceUnavailable":
            logging.error( "The service is not available; try again later.")
        raise

    # now get the cookie
    cookie = get_gae_cookie(appname, auth_token)
    assert cookie
    return cookie

def do_auth_dev_appserver(email, admin):
    """Creates cookie payload data.

    Args:
    email, admin: Parameters to incorporate into the cookie.

    Returns:
    String containing the cookie payload.
    """
    admin_string = 'False'
    if admin:
        admin_string = 'True'
    if email:
        user_id_digest = md5.new(email.lower()).digest()
        user_id = '1' + ''.join(['%02d' % ord(x) for x in user_id_digest])[:20]
    else:
        user_id = ''
    return 'dev_appserver_login="%s:%s:%s"; Path=/;' % (email, admin_string, user_id)

def get_gae_cookie(appname, auth_token):
    """
    Send a token to the App Engine login, again stating the name of the
    application to gain authentication for. Returned is a cookie that may be used
    to authenticate HTTP traffic to the application at App Engine.
    """

    continue_location = "http://localhost/"
    args = {"continue": continue_location, "auth": auth_token}
    host = "%s.appspot.com" % appname
    url = "https://%s/_ah/login?%s" % (host,
                               urllib.urlencode(args))

    opener = get_opener() # no redirect handler!
    req = urllib2.Request(url)
    try:
        response = opener.open(req)
    except urllib2.HTTPError, e:
        response = e

    if (response.code != 302 or
            response.info()["location"] != continue_location):
        raise urllib2.HTTPError(req.get_full_url(), response.code,
                response.msg, response.headers, response.fp)

    cookie = response.headers.get('set-cookie')
    assert cookie and cookie.startswith('ACSID')
    return cookie.replace('; HttpOnly', '')

def get_google_authtoken(appname, email_address, password):
    """
    Make secure connection to Google Accounts and retrieve an authorisation
    token for the stated appname.

    The token can be send to the login front-end at appengine using
    get_gae_cookie(), which will return a cookie to use for the user session.
    """
    opener = get_opener()

    # get an AuthToken from Google accounts
    auth_uri = 'https://www.google.com/accounts/ClientLogin'
    authreq_data = urllib.urlencode({ "Email":   email_address,
                                      "Passwd":  password,
                                      "service": "ah",
                                      "source":  appname,
                                      "accountType": "HOSTED_OR_GOOGLE" })
    req = urllib2.Request(auth_uri, data=authreq_data)
    try:
        response = opener.open(req)
        response_body = response.read()
        response_dict = dict(x.split("=")
                             for x in response_body.split("\n") if x)
        return response_dict["Auth"]
    except urllib2.HTTPError, e:
        if e.code == 403:
            body = e.read()
            response_dict = dict(x.split("=", 1) for x in body.split("\n") if x)
            raise AuthError(req.get_full_url(), e.code, e.msg,
                                   e.headers, response_dict)
        else:
            raise

class AuthError(urllib2.HTTPError):
    """Raised to indicate there was an error authenticating."""

    def __init__(self, url, code, msg, headers, args):
        urllib2.HTTPError.__init__(self, url, code, msg, headers, None)
        self.args = args
        self.reason = args["Error"]

def get_opener(cookiejar=None):
    opener = urllib2.OpenerDirector()
    opener.add_handler(urllib2.ProxyHandler())
    opener.add_handler(urllib2.UnknownHandler())
    opener.add_handler(urllib2.HTTPHandler())
    opener.add_handler(urllib2.HTTPDefaultErrorHandler())
    opener.add_handler(urllib2.HTTPErrorProcessor())
    opener.add_handler(urllib2.HTTPSHandler())
    if cookiejar:
        opener.add_handler(urllib2.HTTPCookieProcessor(cookiejar))
    return opener