Expanding on jonathanberi's comment,
As on this answer Google has deprecated the Oauth1 and OpenId. Google recommend using OAuth2 for all marketplace apps, especially after the new experience announcement
Here is some sample code
def get(self, *args, **kwargs):
code = self.get_argument('code', None)
error = self.get_argument('error',None)
redirect_uri = "{protocol}://{host}{path}".format( protocol = self.request.protocol,
host = self.request.host,
path = self.request.path)
flow = OAuth2WebServerFlow(
client_id = config['CLIENT_ID'],
client_secret= config['CLIENT_SECRET'],
scope = 'https://www.googleapis.com/auth/userinfo.email',
redirect_uri = redirect_uri,
access_type = 'online'
)
if code is None:
auth_uri = flow.step1_get_authorize_url()
self.redirect(auth_uri)
elif error:
self.redirect("http://error.com")
else:
credentials = flow.step2_exchange(code)
http = httplib2.Http()
http = credentials.authorize(http)
service = build('oauth2', 'v2', http=http)
user = service.userinfo().get().execute()