from flask import Flask, abort, flash, make_response, render_template, jsonify, request, redirect, session, url_for
from flask_dance.contrib.google import make_google_blueprint, google
from flask_mongoengine import MongoEngine, MongoEngineSessionInterface


app = Flask(__name__, subdomain_matching=True)
app.config.from_pyfile('flask.cfg')

db = MongoEngine(app)
app.session_interface = MongoEngineSessionInterface(db)


# Auth blueprints

google_blueprint = make_google_blueprint(
    client_id="*****",
    client_secret="****",
    scope=[
        "https://www.googleapis.com/auth/plus.me",
        "https://www.googleapis.com/auth/userinfo.email",
    ],
    redirect_to='auth_google'
)

app.register_blueprint(google_blueprint, url_prefix="/login")


@app.route('/google')
def auth_google():
    if not google.authorized:
        return redirect(url_for("google.login"))
    resp = google.get("/oauth2/v2/userinfo")
    assert resp.ok, resp.text
    return "You are {email} on Google".format(email=resp.json()["email"])

Traceback (most recent call last):
  File "/home/cesar/Development/project/services/frontend_service/venv/lib/python3.7/site-packages/flask/app.py", line 2309, in __call__
    return self.wsgi_app(environ, start_response)
  File "/home/cesar/Development/project/services/frontend_service/venv/lib/python3.7/site-packages/flask/app.py", line 2295, in wsgi_app
    response = self.handle_exception(e)
  File "/home/cesar/Development/project/services/frontend_service/venv/lib/python3.7/site-packages/flask/app.py", line 1741, in handle_exception
    reraise(exc_type, exc_value, tb)
  File "/home/cesar/Development/project/services/frontend_service/venv/lib/python3.7/site-packages/flask/_compat.py", line 35, in reraise
    raise value
  File "/home/cesar/Development/project/services/frontend_service/venv/lib/python3.7/site-packages/flask/app.py", line 2292, in wsgi_app
    response = self.full_dispatch_request()
  File "/home/cesar/Development/project/services/frontend_service/venv/lib/python3.7/site-packages/flask/app.py", line 1815, in full_dispatch_request
    rv = self.handle_user_exception(e)
  File "/home/cesar/Development/project/services/frontend_service/venv/lib/python3.7/site-packages/flask/app.py", line 1718, in handle_user_exception
    reraise(exc_type, exc_value, tb)
  File "/home/cesar/Development/project/services/frontend_service/venv/lib/python3.7/site-packages/flask/_compat.py", line 35, in reraise
    raise value
  File "/home/cesar/Development/project/services/frontend_service/venv/lib/python3.7/site-packages/flask/app.py", line 1813, in full_dispatch_request
    rv = self.dispatch_request()
  File "/home/cesar/Development/project/services/frontend_service/venv/lib/python3.7/site-packages/flask/app.py", line 1799, in dispatch_request
    return self.view_functions[rule.endpoint](**req.view_args)
  File "/home/cesar/Development/project/services/frontend_service/app.py", line 237, in auth_google
    if not google.authorized:
  File "/home/cesar/Development/project/services/frontend_service/venv/lib/python3.7/site-packages/werkzeug/local.py", line 347, in __getattr__
    return getattr(self._get_current_object(), name)
  File "/home/cesar/Development/project/services/frontend_service/venv/lib/python3.7/site-packages/flask_dance/consumer/requests.py", line 129, in authorized
    self.load_token()
  File "/home/cesar/Development/project/services/frontend_service/venv/lib/python3.7/site-packages/flask_dance/consumer/requests.py", line 101, in load_token
    self._client.token = self.token
  File "/home/cesar/Development/project/services/frontend_service/venv/lib/python3.7/site-packages/lazy/lazy.py", line 28, in __get__
    value = self.__func(inst)
  File "/home/cesar/Development/project/services/frontend_service/venv/lib/python3.7/site-packages/flask_dance/consumer/requests.py", line 98, in token
    return self.blueprint.token
  File "/home/cesar/Development/project/services/frontend_service/venv/lib/python3.7/site-packages/flask_dance/consumer/base.py", line 102, in token
    _token["expires_in"] = expires_in.total_seconds()
  File "/home/cesar/Development/project/services/frontend_service/venv/lib/python3.7/site-packages/mongoengine/base/datastructures.py", line 46, in __setitem__
    self._mark_as_changed(key)
  File "/home/cesar/Development/project/services/frontend_service/venv/lib/python3.7/site-packages/mongoengine/base/datastructures.py", line 91, in _mark_as_changed
    if hasattr(self._instance, '_mark_as_changed'):
ReferenceError: weakly-referenced object no longer exists

if not google.authorized:

# app.session_interface = app.session_interface = MongoEngineSessionInterface(db)(db)