app.py

### ... new endpoint 

@app.route('/api/twitter_auth_callback', methods=["GET"])
@cross_origin()
def twitter_callback():
    try:
        oauth_token = request.args.get('oauth_token')
        oauth_verifier = request.args.get('oauth_verifier')
        auth = tweepy.OAuthHandler(consumer_key, consumer_secret)

        auth.request_token = { "oauth_token": oauth_token, "oauth_token_secret": oauth_verifier }
        auth.get_access_token(oauth_verifier)
        api = tweepy.API(auth)
        print(api)
        user = api.verify_credentials()
        username = user.screen_name
        user_id = user.id
        return json.dumps({"message":"success", "user_id": user_id, "username": username, "access_token": auth.access_token, "access_token_secret": auth.access_token_secret})
    except Exception as ex:
        print(ex)
        return json.dumps({"message":"Failed to get tokens"}), 500