SSO react-google-login with google on react app using a react component

I got question about implementing google login. I was able to implement Google Login button on my react app using an open source library called [react-google-login][1]. I was able to set up the backend server using python flask, and host the api on Heroku: http://arrangement-server.herokuapp.com/login. The client side should just be redirecting to google and then getting a token when it redirects back. But I have trouble to getting any token from Google login information on the frontend through react component.
I think there's an issue with my header for access token and request from [app.py][2]

google = oauth.remote_app('google',
                          base_url='https://www.google.com/accounts/',
                          authorize_url='https://accounts.google.com/o/oauth2/auth',
                          request_token_url=None,
                          request_token_params={'scope': 'https://www.googleapis.com/auth/userinfo.email',
                                                'response_type': 'code'},
                          access_token_url='https://accounts.google.com/o/oauth2/token',
                          access_token_method='POST',
                          access_token_params={'grant_type': 'authorization_code'},
                          consumer_key=GOOGLE_CLIENT_ID,
                          consumer_secret=GOOGLE_CLIENT_SECRET)


@app.route("/")
def home_page():
    access_token = session.get('access_token')
    if access_token is None:
        return redirect(url_for('login'))

    access_token = access_token[0]
    from urllib2 import Request, urlopen, URLError

    headers = {'Authorization': 'OAuth '+access_token}
    req = Request('https://www.googleapis.com/oauth2/v1/userinfo',
                  None, headers)
    try:
        res = urlopen(req)
    except URLError, e:
        if e.code == 401:
            # Unauthorized - bad token
            session.pop('access_token', None)
            return redirect(url_for('login'))
        return res.read()

    return res.read()

my react component at App.js

import React, { Component } from 'react'
import './App.css'
import router from 'config/router'
import { Provider } from 'react-redux'
import store from 'store/index'
import { GoogleLogin } from 'react-google-login'
import config from './config.json'

class App extends Component {

    constructor() {
        super();
        this.state = { isAuthenticated: false, user: null, token:
            ''};
    }
    logout = () => {
        this.setState({isAuthenticated: false, token: '', user: null})
    };

    onFailure = (error) => {
        alert(error);
    };

    googleResponse = (response) => {
        console.log(response);
        const tokenBlob = new Blob([JSON.stringify({access_token: response.accessToken}, null, 2)], {type : 'application/json'});
        const options = {
            method: 'POST',
            body: tokenBlob,
            mode: 'cors',
            cache: 'default'
        };
        fetch('http://arrangement-server.herokuapp.com/login', options).then(r => {
            const token = r.headers.get('x-auth-token');
            r.json().then(user => {
                if (token) {
                    this.setState({isAuthenticated: true, user, token})
                }
            });
        })
    };

    render() {
        let content = !!this.state.isAuthenticated ?
            (
                <div>
                    <p>Authenticated</p>
                    <div>
                        {this.state.user.email}
                    </div>
                    <div>
                        <button onClick={this.logout} className="button">
                            Log out
                        </button>
                    </div>
                </div>
            ) :
            (
                <div>
                    <GoogleLogin
                        clientId={config.GOOGLE_CLIENT_ID}
                        buttonText="Login"
                        onSuccess={this.googleResponse}
                        onFailure={this.onFailure}
                    />
                </div>
            );

        return (
            <div className="App">
                {content}
            </div>
        );
    }
}



export default App

Code above can be found at my project