review-automation-server/gauth/views.py

from django.http import HttpResponse
from django.shortcuts import redirect
from django.urls import reverse
import google_auth_oauthlib.flow
from django.contrib.auth.decorators import login_required

from .models import UserModel


@login_required
def index(request):
    if 'credentials' not in request.session:
        return redirect(reverse('authorize'))
    cred = request.session['credentials']
    return HttpResponse(cred['access_token'])


CLIENT_SECRETS_FILE = "client_secrets.json"
SCOPES = ['https://www.googleapis.com/auth/analytics.readonly']
flow = google_auth_oauthlib.flow.Flow.from_client_secrets_file(
        CLIENT_SECRETS_FILE,
        scopes=SCOPES,
        redirect_uri="http://127.0.0.1:8000/oauth2callback")


def authorize(request):
    authorization_url, state = flow.authorization_url(access_type='offline')

    # Store the state so the callback can verify the auth server response.
    request.session['state'] = state

    return redirect(authorization_url)


def oauth2callback(request):
    state = request.session['state']

    flow.state = state
    code = request.GET.get('code', False)
    flow.fetch_token(code=code)

    credentials = flow.credentials
    request.session['credentials'] = credentials_to_dict(credentials)
    refresh_token = credentials.refresh_token
    user_model = UserModel.objects.create(user=request.user, refresh_token=refresh_token)
    user_model.save()
    return redirect(reverse('home'))


def credentials_to_dict(credentials):
    expiry = str(credentials.expiry.utcnow())
    return {
        'access_token': credentials.token,
        'expiry': expiry
    }