calendarwatch_frontend/server/googleHandler.py

import google.oauth2.credentials
import google_auth_oauthlib.flow
import googleapiclient.discovery
from googleapiclient.discovery import build

from oauthlib.oauth2 import WebApplicationClient
import flask

# Python standard libraries
import json
import os

# Third-party libraries
import flask
from flask import Flask, redirect, request, url_for
from flask_login import (
    LoginManager,
    current_user,
    login_required,
    login_user,
    logout_user,
)
import requests

from database.models import Calendar as dbCalendar
from backend import Calendar, Event

# Configuration class for the google client 
# all necessary variables and secrets are defined in this
# aswell as some helper functions
class GoogleClient():
    def __init__(self):
        self.CLIENT_SECRETS_FILE = "certificate/client_secret.json"

        with open("/home/calendarwatch/certificate/google_client.json", encoding='utf-8') as json_file:
            self.google_client = json.load(json_file)

        self.SCOPES = self.google_client.get('scopes')
        self.API_SERVICE_NAME = 'calendar'
        self.API_VERSION = 'v3'

        #  GOOGLE_CLIENT_ID ="377787187748-shuvi4iq5bi4gdet6q3ioataimobs4lh.apps.googleusercontent.com"
        self.GOOGLE_CLIENT_ID = self.google_client.get('client_id')
        # GOOGLE_CLIENT_SECRET = "Hu_YWmKsVKUcLwyeINYzdKfZ"
        self.GOOGLE_CLIENT_SECRET = self.google_client.get('client_secret')
        self.GOOGLE_DISCOVERY_URL = (
            "https://accounts.google.com/.well-known/openid-configuration"
        )

        # OAuth 2 client setup
        self.client = WebApplicationClient(self.GOOGLE_CLIENT_ID)


    def build_credentials(self, token, refresh_token):
        data = {}
        data['token'] = token
        data['refresh_token'] = refresh_token
        data['token_uri'] = self.google_client.get('token_uri')
        data['client_id'] = self.google_client.get('client_id')
        data['client_secret'] = self.google_client.get('client_secret')
        data['scopes'] = self.google_client.get('scopes')
        return data

GC = GoogleClient()

# stuff for OAuth login
def login():
    # Create flow instance to manage the OAuth 2.0 Authorization Grant Flow steps.
    flow = google_auth_oauthlib.flow.Flow.from_client_secrets_file(
        GC.CLIENT_SECRETS_FILE, scopes=GC.SCOPES)
    # The URI created here must exactly match one of the authorized redirect URIs
    # for the OAuth 2.0 client, which you configured in the API Console. If this
    # value doesn't match an authorized URI, you will get a 'redirect_uri_mismatch'
    # error.
    flow.redirect_uri = "https://longitudecalendar.com/login/google/callback" 
    authorization_url, state = flow.authorization_url(
        # Enable offline access so that you can refresh an access token without
        # re-prompting the user for permission. Recommended for web server apps.
        access_type='offline',
        # Enable incremental authorization. Recommended as a best practice.
        include_granted_scopes='true')

    # Store the state so the callback can verify the auth server response.
    flask.session['state'] = state
    # Flask-Login helper to retrieve a user from our db
    return authorization_url

def verifyResponse():
    # Specify the state when creating the flow in the callback so that it can
    # verified in the authorization server response.
    state = flask.session['state']

    flow = google_auth_oauthlib.flow.Flow.from_client_secrets_file(
        GC.CLIENT_SECRETS_FILE, scopes=GC.SCOPES, state=state)
    flow.redirect_uri = "https://longitudecalendar.com/login/google/callback" 
    
    # Use the authorization server's response to fetch the OAuth 2.0 tokens.
    authorization_response = flask.request.url
    flow.fetch_token(authorization_response=authorization_response)

    # Store credentials in the session.
    # ACTION ITEM: In a production app, you likely want to save these
    #              credentials in a persistent database instead.

    credentials = flow.credentials
    flask.session['credentials'] = credentials_to_dict(credentials)
    print(credentials_to_dict(credentials), flush=True)
    session = flow.authorized_session()
    return session, credentials_to_dict(credentials)


def get_google_provider_cfg():
    return requests.get(GC.GOOGLE_DISCOVERY_URL).json()

def deleteAccount(user):
    result = requests.post('https://oauth2.googleapis.com/revoke',
        params={'token': user.google_token.token},
        headers = {'content-type': 'applixation/x-www-form-urlencoded'})
    print(result, flush=True)
    return


def fetchCalendarEvents(user, calendars, startDate, endDate):

    client_token = GC.build_credentials(user.google_token.token,
                                        user.google_token.refresh_token)
    credentials = google.oauth2.credentials.Credentials(**client_token)

    service = build(GC.API_SERVICE_NAME, GC.API_VERSION, credentials=credentials)
    
    all_events = []
    for calendar in calendars:
        if calendar.toggle == "True":
            event_result = service.events().list(calendarId=calendar.calendar_id, 
                                                 timeMin=startDate,
                                                 timeMax=endDate,
                                                 maxResults=10, 
                                                 singleEvents=True,
                                                 orderBy='startTime').execute()

            for event in event_result.get('items', []):
                
                # create simple event
                name = event.get('summary', '(no Title)')
                start = event['start'].get('dateTime')
                end = event['end'].get('dateTime')
                newEvent = Event(name, start, end)

                # handle weird colors from google
                color = event.get('colorId')
                if color == None:
                    newEvent.colorHex = calendar.color
                    newEvent.eventColorId = None
                else:
                    newEvent.eventColorId = color
                
                all_events.append(newEvent)

    colors = service.colors().get().execute()

    return all_events, colors


def fetchCalendars():
    # get client api service
    if current_user.google_token == None:
        return [], None, None
    client_token = GC.build_credentials(current_user.google_token.token,
                                        current_user.google_token.refresh_token)
    credentials = google.oauth2.credentials.Credentials(**client_token)

    service = build(GC.API_SERVICE_NAME, GC.API_VERSION, credentials=credentials)
   
    # get all calendars and put them into Calendar Class
    page_token = None
    calendars = []
    while True:
        calendar_list = service.calendarList().list(pageToken=page_token).execute()
        for calendar in calendar_list['items']:
            calendars.append(Calendar(name=calendar['summary'], 
                                              calendarId=calendar['id'], 
                                              color=calendar['colorId']))
        page_token = calendar_list.get('nextPageToken')
        if not page_token:
            break


    colors = service.colors().get().execute()

    return calendars, colors, credentials.token
        


def getUserCredentials(user):
    credentials = GC.build_credentials(user.google_token.token,
                                        user.google_token.refresh_token)
    googleCreds = google.oauth2.credentials.Credentials(**credentials)                                        
    return googleCreds



def credentials_to_dict(credentials):
  return {'token': credentials.token,
          'refresh_token': credentials.refresh_token,
          'token_uri': credentials.token_uri,
          'client_id': credentials.client_id,
          'client_secret': credentials.client_secret,
          'scopes': credentials.scopes}