How do I use google.auth instead of oauth2client in Python to get access to my Google Calendar

According to the oauth2client deprecation notes, the replacement to be used to manage Google user credentials is google-auth-oauthlib. Below a snippet working on my PC (python 3.6).

As the documentation highlights the new library does not save the credentials, that's why I am using pickle to save them. Maybe, depending on your application requirements, you want to have a more robust solution (like a database).

import os
import pickle

from googleapiclient.discovery import build
from google_auth_oauthlib.flow import InstalledAppFlow
from google.auth.transport.requests import Request

SCOPES = ['https://www.googleapis.com/auth/calendar.readonly', ]


# we check if the file to store the credentials exists
if not os.path.exists('credentials.dat'):

    flow = InstalledAppFlow.from_client_secrets_file('client_id.json', SCOPES)
    credentials = flow.run_local_server()

    with open('credentials.dat', 'wb') as credentials_dat:
        pickle.dump(credentials, credentials_dat)
else:
    with open('credentials.dat', 'rb') as credentials_dat:
        credentials = pickle.load(credentials_dat)

if credentials.expired:
    credentials.refresh(Request())

calendar_sdk = build('calendar', 'v3', credentials=credentials)

calendars_get_params = {
        'calendarId': 'primary',
    }

test = calendar_sdk.calendars().get(**calendars_get_params).execute()
print(test)

I haven't robustly tested this, but it works for testing snippets with my personal account. I'm sure there are changes that could and/or should be made to it for enterprise applications, such as passing auth'd Http() instances, detecting scope changes, and so on.

You can review the full code on my GitHub repo:

requirements:

• google-api-python-client
• google-auth
• google-auth-oauthlib
• whatever deps the above pull in

I use the InstalledAppFlow class, and generally followed the instructions on Google's Python auth guide.

Code (Python 3.6)

# Google API imports
from googleapiclient.discovery import build
from google.oauth2.credentials import Credentials
from google_auth_oauthlib.flow import InstalledAppFlow

SCOPES = ['your scopes', 'here']

def get_saved_credentials(filename='creds.json'):
    '''Read in any saved OAuth data/tokens
    '''
    fileData = {}
    try:
        with open(filename, 'r') as file:
            fileData: dict = json.load(file)
    except FileNotFoundError:
        return None
    if fileData and 'refresh_token' in fileData and 'client_id' in fileData and 'client_secret' in fileData:
        return Credentials(**fileData)
    return None

def store_creds(credentials, filename='creds.json'):
    if not isinstance(credentials, Credentials):
        return
    fileData = {'refresh_token': credentials.refresh_token,
                'token': credentials.token,
                'client_id': credentials.client_id,
                'client_secret': credentials.client_secret,
                'token_uri': credentials.token_uri}
    with open(filename, 'w') as file:
        json.dump(fileData, file)
    print(f'Credentials serialized to {filename}.')

def get_credentials_via_oauth(filename='client_secret.json', scopes=SCOPES, saveData=True) -> Credentials:
    '''Use data in the given filename to get oauth data
    '''
    iaflow: InstalledAppFlow = InstalledAppFlow.from_client_secrets_file(filename, scopes)
    iaflow.run_local_server()
    if saveData:
        store_creds(iaflow.credentials)
    return iaflow.credentials

def get_service(credentials, service='sheets', version='v4'):
    return build(service, version, credentials=credentials)

Usage is then:

creds = get_saved_credentials()
if not creds:
    creds = get_credentials_via_oauth()
sheets = get_service(creds)