import os.path from google.auth.transport.requests import Request from google.oauth2.credentials import Credentials from google_auth_oauthlib.flow import InstalledAppFlow SCOPES = ["https://www.googleapis.com/auth/gmail.readonly"] creds = None # The file token.json stores the user's access and refresh tokens, and is # created automatically when the authorization flow completes for the first # time. if os.path.exists("email_token.json"): creds = Credentials.from_authorized_user_file("email_token.json", SCOPES) # If there are no (valid) credentials available, let the user log in. if not creds or not creds.valid: if creds and creds.expired and creds.refresh_token: creds.refresh(Request()) else: flow = InstalledAppFlow.from_client_secrets_file( # your creds file here. Please create json file as here https://cloud.google.com/docs/authentication/getting-started "creds.json", SCOPES, ) creds = flow.run_local_server(port=0) # Save the credentials for the next run with open("email_token.json", "w") as token: token.write(creds.to_json())