google-auth

Infra Google Auth

Google OAuth setup, refresh tokens, troubleshooting

When to use

• "Google API is not working"
• "401 Unauthorized"
• "token expired"
• Setting up a new project

Paths

What	Path
Credentials	$GOOGLE_TOOLS_PATH/credentials.json
Token	$GOOGLE_TOOLS_PATH/token.json

Scopes (permissions)

SCOPES = [
    'https://www.googleapis.com/auth/gmail.send',
    'https://www.googleapis.com/auth/gmail.readonly',
    'https://www.googleapis.com/auth/spreadsheets',
    'https://www.googleapis.com/auth/calendar',
    'https://www.googleapis.com/auth/documents',
    'https://www.googleapis.com/auth/drive',
]

How to use existing token

import json
from google.oauth2.credentials import Credentials
from googleapiclient.discovery import build

with open('$GOOGLE_TOOLS_PATH/token.json', 'r') as f:
    token_data = json.load(f)

creds = Credentials(
    token=token_data.get('token'),
    refresh_token=token_data.get('refresh_token'),
    token_uri=token_data.get('token_uri'),
    client_id=token_data.get('client_id'),
    client_secret=token_data.get('client_secret')
)

# Gmail
gmail = build('gmail', 'v1', credentials=creds)

# Sheets
sheets = build('sheets', 'v4', credentials=creds)

# Drive
drive = build('drive', 'v3', credentials=creds)

Refresh token manually

from google.auth.transport.requests import Request

if creds.expired and creds.refresh_token:
    creds.refresh(Request())

    # Save the updated token
    with open('$GOOGLE_TOOLS_PATH/token.json', 'w') as f:
        json.dump({
            'token': creds.token,
            'refresh_token': creds.refresh_token,
            'token_uri': creds.token_uri,
            'client_id': creds.client_id,
            'client_secret': creds.client_secret,
        }, f)

Create a new token (if the old one doesn't work)

from google_auth_oauthlib.flow import InstalledAppFlow

SCOPES = [...]  # all required scopes

flow = InstalledAppFlow.from_client_secrets_file(
    '$GOOGLE_TOOLS_PATH/credentials.json',
    SCOPES
)
creds = flow.run_local_server(port=0)

# Save
with open('$GOOGLE_TOOLS_PATH/token.json', 'w') as f:
    json.dump({
        'token': creds.token,
        'refresh_token': creds.refresh_token,
        'token_uri': creds.token_uri,
        'client_id': creds.client_id,
        'client_secret': creds.client_secret,
    }, f)

Common API calls

Reading Sheets

result = sheets.spreadsheets().values().get(
    spreadsheetId='SPREADSHEET_ID',
    range="'Sheet Name'!A1:Z100"
).execute()
rows = result.get('values', [])

Writing to Sheets

sheets.spreadsheets().values().update(
    spreadsheetId='SPREADSHEET_ID',
    range="'Sheet Name'!A1",
    valueInputOption='RAW',
    body={'values': [['value1', 'value2']]}
).execute()

Sending Email

import base64
from email.mime.text import MIMEText

message = MIMEText('Body text', 'plain', 'utf-8')
message['to'] = '[email protected]'
message['from'] = 'Your Name <[email protected]>'
message['subject'] = 'Subject'

raw = base64.urlsafe_b64encode(message.as_bytes()).decode()
gmail.users().messages().send(userId='me', body={'raw': raw}).execute()

Troubleshooting

Problem	Solution
401 Unauthorized	Refresh token or create a new one
invalid_grant	Token revoked, create a new one
Scope mismatch	Load token without scope verification
RefreshError	Create a new token via OAuth flow

Account

• Email: [email protected]
• Type: Google Workspace

Related skills

• email-send-direct -- single email via Gmail API
• email-send-bulk -- bulk email via Gmail API
• telegram-send -- reads Sheets for data