client_secret.json

{
  "web": {
    "client_id": "",
    "client_secret": "",
    "redirect_uris": [""],
    "auth_uri": "https://accounts.google.com/o/oauth2/auth",
    "token_uri": "https://accounts.google.com/o/oauth2/token",
    "YOUR_API_KEY": ""
  }
}