Google Account Token Expiration (for Google Calendar)

→ Google APIs use the OAuth 2.0 protocol for authentication and authorization. Google supports common OAuth 2.0 scenarios such as those for a web server, installed, and client-side applications.
→ All applications follow a basic pattern when accessing a Google API using OAuth 2.0. At a high level, you follow four steps:

1. Obtain OAuth 2.0 credentials from the Google API Console.
2. Obtain an access token from the Google Authorization Server.
3. Send the access token to an API.
4. Refresh the access token, if necessary.

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