Learn how to validate specific users on a Web App, Google Workspace sidebar or dialogue box with Google Apps Scripts. In this tutorial, we will explore how to validate selected users to provide access to your web app. For our example, we validate users based on whether or not they have edit access to a Google Drive file ( a common occurrence). In the discussion, we will also look at alternative ways of validating emails.
Interesting solution for access control to a Apps Script web app by using a Google Doc share permissions as a proxy. The post contains all the code you need and a discussion of other approaches.