title: Get user info when someone runs Google Apps Script web app as me
body: <p>I have a standalone Google Apps Script deployed as a web app. The app is executed as me, because I want it to access files stored on my Drive, and because I want it to generate Google Sheets files that have some ranges protected from the user that are still editable by the script. However, I want these files to be segregated into folders, and each folder is assigned to a user, so I need to know who the user is each time the app runs.</p>
  
  <p>Session.getActiveUser().getEmail() doesn't work since the web app is deployed as me and not as the user. My other thought was to make the app "available to everyone, even anonymous" (right now it's just "available to everyone") to skip Google's login screen, and use some kind of third-party authentication service or script. Building my own seems like overkill because this seems like it should already exist, but so far my research has only turned up things like Auth0 which seem incompatible with my simple Google Apps Script-based app, or else I'm too inexperienced to figure out how to use them.</p>
  
  <p>Does anyone have a suggestion for how to authenticate users for this kind of web app? Preferably something that comes with a beginner-friendly tutorial or documentation? Or, is there another way for me to find out who's running the app while still executing it as myself?</p>
  
  <p>I am so new to this I'm not even sure I'm asking this question in the right way, so suggested edits are taken gratefully.</p>