Determine current user in Apps Script

Question

I\'m trying to identify current user\'s name to make notes of who edited what like this:

  r.setComment(\"Edit at \" + (new Date()) + \" by \" + Session.getA         


        

Answer 1

I had trouble with Wim den Herder's solution when I used scripts running from triggers. Any non script owner was unable to edit a protected cell. It worked fine if the script was run from a button. However I needed scripts to run periodically so this was my solution:

When a user uses the sheet the first time he/she should click a button and run this:

function identifyUser(){
   var input = Browser.inputBox('Enter User Id which will be used to save user to events (run once)');
  PropertiesService.getUserProperties().setProperty("ID", input);
}

This saves the user's input to a user property. It can be read back later at any time with this code:

var user = PropertiesService.getUserProperties().getProperty("ID");