title: Invoking Google App script programatically and user identity?
body: <p>Google app script can be deployed as web app and triggered when you access given url.</p>
  
  <p>When you trigger google app script programatically (e.g. from google engine application) how you can specify 'user context' ? Any special headers parameters ? </p>
  
  <p>From browser it works  seamlessly : you are logged in your google account and when you visit google app script on your app domain it`s triggered and executed in your 'user context'. How doest that works ?</p>