How do you test if user has Gmail access to allow sending messages using the Google Apps Script Mail Service?

Question

Google announced a change to Mail Service in Apps Script which says:

Starting on September 13, 2016, users with free public Google Accounts (consumers) and Google Apps for Education and Google Apps Free edition users, will be required to have Gmail access to send messages through Apps Script’s Mail Service

For developers of Google Add-ons that use the MailApp Service how can you test if:

the user needs Gmail enabled to use MailApp; and
if Gmail is needed it is enabled on their account

Bryan P Bryan P · Accepted Answer · 2016-03-09T21:46:48

try

var resource = AdminDirectory.Users.get(userEmail);
Logger.log(resource.isMailboxSetup);

from Directory API

or

try {
  var sent = false;
  GmailApp.sendEmail();
  sent = true;
} catch(e) { Logger.log(e); }

Logger.log(sent);

How do you test if user has Gmail access to allow sending messages using the Google Apps Script Mail Service?

2 Answers