app-script-delete-old-emails.js

/*
 * IMPORTANT: THIS FILE SHOULD NEVER BE SHARED AS IT COULD POTENTIALLY
 *            BE A MAJOR SECURITY HOLE, ALLOWING SOMEONE WITH ACCESS THE
 *            ABILITY TO MANIPULATE AND SEE ANYTHING INSIDE OF GMAIL
 *
 * BY: LUKE RYAN JERNEJCIC
 * WEBSITE: https://lukeryan.org
 * LICENSE: GPLv3
 *
 * This is a very dangerous file. Any gmail filter in here is used to delete
 * all of the matching emails. To add some safeguards, the filter only acts
 * on messages inside the inbox, and the filter must have an `older_than:`
 * filter on it to help enforce intentionality. 
 *
 * The filters should never be intended to act on incoming mail. You can use
 * Gmail's built in functionality. The purpose of these filters are to delete
 * messages that are of interest, but start clogging up the inbox over time. 
 * For example, newsletters that you're interested in, but don't always get
 * time for and don't need requiring viewing.
 */

var emailLogsTo = 'test@test.com';
var filterForInsideCom = 'label:inbox {from:x@x.x from:r@r.r} older_than:12h';

function deleteEmailsForFilter(filter) {
  Logger.log('>> START Processing deletion of emails using filter `' + filter + '`');
  
  if (typeof filter !== 'string' || filter.length < 10) {
    Logger.log('Bad filter received. Aborting deletion of emails');
    return -1;
  }
  if (filter.indexOf('label:inbox') < 0) {
    Logger.log('Bad filter received. Will only delete emails from inbox. This is all for some overlab in time for the user to see the message.');
    return -1;
  }
  if (filter.indexOf('older_than:') < 0) {
    Logger.log('Bad filter received. Requires filter to specify an `older_than:` filter to allow for the user time to see emails.');
    return -1;
  }
  
  var emails = GmailApp.search(filter);
  Logger.log('Found ' + emails.length + ' emails');
  for (var i = 0; i < emails.length; i++) {
    var e = emails[i];
    var messages = e.getMessages();
    var desc = 'from "'+ e.getMessages()[0].getFrom() + '" with subject "' + e.getFirstMessageSubject() + '"';
    
    if (messages.length > 1) {
      Logger.log('Won\'t delete threads with more than 1 message. Skipping ' + desc);
    } else {
      Logger.log('Moving email to trash ' + desc);
      e.moveToTrash();
    }
  }
  Logger.log('<< COMPLETED');
  
  return emails.length;
}

function deleteEmailsForFilters(filters) {
  var count = 0;
  
  if (typeof filters !== 'object' || filters.constructor.name !== Array.prototype.constructor.name) {
    Logger.log('Must pass in an array of filters.');
    return -1;
  }
  
  for (var i = 0; i < filters.length; i++) {
    var c = deleteEmailsForFilter(filters[i]);
    
    if (c > 0) {
      count += c
    } else if (c < 0) {
      return -1;
    }
  }
  
  return count;
}

var lineStyle = 'margin: 5px 0; background: rgb(249,249,249); background: linear-gradient(135deg, rgba(249,249,249,1) 0%, rgba(188,244,255,1) 100%);';

function run() {
  var emailsProcessed = deleteEmailsForFilters([filterForInsideCom]);
  Logger.log('Processed %s emails.', emailsProcessed);
  if (emailsProcessed !== 0) {
    Logger.log('Sending notification email.');
    var subject = '[App Script] Auto deleted '+ emailsProcessed + ' emails';
    var body = HtmlService
                 .createHtmlOutput('<div style="' + lineStyle + '">' + Logger.getLog().replace(/[\n\r]/g, '</div><div style="' + lineStyle + '">') + '</div>')
                 .getContent();
    MailApp.sendEmail(emailLogsTo, subject, Logger.getLog(), {htmlBody: body});
    Logger.log('Completed sending email.');
  } else {
    Logger.log('Nothing to report. Move along...');
  }
}