filterLongEmails.js

//
// This function moves long emails in your Inbox to the Archive folder and warn the sender that you don't want to read too long emails.
// It could be very useful if you want to keep a clean inbox and spend less time reading and writring emails
// Just run it every 5 minutes (for example) and you'll be fine!
//
// Copyleft - Antoine AUGUSTI - www.antoine-augusti.fr - 2013
//

function filterLongEmails()
{
  // Determine how much messages we want to target in the Inbox
  var num_messages = 1;
  // What is a "too long email" according to you?
  var word_limit = 50;
  
  // About the email that will be send if we find a "too long email"
  var subject = "Shorter emails will be read";
  var content = "Hello, I am a pretty busy person and will appreciate if you can keep your email under " + word_limit + " words. Please edit and resend!";
  
  // Get the last num_messages messages in the Inbox
  var threads = GmailApp.getInboxThreads(0, num_messages);
  
  for (var i = 0; i < threads.length; i++)
  {
    // Check if we have only a message in the current thread (so that we do not stop an ongoing conversation)
    if (threads[i].isUnread() && threads[i].getMessageCount() == 1)
    {
      var message = threads[i].getMessages()[0];
      var word_count = message.getBody().split(' ').length;
      
      if (word_count > word_limit)
      {
        // If the message is NOT from a "no reply" email address, we send a message
        // If we reply to a "no reply" email address, we could have a reply from the server saying that this email address doesn't exist (and we definitely don't want that)
        if (!message.getFrom().match(/no-reply|noreply/))
        {
          GmailApp.sendEmail(message.getFrom(), subject, content);
        }
        
        // Keep our inbox clean: move this mail to the Archive folder
        GmailApp.moveThreadToArchive(threads[i]);
      }
    }
  }
};