emails.rake

 desc "Log in to the Gmail account and cleanse anyone who appears to have bounced"
  task :handle_bounces => :environment do
    require 'gmail'
    # Open a connection using your default smtp settings, could also define via YML or inline
    gmail = Gmail.connect!(ActionMailer::Base.smtp_settings[:user_name], ActionMailer::Base.smtp_settings[:password])
      # Find everything from the Gmail mailer daemon (unread only)
      emails = gmail.inbox.emails(:unread, :from => "[email protected]", :subject => "Delivery Status Notification (Failure)")
      Rails.logger.info("Found #{emails.length} messages")
      emails.each do |email|
        # Gmail sets a header "X-Failed-Recipients", with each email that failed
        if !email.header["X-Failed-Recipients"].blank?
          bad_addresses = email.header["X-Failed-Recipients"].value.split(",")
          bad_addresses.each do |bad_addr|
            Rails.logger.info("looking for user with email: #{bad_addr}")
            # We assume you have a user model, but could also do whatever you want with the bad address here
            user = User.find_by_email(bad_addr)
            if user
              Rails.logger.info("Found: #{user.name}, resetting email address")
              user.email = nil # Reset the email, might vary for your use case
              user.save
            end
          end # close emails form header
          email.read! # Mark as read so we don't try to deal with it again next time
        end
      end # next email
    gmail.logout # done!
  end