Rails Mail background sender

rails_background_sender.rb

module BackgroundSender
  def self.serialize_mail(mail)
    s = ""
    # Mail#encoded strips bcc so we must add it manually
    s << "Bcc: #{mail.bcc.join(", ")}\r\n" if mail.bcc.present?
    s << mail.encoded
    s
  end

  def self.deserialize_mail(serialized_mail)
    Mail.new(serialized_mail)
  end

  class DeliveryMethod
    attr_accessor :settings

    def initialize(options = {})
      self.settings = options
    end

    def deliver!(mail)
      Rails.logger.info "BackgroundSender#deliver! => #{mail}"
      serialized_mail = BackgroundSender.serialize_mail(mail)
      SendEmailJob.new(serialized_mail).enqueue
    end
  end
end

class SendEmailJob

  # executed when the job is popped off the queue
  def perform(serialized_mail)
    mail = BackgroundSender.deserialize_mail(serialized_mail)
    logger.info "Sending mail: #{mail}"
    deliver_mail(mail)
  rescue => e
    logger.error "Failed sending mail: #{serialized_mail}, error: #{e.inspect}"
  end

  private

  def deliver_mail(mail)
    mail.delivery_method(:smtp, self.class.smtp_settings)
    mail.deliver
  end

  def self.smtp_settings
    @smtp_settings ||= Rails.configuration.action_mailer.smtp_settings || {}
  end

end
# in an initializer
mailer_config = Rails.application.config.action_mailer
mailer_config.add_delivery_method(:async_smtp, BackgroundSender::DeliveryMethod)
ActionMailer::Base.add_delivery_method(:async_smtp, BackgroundSender::DeliveryMethod)
# in an environments file
Rails.application.configure do
  config.action_mailer.delivery_method = :async_smtp
end