email_sender.rb

class EmailSender
  def self.send_emails(number_of_emails, job_que_id)
    emails = EmailQue.where(send_status: 'NOT SENT', job_que_id: job_que_id)
    emails = emails.limit(number_of_emails) unless number_of_emails.zero?

    errors = []

    emails.each do |email|
      email_params = {
        from:    'email@example.com',     # <== change this to appropriate value
        to:      email.to_field,
        subject: email.subject_field,
        body:    email.body_field,
      }

      delivered = send_email(email_params)

      status = delivered ? 'SENT' : 'ERROR'
      email.update_attributes send_status: status

      errors << "Failed to deliver email with id=#{email.id}." unless delivered
    end

    return errors unless errors.empty?
    emails.size
  end

  # return true on successfull delivery, false otherwise
  def self.send_email(params)
    ActionMailer::Base.mail(params).deliver
  rescue StandardError
    false
  else
    true
  end
end