Sending emails based on intervals using Ruby on Rails

Question

I would like to be able to send a string of emails at a determined interval to different recipients.

I assign to each Contact this series of Emails called a Campaign,

Answer 1

I would create a rake task in RAILS_ROOT/lib/tasks/email.rake

namespace :email do
  desc "send emails to contacts"
  task :send do
    Email.all.each do |email|
      # if start_date is a datetime or timestamp column
      contacts = Contact.all(:conditions => ["DATE(start_date) = ?", email.days.days.ago.to_date])
      # if start_date is a date column
      contacts = Contact.all(:conditions => { :start_date => email.days.days.ago.to_date })
      contacts.each do |contact|
        #code to send the email
      end
    end
  end
end

Then I would use a cronjob to call this rake task every day at 3 a.m.:

0 3 * * * app_user cd RAILS_APP_FOLDER && RAILS_ENV=production rake email:send