SingleRecipientSmtp

single_recipient_smtp.rb

class SingleRecipientSmtp < ::Mail::SMTP
  def initialize(_)
    self.settings = {
      address: 'smtp.sendgrid.net',
      authentication: :plain,
      domain: 'myapp.com',
      password: ENV['SENDGRID_PASSWORD'],
      port: '587',
      user_name: ENV['SENDGRID_USERNAME']
    }
  end

  def deliver!(mail)
    mail.to.each do |recipient|
      log "*** suppressing mail to #{recipient}"
    end

    mail.to = 'staging@myapp.com'
    mail.cc = nil
    mail.bcc = nil

    super mail
  end

  def log(message)
    if defined? Rails
      Rails.logger.warn message
    end
  end
end

staging.rb

require Rails.root.join('lib', 'single_recipient_smtp')

MyApp::Application.configure do
  # ...
  config.action_mailer.delivery_method = SingleRecipientSmtp
  # ...
end