gistfile1.rb

module PaypalHelper
  PAYPAL_API_PEM = File.read(File.join(RAILS_ROOT, 'certs', 'paypal_api.pem'))

  # paypal_transfer(100.0, "yacare@example.com", "USD", "Your earnings", "This is a receipt"
  def paypal_transfer(amount, email, currency, subject = nil, note = nil)
    gateway = ActiveMerchant::Billing::PaypalGateway.new(:login => APP_CONFIG[:paypal_api_username],
                                                         :password => APP_CONFIG[:paypal_api_password],
                                                         :pem => PAYPAL_API_PEM)
    gateway.transfer amount_in_cents(amount), email,
      :subject => subject, :note => note, :currency => currency
  end

  def amount_in_cents(amount)
    (amount *100).round
  end
end