PayPal Express

gistfile1.txt

::PAYPAL_OPTIONS = {
  :user => "xxx",
  :pwd => "xxx",
  :signature => "xxx",
  :version => '57.0',
}
::PAYPAL_API_URL = 'https://api-3t.paypal.com/nvp'
::PAYPAL_TOKEN_URL = 'https://www.paypal.com/cgi-bin/webscr?cmd=_express-checkout&token='

def paypal_express
  
  token = params[:token]
  payer_id = params[:PayerID]
  
  if !token.blank? && !payer_id.blank?
    
    @order = # look up in my Order model for the record based on the token
    ::PAYPAL_OPTIONS.merge!({
      :method         => 'DoExpressCheckoutPayment',
      :PAYMENTACTION  => 'Sale',
      :token          => token,
      :PAYERID        => payer_id
    })
    response = RestClient.post ::PAYPAL_API_URL, ::PAYPAL_OPTIONS   # yes, you need the RestClient Gem, get it on http://rubygems.org
    success = (CGI.parse(response)["ACK"][0] == "Success")
    # I Then do something with "success" of course, but it has nothing to do with PayPal anymore... One might just retry or reset the user to the "SetExpressCheckout"
    
  else
    
    order = # look up in my Order model for the record based on some ID in "param"
    amount = # compute the amount - has to send it as "units" (aka USD or EUR) not as "cents", contrary to AM
    tax_amount = # compute the tax, based on amount and the tax coefficient (VAT 19% in Germany for ex.)
    shipping_amount = # got this from the databse
    
    ::PAYPAL_OPTIONS.merge!({
      :method       => "SetExpressCheckout",
      :amt          => "%.2f" % (amount + tax_amount + shipping_amount),
      :L_NAME0      => "article name",
      :L_AMT0       => "%.2f" % amount,
      :L_QTY0       => 1,
      :ITEMAMT      => "%.2f" % amount,
      :TAXAMT       => "%.2f" % tax_amount,
      :SHIPPINGAMT  => "%.2f" % shipping_amount,        
      :CURRENCYCODE => "EUR", # I got this from the database in reality.
      :returnurl    => paypal_express_new_order_url,
      :cancelurl    => home_url,
      :token        => nil
    })
    
    response = RestClient.post ::PAYPAL_API_URL, ::PAYPAL_OPTIONS
    @token = CGI.parse(response)["TOKEN"][0]
    
    if @token.nil?
      # Do whatever. I just display a message and redirect... Remember I'm doing this from an iPhone app so I can display an alert and refetch the page in background
    else  
      order.update_attribute(:express_token, @token)
      redirect_to ::PAYPAL_TOKEN_URL + @token
    end
    
  end
  
end