Rails passing object to class in modules directory paypal-sdk-merchant - ruby-on-rails

Question

I am following the guide at http://www.tommyblue.it/2013/07/03/paypal-express-checkout-with-ruby-on-rails-and-paypal-sdk-merchant ;and, when I try to pass the order to the paypal_interface, I get a nil object.
def show
#order = Order.find(params[:id])
#paypal = PaypalInterface.new(#order)
#paypal.express_checkout
if #paypal.express_checkout_response.success?
#paypal_url = #paypal.api.express_checkout_url(#paypal.express_checkout_response)
else
# manage error
end
end
edit to include entire file
paypal_interface.rb
require 'paypal-sdk-merchant'
class PaypalInterface
attr_reader :api, :express_checkout_response
PAYPAL_RETURN_URL = Rails.application.routes.url_helpers.paid_orders_url(host: HOST_WO_HTTP)
PAYPAL_CANCEL_URL = Rails.application.routes.url_helpers.revoked_orders_url(host: HOST_WO_HTTP)
PAYPAL_NOTIFY_URL = Rails.application.routes.url_helpers.ipn_orders_url(host: HOST_WO_HTTP)
def initialize(order)
#api = PayPal::SDK::Merchant::API.new
#order = order
end
#set_express_checkout = #api.build_set_express_checkout({
SetExpressCheckoutRequestDetails: {
ReturnURL: PAYPAL_RETURN_URL,
CancelURL: PAYPAL_CANCEL_URL,
PaymentDetails: [{
NotifyURL: PAYPAL_NOTIFY_URL,
OrderTotal: {
currencyID: "EUR",
value: #order.total
},
ItemTotal: {
currencyID: "EUR",
value: #order.total
},
ShippingTotal: {
currencyID: "EUR",
value: "0"
},
TaxTotal: {
currencyID: "EUR",
value: "0"
},
PaymentDetailsItem: [{
Name: #order.code,
Quantity: 1,
Amount: {
currencyID: "EUR",
value: #order.total
},
ItemCategory: "Physical"
}],
PaymentAction: "Sale"
}]
}
})
# Make API call & get response
#express_checkout_response = #api.set_express_checkout(#set_express_checkout)
# Access Response
if #express_checkout_response.success?
#order.set_payment_token(#express_checkout_response.Token)
else
#express_checkout_response.Errors
end
def do_express_checkout
#do_express_checkout_payment = #api.build_do_express_checkout_payment({
DoExpressCheckoutPaymentRequestDetails: {
PaymentAction: "Sale",
Token: #order.payment_token,
PayerID: #order.payerID,
PaymentDetails: [{
OrderTotal: {
currencyID: "EUR",
value: #order.total
},
NotifyURL: PAYPAL_NOTIFY_URL
}]
}
})
# Make API call & get response
#do_express_checkout_payment_response = #api.do_express_checkout_payment(#do_express_checkout_payment)
# Access Response
if #do_express_checkout_payment_response.success?
details = #do_express_checkout_payment_response.DoExpressCheckoutPaymentResponseDetails
#order.set_payment_details(prepare_express_checkout_response(details))
else
errors = #do_express_checkout_payment_response.Errors # => Array
#order.save_payment_errors errors
end
end
end
The class is in /lib/modules and when loaded, the instance variables are nil
Started GET "/orders/1" for 127.0.0.1 at 2014-01-07 01:33:46 -0600
Processing by OrdersController#show as HTML
Parameters: {"id"=>"1"}
Order Load (0.2ms) SELECT "orders".* FROM "orders" WHERE "orders"."id" = ? LIMIT 1 [["id", "1"]]
Completed 500 Internal Server Error in 18ms
NoMethodError (undefined method total' for nil:NilClass):
lib/modules/paypal_interface.rb:25:in'
lib/modules/paypal_interface.rb:3:in <top (required)>'
app/controllers/orders_controller.rb:17:inshow'
schema.rb
ActiveRecord::Schema.define(:version => 20140107060318) do
create_table "orders", :force => true do |t|
t.text "code"
t.text "total"
t.text "payerID"
t.text "payment_token"
t.datetime "created_at", :null => false
t.datetime "updated_at", :null => false
end
end
I loaded a value of 10 into the form;and, i tried changing the total field to :decimal to no avail, but now I am stuck as the object does not pass to the module from the order controller.

Answer 1

If #question in PaypalInterface is nil, probably Order.find(params[:id]) doesn't find any.
In the show method:
#order = Order.find(params[:id])
#order is nil?
You could try with:
def show
if #order = Order.find(params[:id])
[...]
else
# Can't find order
end
end
I use Pry to debug this kind of errors, just require 'pry' then put binding.pry where you want to stop the code and open a console. An example is:
def show
#order = Order.find(params[:id])
require 'pry'
binding.pry # Go to the console and start debugging #order
[...]
end
ps. What you indicate as paypal_interface.rb is only a part of that file? Because that code seems wrong.