Sinatraでwebpayを使った課金処理

app.rb

require 'bundler'
Bundler.require

webpay = WebPay.new('xxxxxx')
WEBPAY_PUBLIC_KEY = 'xxxxxx')
MAMORIO_PRICE = 3500

set :slim, format: :html5

get '/' do
  slim :index
end

post '/purchase' do
  begin
    @charge = webpay.charge.create(currency: 'jpy', amount: XXXXX_PRICE, card: params['webpay-token'])
    slim :purchased
  rescue => e
    redirect to('/')
  end
end