PayPal REST API SDK Payment Serice example

gistfile1.cs

namespace Application.Services
{
    using System.Collections.Generic;
    using System.Configuration;
    using System.Globalization;
    using System.Linq;
    using System.Web;
    using System.Web.Mvc;

    using global::PayPal;
    using global::PayPal.Api.Payments;

    using Application.Model;

    public class PaymentService : IPaymentService
    {
        private OAuthTokenCredential _authToken;
        private APIContext _api;

        public Payment CreatePayment(Order order, string cancelUrl, string returnUrl)
        {
            var amount = this.CreateAmount(order);

            var payment = new Payment
                          {
                              transactions = new List<Transaction> 
                                             { 
                                                new Transaction
                                                {
                                                    amount = amount,
                                                    description = "Purchase From Application"
                                                } 
                                             },
                              intent = "sale",
                              payer = new Payer { payment_method = "paypal" },
                              redirect_urls = new RedirectUrls
                                              {
                                                  cancel_url = cancelUrl,
                                                  return_url = returnUrl
                                              }
                          };

            payment = payment.Create(this.Api);

            return payment;
        }

        public Payment ConfirmPayment(string token, string payerId, Order order)
        {
            var paymentExecution = new PaymentExecution
                                   {
                                       payer_id = payerId
                                   };

            var payment = new Payment { id = token };

            return payment.Execute(this.Api, paymentExecution);
        }

        private Amount CreateAmount(Order order)
        {
            var details = new Details
            {
                subtotal = order.SubTotal.ToString("0.00", CultureInfo.CurrentCulture),
                shipping = order.Shipping.ToString("0.00", CultureInfo.CurrentCulture),
                tax = order.Tax.ToString("0.00", CultureInfo.CurrentCulture),
                fee = order.Fees.ToString("0.00", CultureInfo.CurrentCulture)
            };

            var total = order.SubTotal + order.Shipping + order.Tax + order.Fees;

            var amount = new Amount
            {
                currency = "USD",
                details = details,
                total = total.ToString("0.00", CultureInfo.CurrentCulture)
            };

            return amount;
        }

        private OAuthTokenCredential ApiAccessToken
        {
            get
            {
                if (this._authToken != null)
                {
                    return this._authToken;
                }

                var clientId = ConfigurationManager.AppSettings["clientId"];
                var secretToken = ConfigurationManager.AppSettings["secretToken"];
                var config = new Dictionary<string, string> { { "mode", "sandbox" } };

                this._authToken = new OAuthTokenCredential(clientId, secretToken, config);

                return this._authToken;
            }
        }

        private APIContext Api
        {
            get
            {
                return this._api ?? (this._api = new APIContext(this.ApiAccessToken.GetAccessToken()));
            }
        }
    }
}