Program.cs

using Microsoft.Extensions.Logging;
using System;
using System.Collections.Generic;
using System.Configuration;
using System.Net.Http;
using System.Threading.Tasks;

using ShippingRates.ShippingProviders;
using ShippingRates.ShippingProviders.FedEx;
using ShippingRates.ShippingProviders.Usps;
using ShippingRates;

namespace SampleApp
{
    class Program
    {
        static async Task Main()
        {
            var appSettings = ConfigurationManager.AppSettings;

            // You will need OAuth Client Id, Client Secret, and Account Number to use the UPS provider
            // More details: https://developer.ups.com/oauth-developer-guide?loc=en_US
            var upsClientId = appSettings["UPSClientId"];
            var upsClientSecret = appSettings["UPSClientSecret"];
            var upsAccountNumber = appSettings["UPSAccountNumber"];

            // You will need Client Id, Client Secret, and Account # to use the FedEx provider.
            var fedexClientId = appSettings["FedExClientId"];
            var fedexClientSecret = appSettings["FedExClientSecret"];
            var fedexAccountNumber = appSettings["FedExAccountNumber"];
            var fedexHubId = appSettings["FedExHubId"]; // 5531 is the hubId to use in FedEx's test environment
            var fedexUseProduction = Convert.ToBoolean(appSettings["FedExUseProduction"]);

            // You will need a Site ID and Password to use DHL provider.
            var dhlSiteId = appSettings["DHLSiteId"];
            var dhlPassword = appSettings["DHLPassword"];

            // Setup package and destination/origin addresses
            var packages = new List<Package>
            {
                new Package(12, 12, 12, 35, 150),
                new Package(4, 4, 6, 15, 250)
            };

            var origin = new Address("", "CT", "06405", "US");
            var destination = new Address("", "", "20852", "US"); // US Address
            //var origin = new Address("Amsterdam", "", "1043 AG", "NL"); // Netherlands Address
            //var destination = new Address("London", "", "SW1A 2AA", "GB"); // Great Britain Address
            //var destination = new Address("", "", "88888", "US"); // Wrong US Address
            //var destination = new Address("Domont", "", "95330", "FR"); // France Address
            //var destination = new Address("", "", "00907", "PR"); // Puerto Rico Address
            //var destination = new Address("", "", "L4W 1S2", "CA"); // Canada Address
            //var destination = new Address("", "", "SW1E 5JL", "GB"); // UK Address
            //var destination = new Address("", "", "1042 AG", "NL");   // Netherlands Address

            using (var loggerFactory = LoggerFactory.Create(builder =>
            {
                builder.AddConsole();
            }))
            {
                // Create RateManager
                var rateManager = new RateManager();

                using (var httpClient = new HttpClient())
                {
                    // Add desired providers
                    // UPS
                    var upsConfiguration = new UPSProviderConfiguration()
                    {
                        ClientId = upsClientId,
                        ClientSecret = upsClientSecret,
                        AccountNumber = upsAccountNumber,
                        UseProduction = false
                    };
                    var upsProviderLogger = loggerFactory.CreateLogger<UPSProvider>();
                    rateManager.AddProvider(new UPSProvider(upsConfiguration, httpClient, upsProviderLogger));

                    // FedEx
                    var fedExConfiguration = new FedExProviderConfiguration()
                    {
                        ClientId = fedexClientId,
                        ClientSecret = fedexClientSecret,
                        AccountNumber = fedexAccountNumber,
                        HubId = fedexHubId,
                        UseProduction = fedexUseProduction
                    };
                    var fedExProviderLogger = loggerFactory.CreateLogger<FedExProvider>();
                    rateManager.AddProvider(new FedExProvider(fedExConfiguration, httpClient, fedExProviderLogger));
                    rateManager.AddProvider(new FedExSmartPostProvider(fedExConfiguration, httpClient));

                    // USPS
                    var uspsProviderConfiguration = new UspsProviderConfiguration()
                    {
                        ClientId = appSettings["UspsClientId"],
                        ClientSecret = appSettings["UspsClientSecret"],
                        UseProduction = Convert.ToBoolean(appSettings["UspsUseProduction"])
                    };
                    var uspsProviderLogger = loggerFactory.CreateLogger<UspsProvider>();
                    rateManager.AddProvider(new UspsProvider(uspsProviderConfiguration, httpClient, uspsProviderLogger));

                    // DHL
                    var dhlConfiguration = new DHLProviderConfiguration(dhlSiteId, dhlPassword, useProduction: true).ExcludeServices(new char[] { 'C' });
                    rateManager.AddProvider(new DHLProvider(dhlConfiguration, httpClient));

                    // Call GetRates()
                    var shipment = await rateManager.GetRatesAsync(origin, destination, packages,
                        new ShipmentOptions()
                        {
                            SaturdayDelivery = true
                        });

                    // Iterate through the rates returned
                    foreach (var rate in shipment.Rates)
                    {
                        Console.WriteLine(rate);
                    }

                    // Iterate through the errors returned
                    if (shipment.Errors.Count > 0)
                    {
                        Console.WriteLine("Errors:");
                        foreach (var error in shipment.Errors)
                        {
                            Console.WriteLine(error.Number);
                            Console.WriteLine(error.Source);
                            Console.WriteLine(error.Description);
                        }
                    }

                    // Iterate through the internal errors
                    if (shipment.InternalErrors.Count > 0)
                    {
                        Console.WriteLine("Internal Errors:");
                        foreach (var error in shipment.InternalErrors)
                        {
                            Console.WriteLine(error);
                        }
                    }
                }

                Console.WriteLine("Done!");
            }
        }
    }
}