How to use a RequestBinder in ServiceStack (v4) to convert a complex JSON object into a request.

program.cs

using System;
using System.Linq;
using ServiceStack.Text;
using System.Collections.Generic;
using System.Runtime.Serialization;
using ServiceStack;
using ServiceStack.Web;
using System.Net;

namespace JsonTest
{
	class MainClass
	{
		public static void Main()
		{
			// Very basic console host
			var appHost = new AppHost(500);
			appHost.Init();
			appHost.Start("http://*:9000/");
			Console.ReadKey();
		}
	}

	public class AppHost : AppHostHttpListenerPoolBase
	{
		public AppHost(int poolSize) : base("Merchant Service", poolSize, typeof(MerchantsService).Assembly) {}

		public override void Configure(Funq.Container container)
		{
			Func<IRequest, object> merchantsRequestBinder = delegate(IRequest request) {
				var json = WebUtility.HtmlDecode( request.GetRawBody() );
				return new MerchantsRequest { MainMerchants = JsonSerializer.DeserializeFromString<Dictionary<int, Merchant>>(json) };
			};

			RequestBinders.Add(typeof(MerchantsRequest), merchantsRequestBinder);

			Config = new HostConfig {
				DebugMode = true,
			};
		}

	}

	[Route("/Merchants", "POST")]
	public class MerchantsRequest
	{
		public Dictionary<int, Merchant> MainMerchants { get; set; }
	}

	public class MerchantsService : Service
	{
		public void Post(MerchantsRequest request)
		{
			var merchant39 = request.MainMerchants.First(p=>p.Key == 39).Value;
			Console.WriteLine("Name: {0}\nImage: {1}\nProduct Count: {2}", merchant39.name, merchant39.image88x31, merchant39.products.Count);

			var merchant40 = request.MainMerchants.First(p=>p.Key == 40).Value;
			Console.WriteLine("Name: {0}\nImage: {1}\nProduct Count: {2}", merchant40.name, merchant40.image88x31, merchant40.products.Count);
		}
	}

	public class Product
	{
		public string status { get; set; }
		public string type { get; set; }
		public string code { get; set; }
		public string end_date { get; set; }
		public string title { get; set; }
		public string url { get; set; }
		public string text { get; set; }
		public string long_title { get; set; }
	}


	/*
	 * Use DataMember to map the keys starting with numbers to an alternative c# compatible name.
	 * Unfortunately this requires properties to opt in to the data contract.
	 */
	[DataContract]
	public class Merchant
	{
		[DataMember]
		public string category { get; set; }

		[DataMember]
		public List<string> country_whitelist { get; set; }

		[DataMember]
		public string name { get; set; }

		[DataMember]
		public List<string> url_blacklist { get; set; }

		[DataMember]
		public List<string> country_blacklist { get; set; }

		[DataMember]
		public List<string> url_whitelist { get; set; }

		[DataMember]
		public Dictionary<int, Product>  products { get; set; }

		[DataMember]
		public string sub_category { get; set; }

		// This maps the 88x31 key to a c# appropriate name
		[DataMember(Name = "88x31")]
		public string image88x31 { get; set; }
	}
}