Program.cs

// https://groups.google.com/forum/#!topic/jayrock/WbWpudBQWD8

using System;
using System.Collections;
using System.Collections.Generic;
using Jayrock.Json;
using Jayrock.JsonRpc;
using Jayrock.JsonRpc.Web;
using Jayrock.Services;

static class Program
{
    static void Main()
    {
        JsonRpcDispatcherFactory.Current = s => new JsonRpcDispatcher(s);
        var service = new MyService();
        var dispatcher = JsonRpcDispatcherFactory.CreateDispatcher(service);
        Console.WriteLine(dispatcher.Process("{ id: 1, method: cities }"));
    }

    class MyService : JsonRpcHandler
    {
        [JsonRpcMethod(Idempotent = true)]
        public IEnumerable<string> Cities()
        {
            return new[] { "London", "Zurich", "Paris", "New York" };
        }
    }

    class JsonRpcDispatcher : Jayrock.JsonRpc.JsonRpcDispatcher
    {
        public JsonRpcDispatcher(IService service) : base(service) {}

        protected override void WriteResponse(IDictionary response, JsonWriter output)
        {
            // TODO handle case where response is an error
            JsonExporter(response["result"], output);
        }
    }
}