Basic throttling in Nancy

gistfile1.cs

    using System;
    using System.Runtime.Caching;
    using Bootstrapper;

    public class Home : NancyModule
    {
        public Home()
        {
            Get["/"] = parameters => {
                return "Hi";
            };
        }
    }

    public class ThrottlingHooks : IApplicationStartup
    {
        private readonly IThrottleCache cache;

        public ThrottlingHooks(IThrottleCache cache)
        {
            this.cache = cache;
        }

        public void Initialize(IPipelines pipelines)
        {
            pipelines.BeforeRequest.AddItemToStartOfPipeline(ctx => {
                if (this.cache.IsRateExceeded(ctx.Request.UserHostAddress))
                {
                    return HttpStatusCode.TooManyRequests;
                }
                
                return null;
            });

            pipelines.AfterRequest.AddItemToStartOfPipeline(ctx => {
                this.cache.Register(ctx.Request.UserHostAddress);        
            });
        }
    }

    public interface IThrottleCache
    {
        bool IsRateExceeded(string host);

        void Register(string host);
    }

    public class InMemoryThrottleCache : IThrottleCache
    {
        private readonly MemoryCache cache;

        public InMemoryThrottleCache()
        {
            this.cache = new MemoryCache("ThrottlingCache");
        }

        public bool IsRateExceeded(string host)
        {
            if (!this.cache.Contains(host))
            {
                return false;
            }

            return ((ThrottleToken) this.cache[host]).Count > 10;
        }

        public void Register(string host)
        {
            if (!this.cache.Contains(host))
            {
                this.cache.Add(host, new ThrottleToken(), DateTimeOffset.Now.AddMinutes(1));
            }

            var token =
                this.cache.Get(host) as ThrottleToken;

            token.Count++;
        }

        private class ThrottleToken
        {
            public int Count { get; set; }
        }
    }