nancy throttling

NancyThrottling.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; }
    }
}