Slap-on-top rest services

Global.asax.cs

using System;
using System.Reflection;
using System.Web;

namespace Host
{
    public class Global : HttpApplication
    {
		protected void Application_BeginRequest (object sender, EventArgs e) {
			if (HttpContext.Current.Request.RawUrl.StartsWith(RestHandler.RestPrefix)) {
				Server.Transfer(new RestHandler(), true);
			}
		}
    }
}

IRestResponder.cs

using System.Collections.Specialized;

namespace Rest {
	public interface IRestResponder {
		string ServiceName { get; }
		object Handle (NameValueCollection parameters);
	}
}

MySampleResponder.cs

using System;
using System.Collections.Specialized;
using MediaFreedom.Content.Contracts;
using MediaFreedom.Content.Delivery.Contracts;
using MediaFreedom.Delivery.Application;
using StructureMap;

namespace Rest {
	/// <summary>
	/// Sample call --> http://example.com/api/v1/sample?id=myref
	/// </summary>
	public class MediaGet : IRestResponder{
		public string ServiceName {
			get { return "sample"; }
		}

		public object Handle(NameValueCollection parameters) {
			var id = Guid.Parse(parameters["id"]);
			
			// ... do a bunch of work here ...
			
			return new {
				sampleValue = "hello, world",
				yourId = id.ToString()
			};
		}
	}
}

RestHandler.cs

using System.Web;
using System.Web.Script.Serialization;
using System.Web.UI;
using Rest;

namespace Host {
	public class RestHandler : Page, IHttpHandler { // 'Page' required for Server.Transfer in Global.asax
		public const string RestPrefix = "/api/v1/";

		new public void ProcessRequest (HttpContext context) {
			var service = context.Request.Url.AbsolutePath.Replace(RestPrefix, "");

			var obj = GetResponseObject(context, service);
			if (obj == null) return;

			context.Response.AddHeader("Content-Disposition", "inline;filename=\"" + service + ".json\"");
			context.Response.ContentType = "application/json";

			var js = new JavaScriptSerializer();
			context.Response.Write(js.Serialize(obj));
		}

		object GetResponseObject (HttpContext context, string service) {
			foreach (var responder in RestResponders.All()) {
				if (service == responder.ServiceName) {
					return responder.Handle(context.Request.Params);
				}
			}

			context.Response.StatusCode = 404;
			context.Response.Flush();
			context.Response.End();
			return null;
		}
	}
}

RestResponders.cs

using System;
using System.Collections.Generic;
using System.Collections.Specialized;
using System.Net;
using Rest.Sample;

namespace Rest {
	public class RestResponders {
		public static IEnumerable<IRestResponder> All () {
			return new IRestResponder[] {
				new MySampleResponder(),
				new OtherResponder()
				//...etc...
				// can do this with IoC instead
			};
		}
	}
}