vgquotes/Src/VideoGameQuotes.Web/Configuration/UpdateSearchIndexCallHandler.cs

using System;
using System.Linq.Expressions;
using System.Reflection;
using Microsoft.Practices.Unity;
using Microsoft.Practices.Unity.InterceptionExtension;
using Portoa.Persistence;
using Portoa.Search;
using VideoGameQuotes.Api;

namespace VideoGameQuotes.Web.Configuration {

	public class UpdateSearchIndex : UnityContainerExtension {
		protected override void Initialize() {
			Container
				.Configure<Interception>()
				.AddPolicy("UpdateSearchIndexPolicy")
				.AddCallHandler<UpdateSearchIndexCallHandler>()
				.AddMatchingRule<QuoteUpdatedMatchingRule>();
		}
	}

	public class QuoteUpdatedMatchingRule : IMatchingRule {
		private static readonly MethodBase saveMethod = typeof(IRepository<Quote, int>).GetMethod("Save", new[] { typeof(Quote) });

		public bool Matches(MethodBase member) {
			return member == saveMethod;
		}
	}

	public class UpdateSearchIndexCallHandler : ICallHandler {
		private readonly IUnityContainer container;

		/// <remarks>
		/// Can't inject ISearchIndexBuilder because it causes an infinite loop
		/// while trying to instantiate the call handler. So we do a later resolve
		/// on the index builder so that this shit fucking works.
		/// </remarks>
		public UpdateSearchIndexCallHandler(IUnityContainer container) {
			this.container = container;
		}

		public IMethodReturn Invoke(IMethodInvocation input, GetNextHandlerDelegate getNext) {
			var returnValue = getNext()(input, getNext);
			if (returnValue.Exception != null) {
				//if the update failed then just return
				return returnValue;
			}

			var quote = returnValue.ReturnValue as Quote;
			if (quote == null) {
				return returnValue;
			}

			container.Resolve<ISearchIndexBuilder<Quote>>().UpdateIndex(quote);

			return returnValue;
		}

		public int Order { get; set; }
	}
}