code example

LifetimeScopeCommandHandlerDecorator.cs

using Autofac;
using MediatR;
using Microsoft.Owin;
using System.Diagnostics;
using System.Threading.Tasks;

namespace SB.PortAdapter.MediatR
{
    /// <summary>
    ///  Wraps inner Command Handler in Autofac Lifetime scope named LifeTimeScopeKeys.PerHandlerKey
    /// </summary>
    /// <typeparam name="TRequest"></typeparam>
    /// <typeparam name="TResponse"></typeparam>
    public class LifetimeScopeCommandHandlerDecorator<TRequest, TResponse> :
        IAsyncRequestHandler<TRequest, TResponse> where TRequest : class, IAsyncRequest<TResponse>
    {
        private readonly ILifetimeScope _scope;

        /// <summary>
        /// Const Name of Scope that dependencies can Match using PerMatchingLifeTimeScope(LifetimeScopeCommandHandlerDecorator.ScopeName)
        /// </summary>
        public const string ScopeName = LifeTimeScopeKeys.PerHandlerKey;

        /// <summary>
        /// constructor
        /// </summary>
        /// <param name="scope"></param>
        public LifetimeScopeCommandHandlerDecorator(/* IOwinContext context */ ILifetimeScope scope )
        {
            //_owinContext = context;
            _scope = scope;
        }

        public async Task<TResponse> Handle( TRequest request )
        {
            var owinContext = _scope.Resolve<IOwinContext>();

            Debug.WriteLine( owinContext.GetType().FullName );

            TResponse response;
            using ( var perHandlerScope = _scope.BeginLifetimeScope( LifeTimeScopeKeys.PerHandlerKey ) )
            {
                var decoratedHandler =
                    perHandlerScope.ResolveKeyed<IAsyncRequestHandler<TRequest, TResponse>>( "IAsyncRequestHandlerKey" );
                response = await decoratedHandler.Handle( request );
            }

            return response;
        }
    }
}