Replace DomainEventDispatcher with MediatR (ardalis#120)

src/CleanArchitecture.Core/CleanArchitecture.Core.csproj

@@ -7,6 +7,7 @@
 
   <ItemGroup>
     <PackageReference Include="Ardalis.GuardClauses" Version="1.4.2" />
+    <PackageReference Include="MediatR" Version="8.0.1" />
   </ItemGroup>
 
   <ItemGroup>

src/CleanArchitecture.Core/Handlers/ItemCompletedEmailNotificationHandler.cs

@@ -1,12 +1,13 @@
-using System.Threading.Tasks;
+using System.Threading;
+using System.Threading.Tasks;
 using Ardalis.GuardClauses;
 using CleanArchitecture.Core.Events;
 using CleanArchitecture.Core.Interfaces;
-using CleanArchitecture.SharedKernel.Interfaces;
+using MediatR;
 
 namespace CleanArchitecture.Core.Services
 {
-    public class ItemCompletedEmailNotificationHandler : IHandle<ToDoItemCompletedEvent>
+    public class ItemCompletedEmailNotificationHandler : INotificationHandler<ToDoItemCompletedEvent>
     {
         private readonly IEmailSender _emailSender;
 
@@ -17,7 +18,7 @@ public ItemCompletedEmailNotificationHandler(IEmailSender emailSender)
 
         // configure a test email server to demo this works
         // https://ardalis.com/configuring-a-local-test-email-server
-        public async Task Handle(ToDoItemCompletedEvent domainEvent)
+        public async Task Handle(ToDoItemCompletedEvent domainEvent, CancellationToken cancellationToken)
         {
             Guard.Against.Null(domainEvent, nameof(domainEvent));
 

src/CleanArchitecture.Infrastructure/Data/AppDbContext.cs

@@ -8,21 +8,22 @@
 using Ardalis.EFCore.Extensions;
 using System.Reflection;
 using JetBrains.Annotations;
+using MediatR;
 
 namespace CleanArchitecture.Infrastructure.Data
 {
     public class AppDbContext : DbContext
     {
-        private readonly IDomainEventDispatcher _dispatcher;
+        private readonly IMediator _mediator;
 
         //public AppDbContext(DbContextOptions options) : base(options)
         //{
         //}
 
-        public AppDbContext(DbContextOptions<AppDbContext> options, IDomainEventDispatcher dispatcher)
+        public AppDbContext(DbContextOptions<AppDbContext> options, IMediator mediator)
             : base(options)
         {
-            _dispatcher = dispatcher;
+            _mediator = mediator;
         }
 
         public DbSet<ToDoItem> ToDoItems { get; set; }
@@ -42,7 +43,7 @@ protected override void OnModelCreating(ModelBuilder modelBuilder)
             int result = await base.SaveChangesAsync(cancellationToken).ConfigureAwait(false);
 
             // ignore events if no dispatcher provided
-            if (_dispatcher == null) return result;
+            if (_mediator == null) return result;
 
             // dispatch events only if save was successful
             var entitiesWithEvents = ChangeTracker.Entries<BaseEntity>()
@@ -56,7 +57,7 @@ protected override void OnModelCreating(ModelBuilder modelBuilder)
                 entity.Events.Clear();
                 foreach (var domainEvent in events)
                 {
-                    await _dispatcher.Dispatch(domainEvent).ConfigureAwait(false);
+                    await _mediator.Publish(domainEvent).ConfigureAwait(false);
                 }
             }
 

src/CleanArchitecture.Infrastructure/DefaultInfrastructureModule.cs

@@ -1,9 +1,11 @@
 using Autofac;
 using CleanArchitecture.Core;
 using CleanArchitecture.Core.Interfaces;
+using CleanArchitecture.Core.Services;
 using CleanArchitecture.Infrastructure.Data;
-using CleanArchitecture.Infrastructure.DomainEvents;
 using CleanArchitecture.SharedKernel.Interfaces;
+using MediatR;
+using MediatR.Pipeline;
 using System.Collections.Generic;
 using System.Reflection;
 using Module = Autofac.Module;
@@ -43,13 +45,35 @@ protected override void Load(ContainerBuilder builder)
 
         private void RegisterCommonDependencies(ContainerBuilder builder)
         {
-            builder.RegisterType<DomainEventDispatcher>().As<IDomainEventDispatcher>()
-                .InstancePerLifetimeScope();
             builder.RegisterType<EfRepository>().As<IRepository>()
                 .InstancePerLifetimeScope();
 
-            builder.RegisterAssemblyTypes(_assemblies.ToArray())
-                .AsClosedTypesOf(typeof(IHandle<>));
+            builder
+                .RegisterType<Mediator>()
+                .As<IMediator>()
+                .InstancePerLifetimeScope();
+
+            builder.Register<ServiceFactory>(context =>
+            {
+                var c = context.Resolve<IComponentContext>();
+                return t => c.Resolve(t);
+            });
+
+            var mediatrOpenTypes = new[]
+            {
+                typeof(IRequestHandler<,>),
+                typeof(IRequestExceptionHandler<,,>),
+                typeof(IRequestExceptionAction<,>),
+                typeof(INotificationHandler<>),
+            };
+
+            foreach (var mediatrOpenType in mediatrOpenTypes)
+            {
+                builder
+                .RegisterAssemblyTypes(_assemblies.ToArray())
+                .AsClosedTypesOf(mediatrOpenType)
+                .AsImplementedInterfaces();
+            }
 
             builder.RegisterType<EmailSender>().As<IEmailSender>()
                 .InstancePerLifetimeScope();

src/CleanArchitecture.SharedKernel/BaseDomainEvent.cs

@@ -1,8 +1,9 @@
-using System;
+using MediatR;
+using System;
 
 namespace CleanArchitecture.SharedKernel
 {
-    public abstract class BaseDomainEvent
+    public abstract class BaseDomainEvent : INotification
     {
         public DateTime DateOccurred { get; protected set; } = DateTime.UtcNow;
     }

src/CleanArchitecture.SharedKernel/CleanArchitecture.SharedKernel.csproj

@@ -4,4 +4,8 @@
     <TargetFramework>netstandard2.0</TargetFramework>
   </PropertyGroup>
 
+  <ItemGroup>
+    <PackageReference Include="MediatR" Version="8.0.1" />
+  </ItemGroup>
+
 </Project>

src/CleanArchitecture.Web/CleanArchitecture.Web.csproj

@@ -11,6 +11,7 @@
   <ItemGroup>
     <PackageReference Include="Ardalis.ApiEndpoints" Version="0.9.4" />
     <PackageReference Include="Ardalis.ListStartupServices" Version="1.1.3" />
+    <PackageReference Include="MediatR" Version="8.0.1" />
     <PackageReference Include="Microsoft.AspNetCore.Mvc.NewtonsoftJson" Version="3.1.3" />
     <PackageReference Include="Microsoft.EntityFrameworkCore.Tools" PrivateAssets="all" Version="3.1.3" />
     <PackageReference Include="Microsoft.VisualStudio.Web.CodeGeneration.Design" PrivateAssets="All" Version="3.1.2" />

src/CleanArchitecture.Web/web.config

@@ -7,9 +7,10 @@
     <handlers>
       <add name="aspNetCore" path="*" verb="*" modules="AspNetCoreModuleV2" resourceType="Unspecified" />
     </handlers>
-    <aspNetCore processPath="%LAUNCHER_PATH%" arguments="%LAUNCHER_ARGS%" stdoutLogEnabled="false" stdoutLogFile=".\logs\stdout" forwardWindowsAuthToken="false" startupTimeLimit="3600" requestTimeout="23:00:00" hostingModel="InProcess">
+    <aspNetCore processPath="%LAUNCHER_PATH%" stdoutLogEnabled="false" stdoutLogFile=".\logs\stdout" forwardWindowsAuthToken="false" startupTimeLimit="3600" requestTimeout="23:00:00" hostingModel="InProcess">
       <environmentVariables>
         <environmentVariable name="ASPNETCORE_ENVIRONMENT" value="Development" />
+        <environmentVariable name="COMPLUS_ForceENC" value="1" />
       </environmentVariables>
     </aspNetCore>
   </system.webServer>

tests/CleanArchitecture.FunctionalTests/CustomWebApplicationFactory.cs

@@ -10,6 +10,7 @@
 using System;
 using Microsoft.AspNetCore.TestHost;
 using System.Linq;
+using MediatR;
 
 namespace CleanArchitecture.FunctionalTests
 {
@@ -50,7 +51,7 @@ protected override void ConfigureWebHost(IWebHostBuilder builder)
                 //    options.UseInternalServiceProvider(serviceProvider);
                 //});
 
-                services.AddScoped<IDomainEventDispatcher, NoOpDomainEventDispatcher>();
+                services.AddScoped<IMediator, NoOpMediator>();
 
                 // Build the service provider.
                 var sp = services.BuildServiceProvider();

tests/CleanArchitecture.IntegrationTests/Data/BaseEfRepoTestFixture.cs

@@ -3,6 +3,7 @@
 using Microsoft.EntityFrameworkCore;
 using Microsoft.Extensions.DependencyInjection;
 using Moq;
+using MediatR;
 
 namespace CleanArchitecture.IntegrationTests.Data
 {
@@ -30,9 +31,9 @@ protected static DbContextOptions<AppDbContext> CreateNewContextOptions()
         protected EfRepository GetRepository()
         {
             var options = CreateNewContextOptions();
-            var mockDispatcher = new Mock<IDomainEventDispatcher>();
+            var mockMediator = new Mock<IMediator>();
 
-            _dbContext = new AppDbContext(options, mockDispatcher.Object);
+            _dbContext = new AppDbContext(options, mockMediator.Object);
             return new EfRepository(_dbContext);
         }
     }

tests/CleanArchitecture.UnitTests/Core/Handlers/ItemCompletedEmailNotificationHandlerHandle.cs

@@ -4,6 +4,7 @@
 using CleanArchitecture.Core.Services;
 using Moq;
 using System;
+using System.Threading;
 using System.Threading.Tasks;
 using Xunit;
 
@@ -23,13 +24,13 @@ public ItemCompletedEmailNotificationHandlerHandle()
         [Fact]
         public async Task ThrowsExceptionGivenNullEventArgument()
         {
-            Exception ex = await Assert.ThrowsAsync<ArgumentNullException>(() => _handler.Handle(null));
+            Exception ex = await Assert.ThrowsAsync<ArgumentNullException>(() => _handler.Handle(null, CancellationToken.None));
         }
 
         [Fact]
         public async Task SendsEmailGivenEventInstance()
         {
-            await _handler.Handle(new ToDoItemCompletedEvent(new ToDoItem()));
+            await _handler.Handle(new ToDoItemCompletedEvent(new ToDoItem()), CancellationToken.None);
 
             _emailSenderMock.Verify(sender => sender.SendEmailAsync(It.IsAny<string>(), It.IsAny<string>(), It.IsAny<string>(), It.IsAny<string>()), Times.Once);
         }