From 37cd432a9c1ff7975d34a92dacd95db4c9ef806d Mon Sep 17 00:00:00 2001
From: Jimmy Bogard <jimmy.bogard@gmail.com>
Date: Fri, 24 Nov 2023 18:02:50 -0600
Subject: [PATCH] Updating MediatR and switching to keyed services (#99)

* Updating MediatR and switching to keyed services

* Restoring the event types registration; removing unused HandlerTypes since it is using keyed services
---
 Directory.Packages.props                      |  4 ++--
 .../Abstractions/EventBusSubscriptionInfo.cs  |  2 --
 .../Extensions/EventBusBuilderExtensions.cs   | 21 +------------------
 src/EventBusRabbitMQ/RabbitMQEventBus.cs      | 10 +--------
 4 files changed, 4 insertions(+), 33 deletions(-)

diff --git a/Directory.Packages.props b/Directory.Packages.props
index 0de40a69..ede8fcdc 100644
--- a/Directory.Packages.props
+++ b/Directory.Packages.props
@@ -72,7 +72,7 @@
     <PackageVersion Include="Automapper" Version="12.0.1" />
     <PackageVersion Include="Dapper" Version="2.0.151" />
     <PackageVersion Include="FluentValidation.AspNetCore" Version="11.3.0" />
-    <PackageVersion Include="MediatR" Version="12.1.1" />
+    <PackageVersion Include="MediatR" Version="12.2.0" />
     <PackageVersion Include="Microsoft.Web.LibraryManager.Build" Version="2.1.175" />
     <PackageVersion Include="Polly" Version="8.2.0" />
     <PackageVersion Include="Swashbuckle.AspNetCore" Version="6.5.0" />
@@ -81,4 +81,4 @@
     <PackageVersion Include="xunit.runner.visualstudio" Version="2.5.1" />
     <PackageVersion Include="Yarp.ReverseProxy" Version="2.1.0-preview.1.23556.5" />
   </ItemGroup>
-</Project>
+</Project>
\ No newline at end of file
diff --git a/src/EventBus/Abstractions/EventBusSubscriptionInfo.cs b/src/EventBus/Abstractions/EventBusSubscriptionInfo.cs
index f00a284e..f18c47b1 100644
--- a/src/EventBus/Abstractions/EventBusSubscriptionInfo.cs
+++ b/src/EventBus/Abstractions/EventBusSubscriptionInfo.cs
@@ -7,8 +7,6 @@ public class EventBusSubscriptionInfo
 {
     public Dictionary<string, Type> EventTypes { get; } = [];
 
-    public Dictionary<Type, HashSet<Type>> HandlerTypes { get; } = [];
-
     public JsonSerializerOptions JsonSerializerOptions { get; } = new(DefaultSerializerOptions);
 
     internal static readonly JsonSerializerOptions DefaultSerializerOptions = new()
diff --git a/src/EventBus/Extensions/EventBusBuilderExtensions.cs b/src/EventBus/Extensions/EventBusBuilderExtensions.cs
index 1208ceee..5fea83f7 100644
--- a/src/EventBus/Extensions/EventBusBuilderExtensions.cs
+++ b/src/EventBus/Extensions/EventBusBuilderExtensions.cs
@@ -24,13 +24,7 @@ public static IEventBusBuilder ConfigureJsonOptions(this IEventBusBuilder eventB
         // Use keyed services to register multiple handlers for the same event type
         // the consumer can use IKeyedServiceProvider.GetKeyedService<IIntegrationEventHandler>(typeof(T)) to get all
         // handlers for the event type.
-
-        // MediatR assembly scanning breaks with keyed services see https://github.com/jbogard/MediatR/issues/942.
-        // eventBusBuilder.Services.AddKeyedTransient<IIntegrationEventHandler, TH>(typeof(T));
-
-        // Instead, we'll register the handler as transient and use the HandlerTypes on SubscriptionInfo to get all
-        // handlers for the event type.
-        eventBusBuilder.Services.AddTransient<TH>();
+        eventBusBuilder.Services.AddKeyedTransient<IIntegrationEventHandler, TH>(typeof(T));
 
         eventBusBuilder.Services.Configure<EventBusSubscriptionInfo>(o =>
         {
@@ -39,19 +33,6 @@ public static IEventBusBuilder ConfigureJsonOptions(this IEventBusBuilder eventB
 
             // This list will also be used to subscribe to events from the underlying message broker implementation.
             o.EventTypes[typeof(T).Name] = typeof(T);
-
-            // Handle the case where the same handler is registered twice for the same event type
-            if (o.HandlerTypes.TryGetValue(typeof(T), out var handlerTypes))
-            {
-                if (!handlerTypes.Add(typeof(TH)))
-                {
-                    throw new InvalidOperationException($"Handler Type {typeof(TH).GetGenericTypeName()} already registered for '{typeof(T)}'");
-                }
-            }
-            else
-            {
-                o.HandlerTypes[typeof(T)] = [typeof(TH)];
-            }
         });
 
         return eventBusBuilder;
diff --git a/src/EventBusRabbitMQ/RabbitMQEventBus.cs b/src/EventBusRabbitMQ/RabbitMQEventBus.cs
index ef8d255e..71580a2c 100644
--- a/src/EventBusRabbitMQ/RabbitMQEventBus.cs
+++ b/src/EventBusRabbitMQ/RabbitMQEventBus.cs
@@ -200,16 +200,8 @@ private async Task ProcessEvent(string eventName, string message)
         // REVIEW: This could be done in parallel
 
         // Get all the handlers using the event type as the key
-        // foreach (var handler in scope.ServiceProvider.GetKeyedServices<IIntegrationEventHandler>(eventType))
-
-        _subscriptionInfo.HandlerTypes.TryGetValue(eventType, out var handlerTypes);
-
-        handlerTypes ??= [];
-
-        foreach (var handlerType in handlerTypes)
+        foreach (var handler in scope.ServiceProvider.GetKeyedServices<IIntegrationEventHandler>(eventType))
         {
-            var handler = scope.ServiceProvider.GetRequiredService(handlerType) as IIntegrationEventHandler;
-
             // Deserialize the event
             var integrationEvent = DeserializeMessage(message, eventType);