Removing extraneous interfaces and classes for exceptions

samples/MediatR.Examples.Lamar/Program.cs

@@ -25,7 +25,7 @@ private static IMediator BuildMediator(WrappingWriter writer)
                 scanner.AssemblyContainingType<Ping>();
                 scanner.ConnectImplementationsToTypesClosing(typeof(IRequestHandler<,>));
                 scanner.ConnectImplementationsToTypesClosing(typeof(INotificationHandler<>));
-                scanner.ConnectImplementationsToTypesClosing(typeof(IRequestExceptionAction<>));
+                scanner.ConnectImplementationsToTypesClosing(typeof(IRequestExceptionAction<,>));
                 scanner.ConnectImplementationsToTypesClosing(typeof(IRequestExceptionHandler<,,>));
             });
 

samples/MediatR.Examples/ExceptionHandler/ExceptionsHandlers.cs

@@ -6,13 +6,13 @@
 
 namespace MediatR.Examples.ExceptionHandler;
 
-public class CommonExceptionHandler : AsyncRequestExceptionHandler<PingResource, Pong>
+public class CommonExceptionHandler : IRequestExceptionHandler<PingResource, Pong, Exception>
 {
     private readonly TextWriter _writer;
 
     public CommonExceptionHandler(TextWriter writer) => _writer = writer;
 
-    protected override async Task Handle(PingResource request,
+    public async Task Handle(PingResource request,
         Exception exception,
         RequestExceptionHandlerState<Pong> state,
         CancellationToken cancellationToken)

samples/MediatR.Examples/ExceptionHandler/ExceptionsHandlersOverrides.cs

@@ -6,13 +6,13 @@
 
 namespace MediatR.Examples.ExceptionHandler.Overrides;
 
-public class CommonExceptionHandler : AsyncRequestExceptionHandler<PingResourceTimeout, Pong>
+public class CommonExceptionHandler : IRequestExceptionHandler<PingResourceTimeout, Pong, Exception>
 {
     private readonly TextWriter _writer;
 
     public CommonExceptionHandler(TextWriter writer) => _writer = writer;
 
-    protected override async Task Handle(PingResourceTimeout request,
+    public async Task Handle(PingResourceTimeout request,
         Exception exception,
         RequestExceptionHandlerState<Pong> state,
         CancellationToken cancellationToken)

samples/MediatR.Examples/ExceptionHandler/LogExceptionAction.cs

@@ -6,7 +6,7 @@
 
 namespace MediatR.Examples.ExceptionHandler;
 
-public class LogExceptionAction : IRequestExceptionAction<Ping>
+public class LogExceptionAction : IRequestExceptionAction<Ping, Exception>
 {
     private readonly TextWriter _writer;
 

src/MediatR/Pipeline/IRequestExceptionAction.cs

@@ -22,78 +22,3 @@ public interface IRequestExceptionAction<in TRequest, in TException>
     /// <returns>An awaitable task</returns>
     Task Execute(TRequest request, TException exception, CancellationToken cancellationToken);
 }
-
-/// <summary>
-/// Defines the base exception action for a request.
-///     You do not need to register this interface explicitly
-///     with a container as it inherits from the base
-///     <see cref="IRequestExceptionAction{TRequest, TException}" /> interface.
-/// </summary>
-/// <typeparam name="TRequest">The type of failed request</typeparam>
-public interface IRequestExceptionAction<in TRequest> : IRequestExceptionAction<TRequest, Exception>
-    where TRequest : notnull
-{
-}
-
-/// <summary>
-/// Wrapper class that asynchronously performs an action on a request for base exception
-/// </summary>
-/// <typeparam name="TRequest">The type of failed request</typeparam>
-public abstract class AsyncRequestExceptionAction<TRequest> : IRequestExceptionAction<TRequest>
-    where TRequest : IRequest
-{
-    async Task IRequestExceptionAction<TRequest, Exception>.Execute(TRequest request, Exception exception, CancellationToken cancellationToken) 
-        => await Execute(request, exception, cancellationToken).ConfigureAwait(false);
-
-    /// <summary>
-    /// Override in a derived class for the action logic
-    /// </summary>
-    /// <param name="request">Failed request</param>
-    /// <param name="exception">Original exception from request handler</param>
-    /// <param name="cancellationToken">Cancellation token</param>
-    protected abstract Task Execute(TRequest request, Exception exception, CancellationToken cancellationToken);
-}
-
-/// <summary>
-/// Wrapper class that synchronously performs an action on a request for specific exception
-/// </summary>
-/// <typeparam name="TRequest">Request type</typeparam>
-/// <typeparam name="TException">Exception type</typeparam>
-public abstract class RequestExceptionAction<TRequest, TException> : IRequestExceptionAction<TRequest, TException>
-    where TRequest : notnull
-    where TException : Exception
-{
-    Task IRequestExceptionAction<TRequest, TException>.Execute(TRequest request, TException exception, CancellationToken cancellationToken)
-    {
-        Execute(request, exception);
-        return Task.CompletedTask;
-    }
-
-    /// <summary>
-    /// Override in a derived class for the action logic
-    /// </summary>
-    /// <param name="request">Failed request</param>
-    /// <param name="exception">Original exception from request handler</param>
-    protected abstract void Execute(TRequest request, TException exception);
-}
-
-/// <summary>
-/// Wrapper class that synchronously performs an action on a request for base exception
-/// </summary>
-/// <typeparam name="TRequest">Request type</typeparam>
-public abstract class RequestExceptionAction<TRequest> : IRequestExceptionAction<TRequest>
-    where TRequest : notnull
-{
-    Task IRequestExceptionAction<TRequest, Exception>.Execute(TRequest request, Exception exception, CancellationToken cancellationToken)
-    {
-        Execute(request, exception);
-        return Task.CompletedTask;
-    }
-
-    /// <summary>
-    /// Override in a derived class for the action logic
-    /// </summary>
-    /// <param name="request">Failed request</param>
-    /// <param name="exception">Original exception from request handler</param>
-    protected abstract void Execute(TRequest request, Exception exception);
-}

src/MediatR/Pipeline/IRequestExceptionHandler.cs

@@ -24,84 +24,3 @@ public interface IRequestExceptionHandler<in TRequest, TResponse, in TException>
     /// <returns>An awaitable task</returns>
     Task Handle(TRequest request, TException exception, RequestExceptionHandlerState<TResponse> state, CancellationToken cancellationToken);
 }
-
-/// <summary>
-/// Defines the base exception handler for a request and response
-/// </summary>
-/// <typeparam name="TRequest">Request type</typeparam>
-/// <typeparam name="TResponse">Response type</typeparam>
-public interface IRequestExceptionHandler<in TRequest, TResponse> : IRequestExceptionHandler<TRequest, TResponse, Exception>
-    where TRequest : notnull
-{
-}
-
-/// <summary>
-/// Wrapper class that asynchronously handles a base exception from request
-/// </summary>
-/// <typeparam name="TRequest">Request type</typeparam>
-/// <typeparam name="TResponse">Response type</typeparam>
-public abstract class AsyncRequestExceptionHandler<TRequest, TResponse> : IRequestExceptionHandler<TRequest, TResponse>
-    where TRequest : notnull
-{
-    async Task IRequestExceptionHandler<TRequest, TResponse, Exception>.Handle(TRequest request, Exception exception, RequestExceptionHandlerState<TResponse> state, CancellationToken cancellationToken)
-    {
-        await Handle(request, exception, state, cancellationToken).ConfigureAwait(false);
-    }
-
-    /// <summary>
-    /// Override in a derived class for the handler logic
-    /// </summary>
-    /// <param name="request">Failed request</param>
-    /// <param name="exception">The thrown exception</param>
-    /// <param name="state">The current state of handling the exception</param>
-    /// <param name="cancellationToken">Cancellation token</param>
-    protected abstract Task Handle(TRequest request, Exception exception, RequestExceptionHandlerState<TResponse> state, CancellationToken cancellationToken);
-}
-
-/// <summary>
-/// Wrapper class that synchronously handles an exception from request
-/// </summary>
-/// <typeparam name="TRequest">Request type</typeparam>
-/// <typeparam name="TResponse">Response type</typeparam>
-/// <typeparam name="TException">Exception type</typeparam>
-public abstract class RequestExceptionHandler<TRequest, TResponse, TException> : IRequestExceptionHandler<TRequest, TResponse, TException>
-    where TRequest : notnull
-    where TException : Exception
-{
-    Task IRequestExceptionHandler<TRequest, TResponse, TException>.Handle(TRequest request, TException exception, RequestExceptionHandlerState<TResponse> state, CancellationToken cancellationToken)
-    {
-        Handle(request, exception, state);
-        return Task.CompletedTask;
-    }
-
-    /// <summary>
-    /// Override in a derived class for the handler logic
-    /// </summary>
-    /// <param name="request">Failed request</param>
-    /// <param name="exception">The thrown exception</param>
-    /// <param name="state">The current state of handling the exception</param>
-    protected abstract void Handle(TRequest request, TException exception, RequestExceptionHandlerState<TResponse> state);
-}
-
-/// <summary>
-/// Wrapper class that synchronously handles a base exception from request
-/// </summary>
-/// <typeparam name="TRequest">Request type</typeparam>
-/// <typeparam name="TResponse">Response type</typeparam>
-public abstract class RequestExceptionHandler<TRequest, TResponse> : IRequestExceptionHandler<TRequest, TResponse>
-    where TRequest : notnull
-{
-    Task IRequestExceptionHandler<TRequest, TResponse, Exception>.Handle(TRequest request, Exception exception, RequestExceptionHandlerState<TResponse> state, CancellationToken cancellationToken)
-    {
-        Handle(request, exception, state);
-        return Task.CompletedTask;
-    }
-
-    /// <summary>
-    /// Override in a derived class for the handler logic
-    /// </summary>
-    /// <param name="request">Failed request</param>
-    /// <param name="exception">The thrown exception</param>
-    /// <param name="state">The current state of handling the exception</param>
-    protected abstract void Handle(TRequest request, Exception exception, RequestExceptionHandlerState<TResponse> state);
-}

src/MediatR/Pipeline/RequestExceptionProcessorBehavior.cs

@@ -11,8 +11,7 @@ namespace MediatR.Pipeline;
 using System.Threading.Tasks;
 
 /// <summary>
-/// Behavior for executing all <see cref="IRequestExceptionHandler{TRequest,TResponse,TException}"/>
-///     or <see cref="RequestExceptionHandler{TRequest,TResponse}"/> instances
+/// Behavior for executing all <see cref="IRequestExceptionHandler{TRequest,TResponse,TException}"/> instances
 ///     after an exception is thrown by the following pipeline steps
 /// </summary>
 /// <typeparam name="TRequest">Request type</typeparam>

test/MediatR.Tests/MicrosoftExtensionsDI/PipelineTests.cs

@@ -235,7 +235,7 @@ public Task Process(Ping request, Pong response, CancellationToken cancellationT
         }
     }
 
-    public class PingPongGenericExceptionAction : IRequestExceptionAction<Ping>
+    public class PingPongGenericExceptionAction : IRequestExceptionAction<Ping, Exception>
     {
         private readonly Logger _output;
 
@@ -301,7 +301,7 @@ public Task Handle(Ping request, ApplicationException exception, RequestExceptio
         }
     }
 
-    public class PingPongGenericExceptionHandler : IRequestExceptionHandler<Ping, Pong>
+    public class PingPongGenericExceptionHandler : IRequestExceptionHandler<Ping, Pong, Exception>
     {
         private readonly Logger _output;
 

test/MediatR.Tests/Pipeline/RequestExceptionActionTests.cs

@@ -49,7 +49,7 @@ public Task<Pong> Handle(Ping request, CancellationToken cancellationToken)
         }
     }
 
-    public class GenericExceptionAction<TRequest> : IRequestExceptionAction<TRequest> where TRequest : notnull
+    public class GenericExceptionAction<TRequest> : IRequestExceptionAction<TRequest, Exception> where TRequest : notnull
     {
         public int ExecutionCount { get; private set; }
 
@@ -126,7 +126,7 @@ public async Task Should_run_matching_exception_actions_only_once()
         var container = new Container(cfg =>
         {
             cfg.For<IRequestHandler<Ping, Pong>>().Use<PingHandler>();
-            cfg.For<IRequestExceptionAction<Ping>>().Use(_ => genericExceptionAction);
+            cfg.For<IRequestExceptionAction<Ping, Exception>>().Use(_ => genericExceptionAction);
             cfg.For(typeof(IPipelineBehavior<,>)).Add(typeof(RequestExceptionActionProcessorBehavior<,>));
             cfg.For<IMediator>().Use<Mediator>();
         });

test/MediatR.Tests/Pipeline/RequestExceptionHandlerTests.cs

@@ -35,7 +35,7 @@ public Task<Pong> Handle(Ping request, CancellationToken cancellationToken)
         }
     }
 
-    public class GenericPingExceptionHandler : IRequestExceptionHandler<Ping, Pong>
+    public class GenericPingExceptionHandler : IRequestExceptionHandler<Ping, Pong, Exception>
     {
         public int ExecutionCount { get; private set; }
 
@@ -56,25 +56,29 @@ public Task Handle(Ping request, PingException exception, RequestExceptionHandle
         }
     }
 
-    public class PingPongExceptionHandler : RequestExceptionHandler<Ping, Pong>
+    public class PingPongExceptionHandler : IRequestExceptionHandler<Ping, Pong, Exception>
     {
-        protected override void Handle(Ping request, Exception exception, RequestExceptionHandlerState<Pong> state)
+        public Task Handle(Ping request, Exception exception, RequestExceptionHandlerState<Pong> state, CancellationToken token)
         {
             state.SetHandled(new Pong() { Message = exception.Message + " Handled"});
+
+            return Task.CompletedTask;
         }
     }
 
-    public class PingPongExceptionHandlerNotHandled : RequestExceptionHandler<Ping, Pong>
+    public class PingPongExceptionHandlerNotHandled : IRequestExceptionHandler<Ping, Pong, Exception>
     {
-        protected override void Handle(Ping request, Exception exception, RequestExceptionHandlerState<Pong> state)
+        public Task Handle(Ping request, Exception exception, RequestExceptionHandlerState<Pong> state, CancellationToken token)
         {
             request.Message = exception.Message + " Not Handled";
+
+            return Task.CompletedTask;
         }
     }
 
-    public class PingPongThrowingExceptionHandler : RequestExceptionHandler<Ping, Pong>
+    public class PingPongThrowingExceptionHandler : IRequestExceptionHandler<Ping, Pong, Exception>
     {
-        protected override void Handle(Ping request, Exception exception, RequestExceptionHandlerState<Pong> state)
+        public Task Handle(Ping request, Exception exception, RequestExceptionHandlerState<Pong> state, CancellationToken token)
         {
             throw new ApplicationException("Surprise!");
         }
@@ -148,7 +152,7 @@ public async Task Should_run_matching_exception_handlers_only_once()
         var container = new Container(cfg =>
         {
             cfg.For<IRequestHandler<Ping, Pong>>().Use<PingHandler>();
-            cfg.For<IRequestExceptionHandler<Ping, Pong>>().Use(genericPingExceptionHandler);
+            cfg.For<IRequestExceptionHandler<Ping, Pong, Exception>>().Use(genericPingExceptionHandler);
             cfg.For(typeof(IPipelineBehavior<,>)).Add(typeof(RequestExceptionProcessorBehavior<,>));
             cfg.For<IMediator>().Use<Mediator>();
         });