Merge pull request #95 from wemogy/fix/error-handling

fix: improved error handling in remote processing

.github/workflows/test.yaml

@@ -10,6 +10,9 @@ jobs:
   tests:
     name: Tests
     runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      pull-requests: write
     steps:
       - uses: actions/checkout@v3
 

src/core/Wemogy.CQRS/Wemogy.CQRS.csproj

@@ -21,6 +21,6 @@
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
       <PrivateAssets>all</PrivateAssets>
     </PackageReference>
-    <PackageReference Include="Wemogy.Core" Version="3.2.1" />
+    <PackageReference Include="Wemogy.Core" Version="3.2.2" />
   </ItemGroup>
 </Project>

src/extensions/fastEndpoints/Wemogy.CQRS.Extensions.FastEndpoints.TestWebApp/Commands/ThrowError/ThrowErrorCommandHandler.cs

@@ -1,25 +1,36 @@
+using Wemogy.Core.Errors;
 using Wemogy.Core.Errors.Enums;
-using Wemogy.Core.Errors.Exceptions;
 using Wemogy.CQRS.Commands.Abstractions;
 
 namespace Wemogy.CQRS.Extensions.FastEndpoints.TestWebApp.Commands.ThrowError;
 
 public class ThrowErrorCommandHandler : ICommandHandler<ThrowErrorCommand>
 {
-    public Task HandleAsync(ThrowErrorCommand command)
-    {
-        throw new CustomErrorException(
-            command.ErrorType,
-            "CustomError",
-            "This is a custom error",
-            null);
-    }
+    private const string DummyErrorCode = "DummyErrorCode";
+    private const string DummyErrorDescription = "DummyErrorDescription";
 
-    class CustomErrorException : ErrorException
+    public Task HandleAsync(ThrowErrorCommand command)
     {
-        public CustomErrorException(ErrorType errorType, string code, string description, Exception? innerException)
-            : base(errorType, code, description, innerException)
+        switch (command.ErrorType)
         {
+            case ErrorType.Failure:
+                throw Error.Failure(DummyErrorCode, DummyErrorDescription);
+            case ErrorType.Unexpected:
+                throw Error.Unexpected(DummyErrorCode, DummyErrorDescription);
+            case ErrorType.Validation:
+                throw Error.Validation(DummyErrorCode, DummyErrorDescription);
+            case ErrorType.Conflict:
+                throw Error.Conflict(DummyErrorCode, DummyErrorDescription);
+            case ErrorType.NotFound:
+                throw Error.NotFound(DummyErrorCode, DummyErrorDescription);
+            case ErrorType.Authorization:
+                throw Error.Authorization(DummyErrorCode, DummyErrorDescription);
+            case ErrorType.PreconditionFailed:
+                throw Error.PreconditionFailed(DummyErrorCode, DummyErrorDescription);
         }
+
+        throw Error.Unexpected(
+            "ErrorTypeNotSupported",
+            $"The ErrorType {command.ErrorType} is not supported!");
     }
 }

src/extensions/fastEndpoints/Wemogy.CQRS.Extensions.FastEndpoints.UnitTests/Endpoints/CommandEndpointBaseExceptionTests.cs

@@ -0,0 +1,46 @@
+using FluentAssertions;
+using Microsoft.AspNetCore.Mvc.Testing;
+using Wemogy.Core.Errors.Enums;
+using Wemogy.Core.Errors.Exceptions;
+using Wemogy.CQRS.Commands.Abstractions;
+using Wemogy.CQRS.Extensions.FastEndpoints.TestWebApp.Commands.ThrowError;
+
+namespace Wemogy.CQRS.Extensions.FastEndpoints.UnitTests.Endpoints;
+
+public class CommandEndpointBaseExceptionTests : IClassFixture<WebApplicationFactory<Program>>
+{
+    private readonly WebApplicationFactory<Program> _factory;
+
+    public CommandEndpointBaseExceptionTests(WebApplicationFactory<Program> factory)
+    {
+        _factory = factory;
+    }
+
+    [Theory]
+    [InlineData(ErrorType.Failure)]
+    [InlineData(ErrorType.Unexpected)]
+    [InlineData(ErrorType.Validation)]
+    [InlineData(ErrorType.Conflict)]
+    [InlineData(ErrorType.NotFound)]
+    [InlineData(ErrorType.Authorization)]
+    [InlineData(ErrorType.PreconditionFailed)]
+    public async Task PrintHelloWorldCommand_ShouldReturnCorrectErrorException(ErrorType errorType)
+    {
+        // Arrange
+        var client = _factory.CreateClient();
+        var serviceCollection = new ServiceCollection();
+        serviceCollection.AddCQRS(typeof(ThrowErrorCommand).Assembly)
+            .AddRemoteHttpServer(client)
+            .ConfigureRemoteCommandProcessing<ThrowErrorCommand>("api/commands/throw-error");
+        var commands = serviceCollection.BuildServiceProvider().GetRequiredService<ICommands>();
+        var throwErrorCommand = new ThrowErrorCommand(errorType);
+
+        // Act
+        var exception = await Record.ExceptionAsync(() => commands.RunAsync(throwErrorCommand));
+
+        // Assert
+        exception.Should().NotBeNull().And.BeAssignableTo<ErrorException>()
+            .Which.ErrorType.Should().Be(errorType);
+        exception?.GetType().Name.Should().Be($"{errorType}ErrorException");
+    }
+}

src/extensions/fastEndpoints/Wemogy.CQRS.Extensions.FastEndpoints.UnitTests/Extensions/PostProcessorContextExtensionsTests.cs

@@ -0,0 +1,71 @@
+using FastEndpoints;
+using FluentAssertions;
+using Moq;
+using Wemogy.CQRS.Extensions.FastEndpoints.Extensions;
+
+namespace Wemogy.CQRS.Extensions.FastEndpoints.UnitTests.Extensions;
+
+public class PostProcessorContextExtensionsTests
+{
+    /// <summary>
+    /// This method checks if the MarkExceptionAsHandled implementation from FastEndpoints is working as expected
+    /// This is required, because the implementation is only internal accessible, so we need to hardcode the key
+    /// </summary>
+    [Fact]
+    public void MarkExceptionAsHandled_ShouldHaveTheExpectedImplementation()
+    {
+        // Arrange
+        var defaultHttpContext = new DefaultHttpContext();
+        var mockContext = new Mock<IPostProcessorContext>
+        {
+            // enable CallBase to tell Moq to use the default interface implementations (like MarkExceptionAsHandled)
+            CallBase = true
+        };
+        mockContext.SetupGet(m => m.HttpContext).Returns(defaultHttpContext);
+
+        // Act
+        mockContext.Object.MarkExceptionAsHandled();
+
+        // Assert
+        defaultHttpContext.Items.Should().ContainSingle(x => ReferenceEquals(x.Key, "3") && x.Value == null);
+    }
+
+    [Fact]
+    public void IsExceptionHandled_ShouldBeTrueIfMarkExceptionAsHandledWasCalled()
+    {
+        // Arrange
+        var defaultHttpContext = new DefaultHttpContext();
+        var mockContext = new Mock<IPostProcessorContext>
+        {
+            // enable CallBase to tell Moq to use the default interface implementations (like MarkExceptionAsHandled)
+            CallBase = true
+        };
+        mockContext.SetupGet(m => m.HttpContext).Returns(defaultHttpContext);
+        mockContext.Object.MarkExceptionAsHandled();
+
+        // Act
+        var result = mockContext.Object.IsExceptionHandled();
+
+        // Assert
+        result.Should().BeTrue();
+    }
+
+    [Fact]
+    public void IsExceptionHandled_ShouldBeFalseIfMarkExceptionAsHandledWasNotCalled()
+    {
+        // Arrange
+        var defaultHttpContext = new DefaultHttpContext();
+        var mockContext = new Mock<IPostProcessorContext>
+        {
+            // enable CallBase to tell Moq to use the default interface implementations (like MarkExceptionAsHandled)
+            CallBase = true
+        };
+        mockContext.SetupGet(m => m.HttpContext).Returns(defaultHttpContext);
+
+        // Act
+        var result = mockContext.Object.IsExceptionHandled();
+
+        // Assert
+        result.Should().BeFalse();
+    }
+}

src/extensions/fastEndpoints/Wemogy.CQRS.Extensions.FastEndpoints.UnitTests/Wemogy.CQRS.Extensions.FastEndpoints.UnitTests.csproj

@@ -12,6 +12,7 @@
         <PackageReference Include="FluentAssertions" Version="6.12.0" />
         <PackageReference Include="Microsoft.AspNetCore.Mvc.Testing" Version="8.0.6" />
         <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.6.0"/>
+        <PackageReference Include="Moq" Version="4.20.70" />
         <PackageReference Include="xunit" Version="2.4.2"/>
         <PackageReference Include="xunit.runner.visualstudio" Version="2.4.5">
             <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>

src/extensions/fastEndpoints/Wemogy.CQRS.Extensions.FastEndpoints/Endpoints/CommandEndpointBase`1.cs

@@ -7,6 +7,7 @@
 using Wemogy.CQRS.Abstractions;
 using Wemogy.CQRS.Commands.Abstractions;
 using Wemogy.CQRS.Common.ValueObjects;
+using Wemogy.CQRS.Extensions.FastEndpoints.PostProcessors;
 using Wemogy.CQRS.Setup;
 using ICommand = Wemogy.CQRS.Commands.Abstractions.ICommand;
 
@@ -30,6 +31,7 @@ public override void Configure()
 
         // ToDo: remove this
         AllowAnonymous();
+        PostProcessor<CqrsEndpointExceptionPostProcessor<CommandRequest<TCommand>>>();
     }
 
     public override async Task HandleAsync(CommandRequest<TCommand> req, CancellationToken ct)

src/extensions/fastEndpoints/Wemogy.CQRS.Extensions.FastEndpoints/Endpoints/CommandEndpointBase`2.cs

@@ -7,6 +7,7 @@
 using Wemogy.CQRS.Abstractions;
 using Wemogy.CQRS.Commands.Abstractions;
 using Wemogy.CQRS.Common.ValueObjects;
+using Wemogy.CQRS.Extensions.FastEndpoints.PostProcessors;
 using Wemogy.CQRS.Setup;
 
 namespace Wemogy.CQRS.Extensions.FastEndpoints.Endpoints;
@@ -29,6 +30,7 @@ public override void Configure()
 
         // ToDo: remove this
         AllowAnonymous();
+        PostProcessor<CqrsEndpointExceptionPostProcessor<CommandRequest<TCommand>, TResult>>();
     }
 
     public override async Task HandleAsync(CommandRequest<TCommand> req, CancellationToken ct)

src/extensions/fastEndpoints/Wemogy.CQRS.Extensions.FastEndpoints/Endpoints/QueryEndpointBase.cs

@@ -7,6 +7,7 @@
 using Wemogy.Core.Extensions;
 using Wemogy.CQRS.Abstractions;
 using Wemogy.CQRS.Common.ValueObjects;
+using Wemogy.CQRS.Extensions.FastEndpoints.PostProcessors;
 using Wemogy.CQRS.Queries.Abstractions;
 using Wemogy.CQRS.Setup;
 
@@ -30,6 +31,7 @@ public override void Configure()
 
         // ToDo: remove this
         AllowAnonymous();
+        PostProcessor<CqrsEndpointExceptionPostProcessor<QueryRequest<TQuery>, TResult>>();
     }
 
     public override async Task HandleAsync(QueryRequest<TQuery> req, CancellationToken ct)

src/extensions/fastEndpoints/Wemogy.CQRS.Extensions.FastEndpoints/Extensions/EndpointDefinitionExtensions.cs

@@ -7,6 +7,7 @@ public static class EndpointDefinitionExtensions
 {
     public static void AddErrorHandlerPostProcessor(this EndpointDefinition endpointDefinition)
     {
-        endpointDefinition.PostProcessor<ErrorHandlerPostProcessor>(Order.Before);
+        // Add the global ErrorHandlerPostProcessor after the endpoint post processors are executed
+        endpointDefinition.PostProcessor<ErrorHandlerPostProcessor>(Order.After);
     }
 }

src/extensions/fastEndpoints/Wemogy.CQRS.Extensions.FastEndpoints/Extensions/PostProcessorContextExtensions.cs

@@ -0,0 +1,18 @@
+using FastEndpoints;
+
+namespace Wemogy.CQRS.Extensions.FastEndpoints.Extensions;
+
+public static class PostProcessorContextExtensions
+{
+    /// <summary>
+    /// The MarkExceptionAsHandled method add the CtxKey.EdiIsHandled key to the HttpContext.Items dictionary
+    /// This method checks if the CtxKey.EdiIsHandled key is present in the HttpContext.Items dictionary
+    /// </summary>
+    public static bool IsExceptionHandled(this IPostProcessorContext context)
+    {
+        // The CtxKey class is an internal class of FastEndpoints which means that we can't access it
+        // for that reason we hardcoded the value of the key
+        // The PostProcessorContextExtensionsTests class tests this implementation, so if the key changes the tests will fail
+        return context.HttpContext.Items.ContainsKey("3");
+    }
+}

src/extensions/fastEndpoints/Wemogy.CQRS.Extensions.FastEndpoints/PostProcessors/CqrsEndpointExceptionPostProcessor`1.cs

@@ -0,0 +1,5 @@
+namespace Wemogy.CQRS.Extensions.FastEndpoints.PostProcessors;
+
+public class CqrsEndpointExceptionPostProcessor<TRequest> : CqrsEndpointExceptionPostProcessor<TRequest, object?>
+{
+}

src/extensions/fastEndpoints/Wemogy.CQRS.Extensions.FastEndpoints/PostProcessors/CqrsEndpointExceptionPostProcessor`2.cs

@@ -0,0 +1,28 @@
+using System.Net;
+using FastEndpoints;
+using Wemogy.Core.Errors.Exceptions;
+using Wemogy.Core.Errors.Extensions;
+using Wemogy.Core.Json.ExceptionInformation;
+using Wemogy.CQRS.Extensions.FastEndpoints.Extensions;
+
+namespace Wemogy.CQRS.Extensions.FastEndpoints.PostProcessors;
+
+public class CqrsEndpointExceptionPostProcessor<TRequest, TResponse> : IPostProcessor<TRequest, TResponse>
+{
+    public Task PostProcessAsync(IPostProcessorContext<TRequest, TResponse> context, CancellationToken ct)
+    {
+        if (!context.HasExceptionOccurred)
+        {
+            return Task.CompletedTask;
+        }
+
+        var exception = context.ExceptionDispatchInfo.SourceException;
+
+        var statusCode = (exception as ErrorException)?.ErrorType.ToHttpStatusCode() ?? HttpStatusCode.InternalServerError;
+
+        context.MarkExceptionAsHandled();
+
+        context.HttpContext.Response.Headers.AppendJsonTypeHeader<ExceptionInformation>();
+        return context.HttpContext.Response.SendStringAsync(exception.ToJson(), (int)statusCode, cancellation: ct);
+    }
+}

src/extensions/fastEndpoints/Wemogy.CQRS.Extensions.FastEndpoints/PostProcessors/ErrorHandlerPostProcessor.cs

@@ -10,7 +10,7 @@ public class ErrorHandlerPostProcessor : IGlobalPostProcessor
 {
     public async Task PostProcessAsync(IPostProcessorContext context, CancellationToken ct)
     {
-        if (!context.HasExceptionOccurred)
+        if (!context.HasExceptionOccurred || context.IsExceptionHandled())
         {
             return;
         }

src/extensions/fastEndpoints/Wemogy.CQRS.Extensions.FastEndpoints/RemoteCommandRunners/HttpRemoteCommandRunner`1.cs

@@ -1,4 +1,5 @@
 using RestSharp;
+using Wemogy.Core.Errors;
 using Wemogy.Core.Extensions;
 using Wemogy.Core.Json.ExceptionInformation;
 using Wemogy.CQRS.Abstractions;
@@ -41,8 +42,17 @@ public async Task RunAsync(CommandRequest<TCommand> command)
                     throw response.ErrorException ?? new Exception(response.Content);
                 }
 
-                // ToDo: Handle the exception information
                 var exceptionInformation = response.Content?.FromJson<ExceptionInformation>();
+
+                if (exceptionInformation == null)
+                {
+                    throw Error.Unexpected(
+                        "ExceptionInformationMissing",
+                        "The response from the remote service did not contain any exception information.");
+                }
+
+                var exception = exceptionInformation.ToException();
+                throw exception;
             }
         }
         catch (HttpRequestException e)

src/extensions/fastEndpoints/Wemogy.CQRS.Extensions.FastEndpoints/RemoteCommandRunners/HttpRemoteCommandRunner`2.cs

@@ -1,9 +1,13 @@
 using System.Text.Json;
 using RestSharp;
+using Wemogy.Core.Errors;
+using Wemogy.Core.Extensions;
+using Wemogy.Core.Json.ExceptionInformation;
 using Wemogy.CQRS.Abstractions;
 using Wemogy.CQRS.Commands.Abstractions;
 using Wemogy.CQRS.Common.ValueObjects;
 using Wemogy.CQRS.Extensions.FastEndpoints.Common;
+using Wemogy.CQRS.Extensions.FastEndpoints.Extensions;
 
 namespace Wemogy.CQRS.Extensions.FastEndpoints.RemoteCommandRunners;
 
@@ -33,7 +37,22 @@ public async Task<TResult> RunAsync(CommandRequest<TCommand> command)
 
         if (!response.IsSuccessful)
         {
-            throw new Exception($"Failed to run command {command.Command.GetType().Name}");
+            if (response.Headers == null || !response.Headers.HasJsonTypeHeader<ExceptionInformation>())
+            {
+                throw response.ErrorException ?? new Exception(response.Content);
+            }
+
+            var exceptionInformation = response.Content?.FromJson<ExceptionInformation>();
+
+            if (exceptionInformation == null)
+            {
+                throw Error.Unexpected(
+                    "ExceptionInformationMissing",
+                    "The response from the remote service did not contain any exception information.");
+            }
+
+            var exception = exceptionInformation.ToException();
+            throw exception;
         }
 
         if (response.Content == null)