#264 Improved exception handling with IExceptionHandler (#276)

src/NKZSoft.Template.Application/Common/Behaviours/LoggingBehaviour.cs

@@ -7,7 +7,7 @@ public sealed class LoggingBehaviour<TRequest> : IRequestPreProcessor<TRequest>
 {
     private readonly ILogger _logger;
 
-    public LoggingBehaviour(ILogger<TRequest> logger, ICurrentUserService currentUserService) => _logger = logger.ThrowIfNull();
+    public LoggingBehaviour(ILogger<LoggingBehaviour<TRequest>> logger, ICurrentUserService currentUserService) => _logger = logger.ThrowIfNull();
 
     public async Task Process(TRequest request, CancellationToken cancellationToken)
     {

src/NKZSoft.Template.Application/Common/Behaviours/PerformanceBehaviour.cs

@@ -6,9 +6,9 @@ public sealed class PerformanceBehaviour<TRequest, TResponse> : IPipelineBehavio
     where TRequest : IRequest<TResponse>
 {
     private readonly Stopwatch _timer;
-    private readonly ILogger<TRequest> _logger;
+    private readonly ILogger<PerformanceBehaviour<TRequest, TResponse>> _logger;
 
-    public PerformanceBehaviour(ILogger<TRequest> logger)
+    public PerformanceBehaviour(ILogger<PerformanceBehaviour<TRequest, TResponse>> logger)
     {
         _logger = logger.ThrowIfNull();
         _timer = new Stopwatch();

src/NKZSoft.Template.Application/Common/Behaviours/UnhandledExceptionBehaviour.cs

@@ -4,19 +4,19 @@
 
 public sealed class UnhandledExceptionBehaviour<TRequest, TResponse> : IPipelineBehavior<TRequest, TResponse> where TRequest : notnull, IRequest<TResponse>
 {
-    private readonly ILogger<TRequest> _logger;
+    private readonly ILogger<UnhandledExceptionBehaviour<TRequest, TResponse>> _logger;
 
-    public UnhandledExceptionBehaviour(ILogger<TRequest> logger) => _logger = logger.ThrowIfNull();
+    public UnhandledExceptionBehaviour(ILogger<UnhandledExceptionBehaviour<TRequest, TResponse>> logger) => _logger = logger.ThrowIfNull();
 
     public async Task<TResponse> Handle(TRequest request, RequestHandlerDelegate<TResponse> next, CancellationToken cancellationToken)
     {
         try
         {
             return await next();
         }
-        catch (Exception ex)
+        catch (Exception)
         {
-            _logger.UnhandledExceptionRequest(request.ToString(), ex);
+            _logger.UnhandledExceptionRequest(request.ToString());
             throw;
         }
     }

src/NKZSoft.Template.Application/DependencyInjection.cs

@@ -6,11 +6,12 @@ public static class DependencyInjection
 {
     public static IServiceCollection AddApplication(this IServiceCollection services)
     {
+        services.ThrowIfNull();
+
         services.AddValidatorsFromAssembly(Assembly.GetExecutingAssembly(), ServiceLifetime.Scoped, null, true);
         services.AddMediatR(cfg =>
             cfg.RegisterServicesFromAssemblies(Assembly.GetExecutingAssembly()));
 
-
         var typeAdapterConfig = TypeAdapterConfig.GlobalSettings;
         typeAdapterConfig.Scan(Assembly.GetExecutingAssembly());
 

src/NKZSoft.Template.Common/Extensions/LoggerExtension.cs

@@ -1,44 +1,25 @@
 namespace NKZSoft.Template.Common.Extensions;
 
-internal static class LoggerExtension
+public static partial class LoggerExtension
 {
-    private static readonly Action<ILogger, string, Exception?> _consumeIntegrationEvent = LoggerMessage.Define<string>(
-        LogLevel.Information,
-        EventIds.ConsumeIntegrationEvent,
-        "Integration event has been consumed: `{Message}`.");
+    [LoggerMessage(1, LogLevel.Information, "Integration event has been consumed: {Message}.")]
+    internal static partial void ConsumeIntegrationEvent(this ILogger logger, string message);
 
-    private static readonly Action<ILogger, string, Exception?> _raiseIntegrationEvent = LoggerMessage.Define<string>(
-        LogLevel.Information,
-        EventIds.RaiseIntegrationEvent,
-        "Domain event has been raised: `{Message}`.");
+    [LoggerMessage(2, LogLevel.Information, "Domain event has been raised: {Message}.")]
+    public static partial void RaiseIntegrationEvent(this ILogger logger, string message);
 
-    private static readonly Action<ILogger, long, string, Exception?> _longRunningRequest = LoggerMessage.Define<long, string>(
-        LogLevel.Warning,
-        EventIds.LongRunningRequest,
-        "Long running request: `{ElapsedMilliseconds}` milliseconds `{Request}.`");
+    [LoggerMessage(3, LogLevel.Warning, "Long running request: {ElapsedMilliseconds} milliseconds {Request}.")]
+    public static partial void LongRunningRequest(this ILogger logger, long elapsedMilliseconds, string request);
 
-    private static readonly Action<ILogger, string?, Exception?> _unhandledExceptionRequest = LoggerMessage.Define<string?>(
-        LogLevel.Error,
-        EventIds.UnhandledExceptionRequest,
-        "Unhandled exception has occured for request: `{Request}.`");
+    [LoggerMessage(4, LogLevel.Error, "Unhandled exception has occured for request: `{Request}.")]
+    public static partial void UnhandledExceptionRequest(this ILogger logger, string? request);
 
-    private static readonly Action<ILogger, string?, Exception?> _loggingRequest = LoggerMessage.Define<string?>(
-        LogLevel.Error,
-        EventIds.LoggingRequest,
-        "Request has executed: `{Request}.`");
+    [LoggerMessage(5, LogLevel.Error, "Request has executed: `{Request}.")]
+    public static partial void LoggingRequest(this ILogger logger, string? request);
 
-    public static void ConsumeIntegrationEvent(this ILogger logger, string message)
-        => _consumeIntegrationEvent(logger, message, null);
+    [LoggerMessage(6, LogLevel.Error, "An error occurred while migrating or initializing the database.")]
+    public static partial void MigrationError(this ILogger logger, Exception ex);
 
-    public static void RaiseIntegrationEvent(this ILogger logger, string message)
-        => _raiseIntegrationEvent(logger, message, null);
-
-    public static void LongRunningRequest(this ILogger logger, long elapsedMilliseconds, string request)
-        => _longRunningRequest(logger, elapsedMilliseconds, request, null);
-
-    public static void UnhandledExceptionRequest(this ILogger logger, string? request, Exception? ex)
-        => _unhandledExceptionRequest(logger, request, ex);
-
-    public static void LoggingRequest(this ILogger logger, string? request)
-        => _loggingRequest(logger, request, null);
+    [LoggerMessage(7, LogLevel.Error, "Application: An unhandled exception has occurred.")]
+    public static partial void ApplicationUnhandledException(this ILogger logger, Exception ex);
 }

src/NKZSoft.Template.Presentation.Rest/Extensions/ApplicationBuilderExtension.cs

@@ -1,22 +1,22 @@
 namespace NKZSoft.Template.Presentation.Rest.Extensions;
 
-using Middleware;
-
 public static class ApplicationBuilderExtension
 {
     public static IApplicationBuilder UseRestPresentation(
         this IApplicationBuilder app, IConfiguration configuration, IWebHostEnvironment env)
     {
+        app.ThrowIfNull();
+        configuration.ThrowIfNull();
+        env.ThrowIfNull();
+
         if (env.IsDevelopment())
         {
             app.UseDeveloperExceptionPage();
         }
 
-        app.UseSwagger(configuration);
-
-        app.UseCors("CorsPolicy");
-
-        app.UseMiddleware(typeof(ErrorHandlingMiddleware));
+        app.UseSwagger(configuration)
+            .UseCors("CorsPolicy")
+            .UseExceptionHandler();
 
         return app;
     }

src/NKZSoft.Template.Presentation.Rest/Extensions/ServiceCollectionExtension.cs

@@ -1,6 +1,7 @@
 namespace NKZSoft.Template.Presentation.Rest.Extensions;
 
 using Filters;
+using Middleware;
 
 public static class ServiceCollectionExtension
 {
@@ -22,6 +23,8 @@ public static IServiceCollection AddRestPresentation(
         services.AddHttpContextAccessor()
             .AddSwagger(configuration, Assembly.GetExecutingAssembly())
             .AddValidatorsFromAssemblyContaining<IApplicationDbContext>(ServiceLifetime.Scoped, null, true)
+            .AddExceptionHandler<GlobalExceptionHandler>()
+            .AddProblemDetails()
             .AddControllers(options => options.Filters.Add<CustomExceptionFilterAttribute>())
             .AddApplicationPart(Assembly.GetExecutingAssembly());
 

src/NKZSoft.Template.Presentation.Rest/GlobalUsings.cs

@@ -20,6 +20,7 @@
 global using FluentResults;
 global using FluentValidation;
 global using Microsoft.AspNetCore.Builder;
+global using Microsoft.AspNetCore.Diagnostics;
 global using Microsoft.AspNetCore.Mvc.ModelBinding;
 global using Microsoft.AspNetCore.Routing;
 global using NKZSoft.Template.Application.Common.Interfaces;

src/NKZSoft.Template.Presentation.Rest/Middleware/ErrorHandlingMiddleware.cs

@@ -1,5 +1,6 @@
 namespace NKZSoft.Template.Presentation.Rest.Middleware;
 
+using Common.Extensions;
 using ILogger = Microsoft.Extensions.Logging.ILogger;
 
 public class ErrorHandlingMiddleware
@@ -27,9 +28,7 @@ public async Task Invoke(HttpContext httpContext)
 
     private static async Task HandleExceptionAsync(HttpContext context, ILogger log, Exception exception)
     {
-#pragma warning disable CA1848
-        log.LogError(exception, "Application: An unhandled exception has occurred");
-#pragma warning restore CA1848
+        log.ApplicationUnhandledException(exception);
 
         const HttpStatusCode code = HttpStatusCode.InternalServerError;
         var resultDto = new ResultDto<Unit>(Unit.Value, false, new[] { new ErrorDto(exception.Message, code.ToString()) });

src/NKZSoft.Template.Presentation.Rest/Middleware/GlobalExceptionHandler.cs

@@ -0,0 +1,30 @@
+namespace NKZSoft.Template.Presentation.Rest.Middleware;
+
+using Common.Extensions;
+
+public class GlobalExceptionHandler(ILogger<GlobalExceptionHandler> logger) : IExceptionHandler
+{
+    public async ValueTask<bool> TryHandleAsync(HttpContext httpContext, Exception exception, CancellationToken cancellationToken)
+    {
+        logger.ApplicationUnhandledException(exception);
+
+        var problemDetails = new ProblemDetails { Instance = httpContext.Request.Path };
+        if (exception is ValidationException fluentException)
+        {
+            problemDetails.Title = "one or more validation errors occurred.";
+            problemDetails.Type = "https://tools.ietf.org/html/rfc7231#section-6.5.1";
+            httpContext.Response.StatusCode = StatusCodes.Status400BadRequest;
+            var validationErrors =
+                fluentException.Errors.Select(error => error.ErrorMessage).ToList();
+            problemDetails.Extensions.Add("errors", validationErrors);
+        }
+        else
+        {
+            problemDetails.Title = exception.Message;
+        }
+
+        problemDetails.Status = httpContext.Response.StatusCode;
+        await httpContext.Response.WriteAsJsonAsync(problemDetails, cancellationToken).ConfigureAwait(false);
+        return true;
+    }
+}

src/NKZSoft.Template.Presentation.Starter/Program.cs

@@ -1,3 +1,5 @@
+using NKZSoft.Template.Common.Extensions;
+
 var builder = WebApplication.CreateBuilder(args);
 
 builder.Configuration
@@ -36,12 +38,12 @@
     .AddHealthChecks();
 
 builder.Services.AddOpenTelemetry()
-    .ConfigureResource(builder => builder
+    .ConfigureResource(b => b
         .AddService(
             serviceName: Assembly.GetExecutingAssembly().GetName().Name!,
             serviceVersion: Assembly.GetExecutingAssembly().GetName().Version?.ToString(),
             serviceInstanceId: Environment.MachineName))
-    .WithTracing(builder => builder
+    .WithTracing(b => b
         .AddAspNetCoreInstrumentation(options =>
         {
             options.RecordException = true;
@@ -66,9 +68,7 @@
     catch (Exception ex)
     {
         var logger = scope.ServiceProvider.GetRequiredService<ILogger<Program>>();
-#pragma warning disable CA1848
-        logger.LogError(ex, "An error occurred while migrating or initializing the database.");
-#pragma warning restore CA1848
+        logger.MigrationError(ex);
     }
 }