Add Domain project and shifted handlers to application.

wolverine/a-frame-architecture/FinancialApi/DomainExceptionHandler.cs

@@ -0,0 +1,32 @@
+using Microsoft.AspNetCore.Diagnostics;
+using Microsoft.AspNetCore.Mvc;
+
+namespace FinancialApi;
+
+public class DomainExceptionHandler : IExceptionHandler
+{
+    public async ValueTask<bool> TryHandleAsync(
+        HttpContext httpContext, 
+        Exception exception, 
+        CancellationToken cancellationToken)
+    {
+        // Only intercept our specific domain/validation exceptions
+        if (exception is InvalidOperationException or ArgumentException)
+        {
+            var problemDetails = new ProblemDetails
+            {
+                Status = StatusCodes.Status400BadRequest,
+                Title = "Domain Validation Error",
+                Detail = exception.Message,
+                Type = "https://datatracker.ietf.org/doc/html/rfc7231#section-6.5.1"
+            };
+
+            httpContext.Response.StatusCode = problemDetails.Status.Value;
+            await httpContext.Response.WriteAsJsonAsync(problemDetails, cancellationToken);
+            
+            return true;
+        }
+
+        return false; 
+    }
+}

wolverine/a-frame-architecture/FinancialApi/Program.cs

@@ -1,4 +1,5 @@
 using FinancialApi;
+using FinancialApi.Application;
 using FinancialApi.Infrastructure;
 using FinancialApi.ServiceDefaults;
 using JasperFx.CodeGeneration;
@@ -11,11 +12,16 @@ using Wolverine.Sqlite;
 
 var builder = WebApplication.CreateBuilder(args);
 
+builder.Services.AddExceptionHandler<DomainExceptionHandler>();
+builder.Services.AddProblemDetails();
+
 var connectionString = "Data Source=demo.db";
 
 builder.Services.AddDbContext<AccountDbContext>(options =>
     options.UseSqlite(connectionString));
 
+builder.Services.AddScoped<IAccountQuery, AccountQuery>();
+
 // Add services to the container.
 // Learn more about configuring OpenAPI at https://aka.ms/aspnet/openapi
 builder.Services.AddOpenApi();
@@ -33,6 +39,8 @@ builder.Host.UseResourceSetupOnStartup();
 
 var app = builder.Build();
 
+app.UseExceptionHandler();
+
 using (var scope = app.Services.CreateScope())
 {
     var db = scope.ServiceProvider.GetRequiredService<AccountDbContext>();