Add configure-once ProblemDetails customization for Minimal API

src/Ardalis.Result.AspNetCore/MinimalApiResultExtensions.cs

@@ -42,17 +42,36 @@ internal static Microsoft.AspNetCore.Http.IResult ToMinimalApiResult(this IResul
             _ => throw new NotSupportedException($"Result {result.Status} conversion is not supported."),
         };
 
+    // Invoke the optional global customization hook (if configured) on the ProblemDetails before returning it,
+    // so consumers can adjust Title/Detail/Extensions without reimplementing the conversion. See ResultProblemDetailsOptions.
+    private static ProblemDetails ApplyCustomization(IResult result, int statusCode, ProblemDetails problemDetails)
+    {
+        var customize = ResultProblemDetailsOptions.Customize;
+        if (customize != null)
+        {
+            customize(new ResultProblemDetailsContext
+            {
+                ResultStatus = result.Status,
+                StatusCode = statusCode,
+                Result = result,
+                ProblemDetails = problemDetails
+            });
+        }
+
+        return problemDetails;
+    }
+
     private static Microsoft.AspNetCore.Http.IResult UnprocessableEntity(IResult result)
     {
         var details = new StringBuilder("Next error(s) occurred:");
 
         foreach (var error in result.Errors) details.Append("* ").Append(error).AppendLine();
 
-        return Results.UnprocessableEntity(new ProblemDetails
+        return Results.UnprocessableEntity(ApplyCustomization(result, StatusCodes.Status422UnprocessableEntity, new ProblemDetails
         {
             Title = "Something went wrong.",
             Detail = details.ToString()
-        });
+        }));
     }
 
     private static Microsoft.AspNetCore.Http.IResult NotFoundEntity(IResult result)
@@ -63,11 +82,11 @@ private static Microsoft.AspNetCore.Http.IResult NotFoundEntity(IResult result)
         {
             foreach (var error in result.Errors) details.Append("* ").Append(error).AppendLine();
 
-            return Results.NotFound(new ProblemDetails
+            return Results.NotFound(ApplyCustomization(result, StatusCodes.Status404NotFound, new ProblemDetails
             {
                 Title = "Resource not found.",
                 Detail = details.ToString()
-            });
+            }));
         }
         else
         {
@@ -83,11 +102,11 @@ private static Microsoft.AspNetCore.Http.IResult ConflictEntity(IResult result)
         {
             foreach (var error in result.Errors) details.Append("* ").Append(error).AppendLine();
 
-            return Results.Conflict(new ProblemDetails
+            return Results.Conflict(ApplyCustomization(result, StatusCodes.Status409Conflict, new ProblemDetails
             {
                 Title = "There was a conflict.",
                 Detail = details.ToString()
-            });
+            }));
         }
         else
         {
@@ -103,12 +122,12 @@ private static Microsoft.AspNetCore.Http.IResult CriticalEntity(IResult result)
         {
             foreach (var error in result.Errors) details.Append("* ").Append(error).AppendLine();
 
-            return Results.Problem(new ProblemDetails()
+            return Results.Problem(ApplyCustomization(result, StatusCodes.Status500InternalServerError, new ProblemDetails()
             {
                 Title = "Something went wrong.",
                 Detail = details.ToString(),
                 Status = StatusCodes.Status500InternalServerError
-            });
+            }));
         }
         else
         {
@@ -124,12 +143,12 @@ private static Microsoft.AspNetCore.Http.IResult UnavailableEntity(IResult resul
         {
             foreach (var error in result.Errors) details.Append("* ").Append(error).AppendLine();
 
-            return Results.Problem(new ProblemDetails
+            return Results.Problem(ApplyCustomization(result, StatusCodes.Status503ServiceUnavailable, new ProblemDetails
             {
                 Title = "Service unavailable.",
                 Detail = details.ToString(),
                 Status = StatusCodes.Status503ServiceUnavailable
-            });
+            }));
         }
         else
         {
@@ -145,12 +164,12 @@ private static Microsoft.AspNetCore.Http.IResult Forbidden(IResult result)
         {
             foreach (var error in result.Errors) details.Append("* ").Append(error).AppendLine();
 
-            return Results.Problem(new ProblemDetails
+            return Results.Problem(ApplyCustomization(result, StatusCodes.Status403Forbidden, new ProblemDetails
             {
                 Title = "Forbidden.",
                 Detail = details.ToString(),
                 Status = StatusCodes.Status403Forbidden
-            });
+            }));
         }
         else
         {
@@ -166,12 +185,12 @@ private static Microsoft.AspNetCore.Http.IResult UnAuthorized(IResult result)
         {
             foreach (var error in result.Errors) details.Append("* ").Append(error).AppendLine();
 
-            return Results.Problem(new ProblemDetails
+            return Results.Problem(ApplyCustomization(result, StatusCodes.Status401Unauthorized, new ProblemDetails
             {
                 Title = "Unauthorized.",
                 Detail = details.ToString(),
                 Status = StatusCodes.Status401Unauthorized
-            });
+            }));
         }
         else
         {

src/Ardalis.Result.AspNetCore/ResultProblemDetailsOptions.cs

@@ -0,0 +1,46 @@
+#if NET6_0_OR_GREATER
+#nullable enable
+using System;
+
+using Microsoft.AspNetCore.Mvc;
+
+namespace Ardalis.Result.AspNetCore;
+
+/// <summary>
+/// Context passed to <see cref="ResultProblemDetailsOptions.Customize"/> when the Minimal API
+/// <c>ToMinimalApiResult</c> extensions build a <see cref="ProblemDetails"/> for an error-class result.
+/// </summary>
+public sealed class ResultProblemDetailsContext
+{
+    /// <summary>The Ardalis.Result status that produced this response.</summary>
+    public required ResultStatus ResultStatus { get; init; }
+
+    /// <summary>The HTTP status code that will be returned.</summary>
+    public required int StatusCode { get; init; }
+
+    /// <summary>The result being converted.</summary>
+    public required IResult Result { get; init; }
+
+    /// <summary>
+    /// The <see cref="ProblemDetails"/> about to be returned. Mutate it in place (Title, Detail,
+    /// Extensions, ...) to customize the response.
+    /// </summary>
+    public required ProblemDetails ProblemDetails { get; init; }
+}
+
+/// <summary>
+/// Global, configure-once customization for the <see cref="ProblemDetails"/> produced by the Minimal API
+/// <c>ToMinimalApiResult</c> extensions. Mirrors the spirit of ASP.NET Core's
+/// <c>ProblemDetailsOptions.CustomizeProblemDetails</c>, but applies to the Ardalis.Result conversion which
+/// runs without access to an <c>HttpContext</c>.
+/// </summary>
+public static class ResultProblemDetailsOptions
+{
+    /// <summary>
+    /// Optional hook to customize the <see cref="ProblemDetails"/> produced for error-class results. Null by
+    /// default, leaving the library's formatting unchanged. Set once at application startup, e.g. to remove the
+    /// default "Next error(s) occurred:" Detail prefix or to localize the Title.
+    /// </summary>
+    public static Action<ResultProblemDetailsContext>? Customize { get; set; }
+}
+#endif

tests/Ardalis.Result.AspNetCore.UnitTests/MinimalApiResultProblemDetailsCustomizationTests.cs

@@ -0,0 +1,72 @@
+#if NET6_0_OR_GREATER
+
+using System;
+using System.Reflection;
+
+using Ardalis.Result.AspNetCore;
+using Microsoft.AspNetCore.Mvc;
+using Xunit;
+
+namespace Ardalis.Result.AspNetCore.UnitTests;
+
+public class MinimalApiResultProblemDetailsCustomizationTests : IDisposable
+{
+    // Customize is global static; reset after every test so cases stay isolated.
+    public void Dispose() => ResultProblemDetailsOptions.Customize = null;
+
+    [Fact]
+    public void WithoutCustomization_DefaultTitleAndDetailAreUnchanged()
+    {
+        ResultProblemDetailsOptions.Customize = null;
+
+        var problemDetails = ExtractProblemDetails(Result<int>.Error("boom").ToMinimalApiResult());
+
+        Assert.Equal("Something went wrong.", problemDetails.Title);
+        Assert.StartsWith("Next error(s) occurred:", problemDetails.Detail);
+    }
+
+    [Fact]
+    public void Customize_CanRewriteTitleAndDetail()
+    {
+        ResultProblemDetailsOptions.Customize = context =>
+        {
+            context.ProblemDetails.Title = "Custom title";
+            context.ProblemDetails.Detail = string.Join("; ", context.Result.Errors);
+        };
+
+        var problemDetails = ExtractProblemDetails(Result<int>.Error("boom").ToMinimalApiResult());
+
+        Assert.Equal("Custom title", problemDetails.Title);
+        Assert.Equal("boom", problemDetails.Detail);
+    }
+
+    [Fact]
+    public void Customize_ReceivesResultStatusAndStatusCode()
+    {
+        ResultProblemDetailsContext captured = null;
+        ResultProblemDetailsOptions.Customize = context => captured = context;
+
+        Result<int>.Conflict("nope").ToMinimalApiResult();
+
+        Assert.NotNull(captured);
+        Assert.Equal(ResultStatus.Conflict, captured.ResultStatus);
+        Assert.Equal(409, captured.StatusCode);
+    }
+
+    // The concrete result type returned by Results.UnprocessableEntity/Conflict/Problem differs across target
+    // frameworks (and is internal on net6), so read the ProblemDetails reflectively by well-known property name.
+    private static ProblemDetails ExtractProblemDetails(Microsoft.AspNetCore.Http.IResult result)
+    {
+        const BindingFlags flags = BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance;
+        var type = result.GetType();
+        foreach (var propertyName in new[] { "ProblemDetails", "Value" })
+        {
+            if (type.GetProperty(propertyName, flags)?.GetValue(result) is ProblemDetails problemDetails)
+            {
+                return problemDetails;
+            }
+        }
+        throw new InvalidOperationException($"Could not extract ProblemDetails from {type.FullName}");
+    }
+}
+#endif