refactor(TaskExtensions): TaskExtensions verallgemeinern, um benutzerdefinierte Ausnahmegeneratoren zu unterstützen

- Feste NotFoundException durch generischen Ausnahmegenerator in ThrowIfNull-Methoden ersetzt.
- Neue Exceptions-Hilfsklasse für die Erstellung gängiger Ausnahmen (NotFound, BadRequest, Forbidden) hinzugefügt.
- Funktionalität der Then-Erweiterungsmethode unverändert beibehalten.

EnvelopeGenerator.Application/Extensions/TaskExtensions.cs

@@ -9,32 +9,34 @@ public static class TaskExtensions
 {
     /// <summary>
     /// Awaits the specified task and ensures that the result is not <c>null</c>.
-    /// If the result is <c>null</c>, a <see cref="NotFoundException"/> is thrown.
+    /// If the result is <c>null</c>, the exception created by factory-method is thrown.
     /// </summary>
     /// <typeparam name="T">The type of the result.</typeparam>
+    /// <typeparam name="TException">The type of the exception.</typeparam>
     /// <param name="task">The task to await.</param>
-    /// <param name="exceptionMessage">Optional custom exception message.</param>
+    /// <param name="factory">Exception provider</param>
     /// <returns>The awaited result if not <c>null</c>.</returns>
-    /// <exception cref="NotFoundException">Thrown if the result is <c>null</c>.</exception>
+    /// <exception>Thrown if the result is <c>null</c>.</exception>
-    public static async Task<T> ThrowIfNull<T>(this Task<T?> task, string? exceptionMessage = null)
+    public static async Task<T> ThrowIfNull<T, TException>(this Task<T?> task, Func<TException> factory) where TException : Exception
     {
         var result = await task;
-        return result ?? throw new NotFoundException(exceptionMessage);
+        return result ?? throw factory();
     }
 
     /// <summary>
     /// Awaits the specified task and ensures that the result is not <c>empty</c>.
-    /// If the result contains no elements, a <see cref="NotFoundException"/> is thrown.
+    /// If the result contains no elements, the exception created by factory-method is thrown.
     /// </summary>
     /// <typeparam name="T">The element type of the collection.</typeparam>
+    /// <typeparam name="TException">The type of the exception.</typeparam>
     /// <param name="task">The task to await.</param>
-    /// <param name="exceptionMessage">Optional custom exception message.</param>
+    /// <param name="factory">Exception provider</param>
     /// <returns>The awaited collection if it is not <c>null</c> or empty.</returns>
     /// <exception cref="NotFoundException">Thrown if the result is <c>null</c> or empty.</exception>
-    public static async Task<IEnumerable<T>> ThrowIfNull<T>(this Task<IEnumerable<T>> task, string? exceptionMessage = null)
+    public static async Task<IEnumerable<T>> ThrowIfNull<T, TException>(this Task<IEnumerable<T>> task, Func<TException> factory) where TException : Exception
     {
         var result = await task;
-        return result?.Any() ?? false ? result : throw new NotFoundException(exceptionMessage);
+        return result?.Any() ?? false ? result : throw factory();
     }
 
     /// <summary>
@@ -51,3 +53,26 @@ public static class TaskExtensions
         return act(res);
     }
 }
+
+/// <summary>
+/// 
+/// </summary>
+public static class Exceptions
+{
+    /// <summary>
+    /// 
+    /// </summary>
+    public static NotFoundException NotFound() => new();
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <returns></returns>
+    public static BadRequestException BadRequest() => new();
+
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <returns></returns>
+    public static ForbiddenException Forbidden() => new();
+}

EnvelopeGenerator.Web/Controllers/Test/TestEnvelopeReceiverController.cs

@@ -6,6 +6,7 @@ using DigitalData.Core.Abstraction.Application.DTO;
 using EnvelopeGenerator.Application.EnvelopeReceivers.Queries;
 using MediatR;
 using EnvelopeGenerator.Application.Extensions;
+using DigitalData.Core.Exceptions;
 
 namespace EnvelopeGenerator.Web.Controllers.Test;
 
@@ -26,7 +27,7 @@ public class TestEnvelopeReceiverController : ControllerBase
 
     [HttpGet]
     public async Task<IActionResult> Get([FromQuery] ReadEnvelopeReceiverQuery q, CancellationToken cancel) 
-        => Ok(await _mediator.Send(q, cancel).ThrowIfNull());
+        => Ok(await _mediator.Send(q, cancel).ThrowIfNull(Exceptions.NotFound));
 
     [Obsolete("Use MediatR")]
     [HttpGet("verify-access-code/{envelope_receiver_id}")]