Refactor controllers for MediatR and cleaner API design

- Switch EnvelopeController and ReceiverController to MediatR for all operations
- Encapsulate UserId in CreateEnvelopeCommand via Authorize() method
- Change CreateEnvelopeCommand binding to [FromBody]
- Add CancellationToken support to EnvelopeReceiverController
- Remove obsolete CRUD logic from ReceiverController; now only supports GET via MediatR
- Clean up unused dependencies and update controller summaries for clarity

EnvelopeGenerator.GeneratorAPI/Controllers/ReceiverController.cs

@@ -1,12 +1,7 @@
-using DigitalData.Core.Abstraction.Application.DTO;
-using DigitalData.Core.API;
+using MediatR;
 using EnvelopeGenerator.Application.Receivers.Queries;
-using EnvelopeGenerator.Domain.Entities;
 using Microsoft.AspNetCore.Authorization;
 using Microsoft.AspNetCore.Mvc;
-using EnvelopeGenerator.Application.Receivers.Commands;
-using EnvelopeGenerator.Application.Common.Dto.Receiver;
-using EnvelopeGenerator.Application.Common.Interfaces.Services;
 
 namespace EnvelopeGenerator.GeneratorAPI.Controllers;
 
@@ -14,22 +9,22 @@ namespace EnvelopeGenerator.GeneratorAPI.Controllers;
 /// Controller für die Verwaltung von Empfängern.
 /// </summary>
 /// <remarks>
-/// Dieser Controller bietet Endpunkte für CRUD-Operationen (Erstellen, Lesen, Aktualisieren, Löschen) 
-/// sowie zusätzliche Funktionen wie das Abrufen von Empfängern basierend auf E-Mail-Adresse oder Signatur.
+/// Dieser Controller bietet Endpunkte für das Abrufen von Empfängern basierend auf E-Mail-Adresse oder Signatur.
 /// </remarks>
 [Route("api/[controller]")]
 [ApiController]
 [Authorize]
-[Obsolete("Use MediatR")]
-public class ReceiverController : CRUDControllerBaseWithErrorHandling<IReceiverService, CreateReceiverCommand, ReceiverDto, UpdateReceiverCommand, Receiver, int>
+public class ReceiverController : ControllerBase
 {
+    private readonly IMediator _mediator;
+
     /// <summary>
     /// Initialisiert eine neue Instanz des <see cref="ReceiverController"/>-Controllers.
     /// </summary>
-    /// <param name="logger">Der Logger für die Protokollierung.</param>
-    /// <param name="service">Der Dienst für Empfängeroperationen.</param>
-    public ReceiverController(ILogger<ReceiverController> logger, IReceiverService service) : base(logger, service)
+    /// <param name="mediator">Mediator für Anfragen.</param>
+    public ReceiverController(IMediator mediator)
     {
+        _mediator = mediator;
     }
 
     /// <summary>
@@ -40,60 +35,13 @@ public class ReceiverController : CRUDControllerBaseWithErrorHandling<IReceiverS
     [HttpGet]
     public async Task<IActionResult> Get([FromQuery] ReadReceiverQuery receiver)
     {
-        if (receiver.Id is null && receiver.EmailAddress is null && receiver.Signature is null)
-            return await base.GetAll();
+        if (!receiver.HasAnyCriteria)
+        {
+            var all = await _mediator.Send(new ReadReceiverQuery());
+            return Ok(all);
+        }
 
-        if (receiver.Id is int id)
-            return await _service.ReadByIdAsync(id).ThenAsync(
-                Success: Ok,
-                Fail: IActionResult (msg, ntc) =>
-                {
-                    return NotFound();
-                });
-
-        return await _service.ReadByAsync(emailAddress: receiver.EmailAddress, signature: receiver.Signature).ThenAsync(
-                Success: Ok,
-                Fail: IActionResult (msg, ntc) =>
-                {
-                    return NotFound();
-                });
+        var result = await _mediator.Send(receiver);
+        return result is null ? NotFound() : Ok(result);
     }
-
-    #region REMOVED ENDPOINTS
-    /// <summary>
-    /// Diese Methode ist deaktiviert und wird nicht verwendet.
-    /// </summary>
-    [NonAction]
-    public override Task<IActionResult> GetAll() => base.GetAll();
-
-    /// <summary>
-    /// Diese Methode ist deaktiviert und wird nicht verwendet.
-    /// </summary>
-    [NonAction]
-    public override Task<IActionResult> Delete([FromRoute] int id) => base.Delete(id);
-
-    /// <summary>
-    /// Diese Methode ist deaktiviert und wird nicht verwendet.
-    /// </summary>
-    [NonAction]
-    public override Task<IActionResult> Update(UpdateReceiverCommand updateDto) => base.Update(updateDto);
-
-    /// <summary>
-    /// Diese Methode ist deaktiviert und wird nicht verwendet.
-    /// </summary>
-    [NonAction]
-    public override Task<IActionResult> Create(CreateReceiverCommand createDto)
-    {
-        return base.Create(createDto);
-    }
-
-    /// <summary>
-    /// Diese Methode ist deaktiviert und wird nicht verwendet.
-    /// </summary>
-    [NonAction]
-    public override Task<IActionResult> GetById([FromRoute] int id)
-    {
-        return base.GetById(id);
-    }
-    #endregion
 }