Ein Stück vom Kuchen

using MediatR;
using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.Mvc;
using TodosVertical.Common;

namespace TodosVertical.Features.UpdateTodoItem;

[Authorize]
public class TodoItemsController : ApiControllerBase
{
  [HttpPut("{id}")]
  public async Task<ActionResult> Update(
    int id,
    UpdateTodoItemCommand command
  )
  {
    if (id != command.Id)
    {
      return BadRequest();
    }

    await Mediator.Send(command);

    return NoContent();
  }
}

public record UpdateTodoItemCommand : IRequest
{
  public int Id { get; init; }

  public string? Title { get; init; }

  public bool Done { get; init; }
}

public class UpdateTodoItemCommandHandler :
    IRequestHandler<UpdateTodoItemCommand>
{
  private readonly IApplicationDbContext _context;

  public UpdateTodoItemCommandHandler(
    IApplicationDbContext context
  )
  {
    _context = context;
  }

  public async Task<Unit> Handle(
    UpdateTodoItemCommand request,
    CancellationToken cancellationToken
  )
  {
    var entity = await _context.TodoItems
      .FindAsync(new object[] { request.Id },
      cancellationToken);

    if (entity == null)
    {
      throw new NotFoundException(nameof(TodoItem),
        request.Id);
    }

    entity.Title = request.Title;
    entity.Done = request.Done;

    await _context.SaveChangesAsync(
      cancellationToken);

    return Unit.Value;
  }
}

public class TodoItemCompletedEvent : BaseEvent
{
  public TodoItemCompletedEvent(
    TodoItem item
  )
  {
    Item = item;
  }

  public TodoItem Item { get; }
}

public class FeatureFolderLocationExpander :
  IViewLocationExpander
{
  public void PopulateValues(
    ViewLocationExpanderContext context
  )
  {
  }

  public IEnumerable<string> ExpandViewLocations(
    ViewLocationExpanderContext context,
    IEnumerable<string> viewLocations
  )
  {
    return new[]
    {
      "~/Features/{1}/{0}.cshtml"
    };
  }
}