Gist for Medium Article - ColorsController

ColorsController.cs

public class ColorsController : KesselRunApiController
{
        public ColorsController(
            ICurrentUser currentUser,
            ILogger logger,
            IMediator mediator)
            : base(currentUser, logger, mediator){}

        public async Task<IActionResult> GetColors()
        {
            var colors = await _mediator.Send(new GetColorsQuery());

            return colors.Match(
                result => OkResponse(colors.LeftOrDefault()), 
                error => BadRequestResponse(string.Empty, OperationOutcome.ValidationFailOutcome(colors.RightOrDefault().Errors.Select(e => e.ErrorMessage)))                
                );
        }
}