public ActionResult <IEnumerable <AuthorDto> > Get([FromRoute] string keys) { if (string.IsNullOrWhiteSpace(keys)) { return(BadRequest()); } var authorIds = keys.Split(','); var authors = _repository.GetAuthorsByIds(authorIds); if (authors.Count() != authorIds.Length) { return(NotFound()); } return(Ok(_mapper.Map <IEnumerable <AuthorDto> >(authors))); }