public async Task <IActionResult> Post([FromBody] BookCreateRequestModel book) { if (!await authorService.AuthorExistsAsync(book.AuthorId)) { return(BadRequest("Author does not exist.")); } int bookId = await bookService.CreateBookAsync(book.Title, book.Description, book.Price, book.Copies, book.Edition, book.AuthorId, book.Categories); return(this.Ok(bookId)); }