BuecherwurmAPI/Controllers/CatalogueController.cs

using System.Collections.Generic;
using BuecherwurmAPI.Models;
using Microsoft.AspNetCore.Mvc;

namespace BuecherwurmAPI.Controllers
{
   [Route("katalog") ]
   [ApiController]
   public class KatalogController
   {
        private readonly object _repository;

        /*[HttpGet]
public ActionResult<IEnumerable<Book>> GetAllBooks()
{

}*/

        // GET Katalog/{id}
        [HttpGet("{id}", Name ="GetBookByID")]
        public ActionResult <IEnumerable<Book>> GetBookByID(int id)
        {
            var bookItem = _repository.GetBookByID(id);
            if (bookItem != null)
            {
                return 
            }
        }
   }

}