2chBackAPI/Controllers/GetPosts.cs

using Microsoft.AspNetCore.Mvc;
using System.Text.Json;
using System.Web.Http;
using HttpGetAttribute = Microsoft.AspNetCore.Mvc.HttpGetAttribute;
using RouteAttribute = Microsoft.AspNetCore.Mvc.RouteAttribute;

namespace NeDvachAPI.Controllers
{
    [ApiController]
    [Route("[controller]")]
    public class ListController : ControllerBase
    {
        [HttpGet(Name = "GetPosts")]
        public string Get([FromUri] string board, int thread)
        { 
            List<Post> posts  = DBchat.DbList(board, thread);
            string postsJson = JsonSerializer.Serialize(posts);
            Console.WriteLine("Запрошен список постов из борды " + board + " и треда# " + thread );
            return postsJson ;
        }
    }
}