2chBackAPI/Controllers/ShowThreads.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 ThreadsController : ControllerBase
    {
        [HttpGet(Name = "GetThreads")]
        public string Get([FromUri] string board)
        {
           string postsJson = JsonSerializer.Serialize(APIThreadBuffer.GetOPPosts());
           return postsJson;
        }
    }
}