Super simple c# file server - works with https://www.cs-script.net/

SimplestHttpFileServer.cs

using System;
using System.IO;
using System.Text;
using System.Threading.Tasks;
using System.Net;

namespace SimplestHttpFileServer
{

    class Program
    {
        static void Main(string[] args)
        {
            HttpListener server = new HttpListener();
            server.Prefixes.Add("http://localhost:8080/");
            server.Start();

            Console.WriteLine("Server started ...");

            while (true)
            {
                HttpListenerContext context = server.GetContext();

                Task.Run( async () => {
                    HttpListenerResponse response = context.Response;
                    HttpListenerRequest request = context.Request;

                    //test parallel calls :  await Task.Delay(TimeSpan.FromSeconds(5));

                    string pagePath = Directory.GetCurrentDirectory() + (request.Url.LocalPath == "/" ? @"\index.html" : request.Url.LocalPath);
                    string html = "";

                    try {
                        // pagePath seems to be resolved dynamically - no need for any traversal stuff (`/../` or `/./`)
                        html = new StreamReader(pagePath).ReadToEnd();

                        Console.WriteLine("200 " + request.HttpMethod + " " + request.Url.LocalPath);
                    }
                    catch(Exception ex) {
                        if (ex is System.IO.FileNotFoundException || ex is System.IO.DirectoryNotFoundException) {
                            response.StatusCode = (int)HttpStatusCode.NotFound;
                            response.StatusDescription = "404";
                            html = "Not found";

                            Console.WriteLine("404 " + request.HttpMethod + " " + request.Url.LocalPath);
                        }
                        else {
                            response.StatusCode = (int) HttpStatusCode.InternalServerError;
                            response.StatusDescription = "500";
                            html = "Internal Server Error: " + ex.Message;

                            Console.WriteLine("500 " + request.HttpMethod + " " + request.Url.LocalPath + " --(" + ex.Message + ")");
                        }
                    }

                    byte[] buffer = Encoding.UTF8.GetBytes(html);
                    response.ContentLength64 = buffer.Length;
                    response.OutputStream.Write(buffer, 0, buffer.Length);

                    response.Close();
                
                });

            }

        }
    }

}