Simplest Static metatech

static.mjs

import path from 'node:path';
import fs from 'node:fs';
import http from 'node:http';

const HTTP_PORT = 3000;

const STATIC_DIR = path.join(process.cwd(), './static'); 

const fsExists = (filePath) => fs.promises.access(filePath).then(() => true, () => false);

const mimeTypes = {
  default: 'application/octet-stream',
  txt	 : 'text/plain',
  json	 : 'application/json',
  html	 : 'text/html',
  jpe    : 'image/jpeg',
  jpeg	 : 'image/jpeg',
  jpg	 : 'image/jpeg',
  png	 : 'image/png',
  css	 : 'text/css',
};

const getFile = async (url) => {
   const pathParts = [STATIC_DIR, url];
   if (url === '/') pathParts.push('index.html');
   const filePath = path.join(...pathParts);
   const pathTraversal = !filePath.startsWith(STATIC_DIR);
   const found = !pathTraversal && await fsExists(filePath);
   const streamPath = found ? filePath : path.join(STATIC_DIR, '404.html');
   const stream = fs.createReadStream(streamPath);
   const ext = path.extname(streamPath).substring(1).toLowerCase();
   
   return { found, ext, stream };
}

const server = http.createServer(async (req, res) => {
  const { method, url } = req;
  const file = await getFile(req.url);
  const statusCode = file.found ? 200 : 404;
  const mimeType = mimeTypes[file.ext] || mimeTypes.default;
  res.writeHead(statusCode, { 'Content-Type': mimeType });
  file.stream.pipe(res);
  console.log(`request finished: ${method}:${url}`);
});

server.listen(HTTP_PORT);

server.on('listening', () => console.log(`Server started on ${HTTP_PORT}`));