No-dependency HTTP Server in node.js

http-server.js

import fs from "node:fs";
import http from "node:http";
import path from "node:path";
import process from "node:process";

const PORT = 8000;
const STATIC_PATH = path.join(process.cwd(), "./static");
const NOT_FOUND_HTML_PATH = path.join(STATIC_PATH, "./404.html");

const MIDDLEWARE_HANDLER = async (req, res) => {
  const filePath = (url.endsWith("/") ? [STATIC_PATH, url, "index.html"] : [STATIC_PATH, url]).join('');
  const statusCode = await fileExists(filePath) ? 200 : 404;

  console.log(`${req.method} ${req.url} ${statusCode}`);
};
const NOT_FOUND_HTML_HANDLER = async (req, res) => {
  res.writeHead(404, {
    "Content-Type": MIME_TYPES.html
  });
  fs.createReadStream(NOT_FOUND_HTML_PATH).pipe(res);
};

const MIME_TYPES = {
  default: "application/octet-stream",
  html: "text/html; charset=UTF-8",
  js: "application/javascript",
  css: "text/css",
  png: "image/png",
  jpg: "image/jpg",
  gif: "image/gif",
  ico: "image/x-icon",
  svg: "image/svg+xml",
};

async function fileExists(pathString) {
  return await fs.promises.access(pathString).then(() => true, () => false)
}

function createHTTPServer(port, handler) {
  return new Promise((resolve, reject) => {
    let server = http.createServer(handler)
      .once('error', reject)
      .on('listening', () => resolve(server))
      .listen(port);
  });
}

await createHTTPServer(PORT, async ({ url, headers, method }, res) => {
  const filePath = (url.endsWith("/") ? [STATIC_PATH, url, "index.html"] : [STATIC_PATH, url]).join('');
  const statusCode = await fileExists(filePath) ? 200 : 404;
  const contentType =
    headers.accept?.includes('text/html')
      ? MIME_TYPES.html
      : MIME_TYPES[path.extname(filePath).substring(1).toLowerCase()] || MIME_TYPES.default;

  res.writeHead(statusCode, { "Content-Type": contentType });

  fs.createReadStream(statusCode === 200 ? filePath : NOT_FOUND_HTML_PATH)
    .pipe(res);

  console.log(`${method} ${url} ${statusCode}`);
});

console.log(`Server running at http://127.0.0.1:${PORT}/`);