server.js

const http = require("node:http");
const fs = require("node:fs/promises");
const path = require("node:path");

const HOST = process.env.HOST || "127.0.0.1";
const PORT = Number(process.env.PORT || 4173);
const ROOT = __dirname;

const CONTENT_TYPES = {
  ".css": "text/css; charset=utf-8",
  ".csv": "text/csv; charset=utf-8",
  ".html": "text/html; charset=utf-8",
  ".ico": "image/x-icon",
  ".js": "text/javascript; charset=utf-8",
  ".json": "application/json; charset=utf-8",
  ".png": "image/png",
  ".svg": "image/svg+xml; charset=utf-8",
};

function resolvePath(urlPath) {
  const pathname = decodeURIComponent(urlPath.split("?")[0]);
  const target = pathname === "/" ? "/index.html" : pathname;
  const absolutePath = path.normalize(path.join(ROOT, target));

  if (!absolutePath.startsWith(ROOT)) {
    return null;
  }

  return absolutePath;
}

async function serveFile(filePath, response) {
  const extension = path.extname(filePath).toLowerCase();
  const contentType = CONTENT_TYPES[extension] || "application/octet-stream";
  const file = await fs.readFile(filePath);

  response.writeHead(200, { "content-type": contentType });
  response.end(file);
}

const server = http.createServer(async (request, response) => {
  const filePath = resolvePath(request.url || "/");

  if (!filePath) {
    response.writeHead(403, { "content-type": "text/plain; charset=utf-8" });
    response.end("Forbidden");
    return;
  }

  try {
    const stats = await fs.stat(filePath);
    if (stats.isDirectory()) {
      await serveFile(path.join(filePath, "index.html"), response);
      return;
    }

    await serveFile(filePath, response);
  } catch {
    response.writeHead(404, { "content-type": "text/plain; charset=utf-8" });
    response.end("Not found");
  }
});

server.listen(PORT, HOST, () => {
  console.log(`Serving http://${HOST}:${PORT}`);
});