server.mjs

import { createServer } from "node:http";
import { readFile, stat } from "node:fs/promises";
import { extname, join, normalize, resolve } from "node:path";

const root = resolve(".");
const port = Number(process.env.PORT || 4173);

const types = new Map([
  [".html", "text/html; charset=utf-8"],
  [".css", "text/css; charset=utf-8"],
  [".js", "text/javascript; charset=utf-8"],
  [".json", "application/json; charset=utf-8"],
  [".pdf", "application/pdf"],
  [".stl", "model/stl"],
  [".obj", "text/plain; charset=utf-8"],
  [".step", "text/plain; charset=utf-8"],
  [".stp", "text/plain; charset=utf-8"]
]);

function safePath(urlPath) {
  const decoded = decodeURIComponent(urlPath.split("?")[0]);
  const target = normalize(join(root, decoded === "/" ? "index.html" : decoded));
  if (!target.startsWith(root)) {
    return null;
  }
  return target;
}

createServer(async (req, res) => {
  try {
    const target = safePath(req.url || "/");
    if (!target) {
      res.writeHead(403);
      res.end("Forbidden");
      return;
    }

    const info = await stat(target);
    const file = info.isDirectory() ? join(target, "index.html") : target;
    const body = await readFile(file);
    res.writeHead(200, {
      "content-type": types.get(extname(file).toLowerCase()) || "application/octet-stream",
      "cache-control": "no-store"
    });
    res.end(body);
  } catch (error) {
    res.writeHead(error.code === "ENOENT" ? 404 : 500, { "content-type": "text/plain; charset=utf-8" });
    res.end(error.code === "ENOENT" ? "Not found" : `Server error: ${error.message}`);
  }
}).listen(port, () => {
  console.log(`DfM Intelligence Assistant running at http://localhost:${port}`);
});