dbx/docs/scripts/preview-server.mjs

// Local preview for the static export, mimicking Cloudflare Workers asset
// resolution: exact file first, then /foo -> /foo.html, then /foo/ ->
// /foo/index.html, and unknown paths fall back to 404.html like
// not_found_handling: "404-page". Run `pnpm build` before this script.
//
// Usage: node scripts/preview-server.mjs [port]
import { createServer } from "node:http";
import { readFile, stat } from "node:fs/promises";
import { extname, join, resolve } from "node:path";

const ROOT = resolve(import.meta.dirname, "../out");
const PORT = Number(process.argv[2] ?? 3000);
const types = {
  ".html": "text/html; charset=utf-8",
  ".js": "text/javascript",
  ".css": "text/css",
  ".txt": "text/plain",
  ".png": "image/png",
  ".svg": "image/svg+xml",
  ".webp": "image/webp",
  ".json": "application/json",
  ".xml": "application/xml",
  ".ico": "image/x-icon",
  ".map": "application/json",
  ".woff2": "font/woff2",
};

async function tryFile(rel) {
  const file = join(ROOT, rel);
  try {
    const info = await stat(file);
    if (!info.isFile()) return null;
    return { file, type: types[extname(file)] ?? "application/octet-stream" };
  } catch {
    return null;
  }
}

createServer(async (req, res) => {
  try {
    const path = decodeURIComponent(new URL(req.url, "http://localhost").pathname);
    if (path.includes("..")) {
      res.writeHead(400);
      return res.end();
    }
    const hit =
      (await tryFile(path)) ??
      (path.endsWith("/") ? await tryFile(join(path, "index.html")) : await tryFile(`${path}.html`));
    if (hit) {
      res.writeHead(200, { "content-type": hit.type, "cache-control": "no-store" });
      return res.end(await readFile(hit.file));
    }
    const fallback = await tryFile("404.html");
    if (fallback) {
      res.writeHead(404, { "content-type": fallback.type, "cache-control": "no-store" });
      return res.end(await readFile(fallback.file));
    }
    res.writeHead(404, { "content-type": "text/plain" });
    res.end("404");
  } catch (error) {
    res.writeHead(500);
    res.end(String(error));
  }
}).listen(PORT, () => {
  console.log(`Preview serving ${ROOT} at http://localhost:${PORT}`);
});