server.js HTML cache never invalidates when files change on disk

[rishab11250]

Description

The serveHtml() function (server.js:83-97) caches HTML file contents in the htmlCache object indefinitely on first read. If any .html file is modified after the server starts, the cache returns stale content until the process is restarted.

This is especially problematic during development — edits to leaderboard.html, user.html, etc. require a manual server restart to take effect.

Affected Code

const htmlCache = {};
function serveHtml(res, filePath) {
  if (htmlCache[filePath]) {
    const html = htmlCache[filePath].replace(/__NONCE__/g, res.locals.nonce);
    return res.type("html").send(html);  // ← always returns cached version
  }

  fs.readFile(filePath, "utf8", (err, data) => {
    if (err) return res.status(500).send("Error loading page");
    htmlCache[filePath] = data;  // ← never invalidated
    const html = data.replace(/__NONCE__/g, res.locals.nonce);
    res.type("html").send(html);
  });
}

Steps to Reproduce

1. Start the server (npm run dev)
2. Edit frontend/leaderboard.html (add a test comment)
3. Refresh http://localhost:3000/leaderboard
4. The change does not appear — old cached version is served
5. Restart the server — change now appears

Expected Behavior

File changes should be reflected without a server restart during development. The cache should either use mtime validation, or be disabled when NODE_ENV=development.

Suggested Fix

Option A — Check file modification time on each request:

const htmlCache = {};  // { filePath: { mtime: Date, data: string } }

function serveHtml(res, filePath) {
  fs.stat(filePath, (err, stats) => {
    if (err) return res.status(500).send("Error loading page");
    const cached = htmlCache[filePath];
    if (cached && cached.mtime >= stats.mtimeMs) {
      return res.type("html").send(cached.data.replace(/__NONCE__/g, res.locals.nonce));
    }
    fs.readFile(filePath, "utf8", (readErr, data) => {
      if (readErr) return res.status(500).send("Error loading page");
      htmlCache[filePath] = { mtime: stats.mtimeMs, data };
      res.type("html").send(data.replace(/__NONCE__/g, res.locals.nonce));
    });
  });
}

Option B — Skip cache entirely when process.env.NODE_ENV === 'development'.

Affected Files

• server.js (lines 83-97)

[github-actions]

Thank you for opening an issue.

Please review our CONTRIBUTING.md guidelines before getting started.

A maintainer will review this issue shortly. If you would like to work on the issue yourself, please leave a comment requesting assignment.

Issue Assignment Policy

• The issue creator is given the first priority to work on their issue.
• If the creator declines or does not request assignment, the issue will be assigned to others in the order of requests received.
• Please do not submit PRs or begin work until you are officially assigned.

Note: This project is currently maintained by a solo maintainer, so reviews, assignments, and responses may sometimes take a little time. Thanks for your patience.

[rishab11250]

I want to work on this