1960-utils/ReforgerOutputConsole/server.js

// Reforger Output Console
// Watches several log folders, picks the newest subfolder of each and
// streams the log file inside it live to a browser UI.

const http = require('http');
const fs = require('fs');
const path = require('path');
const { spawn } = require('child_process');
const { StringDecoder } = require('string_decoder');

const CONFIG_PATH = path.join(__dirname, 'config.json');
const INDEX_PATH = path.join(__dirname, 'index.html');

const config = JSON.parse(fs.readFileSync(CONFIG_PATH, 'utf8'));
const PORT = config.port || 8420;
const POLL_MS = config.pollIntervalMs || 500;
const MAX_LINES = config.maxLinesPerPane || 20000;
// Server-side buffer so newly connected browsers receive the existing content.
const MAX_CHARS = MAX_LINES * 300;
const CRASH_FILE = config.crashFile || 'crash.log';

const panes = config.panes.map((p, i) => ({
  id: i,
  name: p.name || path.basename(path.dirname(p.logsDir)),
  logsDir: path.resolve(__dirname, p.logsDir),
  file: p.file || 'console.log',
  folder: undefined,
  offset: 0,
  decoder: new StringDecoder('utf8'),
  text: '',
  dirMissing: false,
  crash: null,
  crashStamp: '',
}));

const clients = new Set();

function broadcast(event, data) {
  const msg = `event: ${event}\ndata: ${JSON.stringify(data)}\n\n`;
  for (const res of clients) res.write(msg);
}

function snapshot(p) {
  return {
    id: p.id,
    name: p.name,
    file: p.file,
    folder: p.folder || null,
    logsDir: p.logsDir,
    dirMissing: p.dirMissing,
    text: p.text,
    crash: p.crash,
  };
}

// Newest subfolder by creation time (ties broken by name).
function newestFolder(dir) {
  let entries;
  try {
    entries = fs.readdirSync(dir, { withFileTypes: true });
  } catch {
    return undefined;
  }
  let best = null;
  let bestTime = -Infinity;
  for (const e of entries) {
    if (!e.isDirectory()) continue;
    let t;
    try {
      t = fs.statSync(path.join(dir, e.name)).birthtimeMs;
    } catch {
      continue;
    }
    if (t > bestTime || (t === bestTime && e.name > best)) {
      best = e.name;
      bestTime = t;
    }
  }
  return best;
}

function resetPane(p) {
  p.offset = 0;
  p.decoder = new StringDecoder('utf8');
  p.text = '';
  p.crash = null;
  p.crashStamp = '';
  broadcast('reset', snapshot(p));
}

// The crash report is small and is resent in full on every change.
function pollCrash(p) {
  const file = path.join(p.logsDir, p.folder, CRASH_FILE);
  let st;
  try {
    st = fs.statSync(file);
  } catch {
    return;
  }
  const stamp = `${st.size}:${st.mtimeMs}`;
  if (stamp === p.crashStamp) return;
  let text;
  try {
    text = fs.readFileSync(file, 'utf8');
  } catch {
    return;
  }
  if (p.crash === null) console.log(`[${p.name}] Crash report found: ${p.folder}\\${CRASH_FILE}`);
  p.crashStamp = stamp;
  p.crash = text;
  broadcast('crash', { id: p.id, text });
}

function pollPane(p) {
  const folder = newestFolder(p.logsDir);
  const dirMissing = folder === undefined;
  if (folder !== p.folder || dirMissing !== p.dirMissing) {
    if (p.folder !== undefined && folder) {
      console.log(`[${p.name}] New log folder: ${folder}`);
    }
    p.folder = folder;
    p.dirMissing = dirMissing;
    resetPane(p);
  }
  if (!folder) return;

  pollCrash(p);

  const file = path.join(p.logsDir, folder, p.file);
  let size;
  try {
    size = fs.statSync(file).size;
  } catch {
    return; // file doesn't exist (yet)
  }

  if (size < p.offset) resetPane(p); // file was truncated/rewritten
  if (size === p.offset) return;

  let start = p.offset;
  if (size - start > MAX_CHARS) start = size - MAX_CHARS;
  const len = size - start;
  const buf = Buffer.alloc(len);
  let fd;
  try {
    fd = fs.openSync(file, 'r');
    fs.readSync(fd, buf, 0, len, start);
  } catch {
    return;
  } finally {
    if (fd !== undefined) fs.closeSync(fd);
  }
  p.offset = size;

  const chunk = p.decoder.write(buf);
  if (!chunk) return;
  p.text += chunk;
  if (p.text.length > MAX_CHARS) {
    const cut = p.text.indexOf('\n', p.text.length - MAX_CHARS);
    p.text = p.text.slice(cut + 1);
  }
  broadcast('append', { id: p.id, chunk });
}

function pollAll() {
  for (const p of panes) {
    try {
      pollPane(p);
    } catch (err) {
      console.error(`[${p.name}]`, err.message);
    }
  }
}

const server = http.createServer((req, res) => {
  const url = new URL(req.url, `http://${req.headers.host}`);

  if (url.pathname === '/') {
    res.writeHead(200, { 'Content-Type': 'text/html; charset=utf-8' });
    fs.createReadStream(INDEX_PATH).pipe(res);
    return;
  }

  if (url.pathname === '/events') {
    res.writeHead(200, {
      'Content-Type': 'text/event-stream',
      'Cache-Control': 'no-cache',
      Connection: 'keep-alive',
    });
    res.write(`event: init\ndata: ${JSON.stringify({ maxLines: MAX_LINES, panes: panes.map(snapshot) })}\n\n`);
    clients.add(res);
    req.on('close', () => clients.delete(res));
    return;
  }

  // Opens a pane's current log folder in Explorer.
  if (url.pathname === '/open' && req.method === 'POST') {
    const p = panes[Number(url.searchParams.get('id'))];
    if (p) {
      const dir = p.folder ? path.join(p.logsDir, p.folder) : p.logsDir;
      spawn('explorer', [dir], { detached: true, stdio: 'ignore' }).unref();
    }
    res.writeHead(204).end();
    return;
  }

  res.writeHead(404).end();
});

// Keep-alive so connections aren't closed due to inactivity.
setInterval(() => {
  for (const res of clients) res.write(': ping\n\n');
}, 15000);

server.listen(PORT, '127.0.0.1', () => {
  const url = `http://localhost:${PORT}`;
  console.log(`Reforger Output Console running at ${url}`);
  for (const p of panes) console.log(`  - ${p.name}: ${p.logsDir}\\<newest folder>\\${p.file}`);
  console.log('Press Ctrl+C to stop.');
  pollAll();
  setInterval(pollAll, POLL_MS);
  if (config.openBrowser !== false) {
    spawn('cmd', ['/c', 'start', '', url], { detached: true, stdio: 'ignore' }).unref();
  }
});

server.on('error', (err) => {
  if (err.code === 'EADDRINUSE') {
    console.error(`Port ${PORT} is already in use – is the console already running? Otherwise change "port" in config.json.`);
  } else {
    console.error(err);
  }
  process.exit(1);
});