server.js

// server.js – write-access tester
import express from 'express';
import fs       from 'fs';
import fsp      from 'fs/promises';
import path     from 'path';

const PORT = process.env.PORT || 7860;
const DIR  = '/data';                     // Space-persistent volume
const FILE = path.join(DIR, 'test.txt');

const app  = express();
app.use(express.json());

/* POST /write  -> attempts three save methods */
app.post('/write', async (_req, res) => {
  const report = {};

  // ensure /data exists
  try {
    fs.mkdirSync(DIR, { recursive: true });
    report.mkdir = 'ok';
  } catch (e) {
    report.mkdir = e.message;
  }

  /* ---- Method A: sync write ---- */
  try {
    fs.writeFileSync(FILE, 'sync write\n', { flag: 'a' });
    report.sync = 'ok';
  } catch (e) {
    report.sync = e.message;
  }

  /* ---- Method B: fs.promises ---- */
  try {
    await fsp.writeFile(FILE, 'promises write\n', { flag: 'a' });
    report.promise = 'ok';
  } catch (e) {
    report.promise = e.message;
  }

  /* ---- Method C: stream ---- */
  try {
    await new Promise((resolve, reject) => {
      const stream = fs.createWriteStream(FILE, { flags: 'a' });
      stream.on('error', reject);
      stream.end('stream write\n', resolve);
    });
    report.stream = 'ok';
  } catch (e) {
    report.stream = e.message;
  }

  res.json(report);
});

/* GET /read  -> returns file contents or error */
app.get('/read', (req, res) => {
  try {
    const txt = fs.readFileSync(FILE, 'utf-8');
    res.type('text/plain').send(txt);
  } catch (e) {
    res.status(500).send(e.message);
  }
});

app.listen(PORT, '0.0.0.0', () =>
  console.log(`📝 Write-test server listening on ${PORT} (DIR=${DIR})`)
);