Body Parsing

// Parse application/json
app.use(express.json());

// Parse application/x-www-form-urlencoded (HTML forms)
app.use(express.urlencoded({ extended: true }));

// Parse raw Buffer body
app.use(express.raw({ type: 'application/octet-stream' }));

// Parse plain text body
app.use(express.text({ type: 'text/plain' }));

app.use(express.json({
  limit:    '100kb',       // max body size (default '100kb')
  strict:   true,          // only accept arrays and objects (default true)
  type:     'application/json', // MIME types to parse (string, array, or function)
  reviver:  null,          // JSON.parse reviver function
  inflate:  true,          // handle deflated/gzip bodies
}));

// Accept multiple content types
app.use(express.json({ type: ['application/json', 'application/cjson'] }));

// Custom reviver — convert ISO date strings to Date objects
app.use(express.json({
  reviver: (key, value) => {
    if (typeof value === 'string' && /^\d{4}-\d{2}-\d{2}T/.test(value))
      return new Date(value);
    return value;
  }
}));

app.use(express.urlencoded({
  extended: true,    // true = qs (nested objects); false = querystring (flat)
  limit:    '100kb',
  parameterLimit: 1000,  // max number of parameters (default 1000)
  type: 'application/x-www-form-urlencoded',
}));

// Form: filter[price][gte]=10&filter[price][lte]=100
req.body.filter.price.gte // '10'

// filter[price][gte]=10 → req.body['filter[price][gte]'] = '10'

app.use(express.raw({
  type:   'application/octet-stream',
  limit:  '10mb',
  inflate: true,
}));

app.post('/upload', (req, res) => {
  req.body; // Buffer
  req.body.length; // byte count
});

app.use(express.text({
  type:         'text/plain',
  defaultCharset: 'utf-8',
  limit:        '100kb',
}));

app.post('/webhook', (req, res) => {
  typeof req.body; // 'string'
});

// High limit only for file endpoint
app.post('/import', express.json({ limit: '10mb' }), (req, res) => {
  // large JSON allowed here only
});

// Raw body for Stripe webhook (must NOT go through express.json first)
app.post(
  '/webhook',
  express.raw({ type: 'application/json' }),
  (req, res) => {
    const sig  = req.headers['stripe-signature'];
    const event = stripe.webhooks.constructEvent(req.body, sig, process.env.STRIPE_SECRET);
    // req.body is a Buffer here
  }
);

// JSON everywhere else
app.use(express.json());

const multer = require('multer');

// Memory storage (file in req.file.buffer)
const upload = multer({ storage: multer.memoryStorage(), limits: { fileSize: 5 * 1024 * 1024 } });

// Disk storage
const disk = multer.diskStorage({
  destination: (req, file, cb) => cb(null, './uploads'),
  filename:    (req, file, cb) => cb(null, `${Date.now()}-${file.originalname}`),
});
const uploadDisk = multer({ storage: disk });

// Single file
router.post('/avatar', upload.single('avatar'), (req, res) => {
  req.file;    // { fieldname, originalname, mimetype, buffer, size }
  req.body;    // other form fields
});

// Multiple files, same field
router.post('/photos', upload.array('photos', 5), (req, res) => {
  req.files; // array
});

// Multiple fields
router.post('/form', upload.fields([
  { name: 'avatar', maxCount: 1 },
  { name: 'gallery', maxCount: 10 },
]), (req, res) => {
  req.files.avatar[0];    // single avatar file
  req.files.gallery;      // array
});

// No file — just multipart form fields
router.post('/form', upload.none(), (req, res) => {
  req.body; // parsed fields
});

const upload = multer({
  fileFilter: (req, file, cb) => {
    const allowed = ['image/jpeg', 'image/png', 'image/webp'];
    if (!allowed.includes(file.mimetype)) {
      return cb(new Error('Only JPEG, PNG, and WebP allowed'));
    }
    cb(null, true);
  },
  limits: { fileSize: 2 * 1024 * 1024 }, // 2 MB
});

app.post('/data', express.json(), (req, res) => {
  if (!req.body || Object.keys(req.body).length === 0) {
    return res.status(400).json({ error: 'Empty body' });
  }
  // ...
});

app.use((err, req, res, next) => {
  if (err.type === 'entity.too.large') {
    return res.status(413).json({ error: 'Payload too large' });
  }
  next(err);
});

app.post('/data', express.json(), (req, res) => {
  if (req.body === undefined) {
    return res.status(415).json({ error: 'Unsupported Media Type' });
  }
});