How to use express

router.post('/books/add', async (req, res) => {
 try {
  const book = await Book.add(Object.assign({ userId: req.user.id }, req.body));
  res.json(book);
 } catch (err) {
  logger.error(err);
  res.json({ error: err.message || err.toString() });
 }
});

router.use((req, res, next) => {
 if (!req.user || !req.user.isAdmin) {
  res.status(401).json({ error: 'Unauthorized' });
  return;
 }

 next();
});

router.get('/books', async (req, res) => {
 try {
  const books = await Book.list();
  res.json(books);
 } catch (err) {
  res.json({ error: err.message || err.toString() });
 }
});

// Start listening
Promise.fromNode(cb => {
 api.listen(config.LANDO_API_PORT, cb);
})
// Load our routes
.then(() => {
 fs.readdirSync(path.join(__dirname, 'routes')).map(file => {
  require(`./routes/${file}`)(api, handler, {config, slack});
  log.info('Loaded route %s', file);
 });
 log.info('Listening on port: %s', config.LANDO_API_PORT);
});

router.post('/torrents/delete', (req, res) => {
 const {deleteData, hash: hashes} = req.body;
 const callback = ajaxUtil.getResponseFn(res);

 req.services.clientGatewayService
  .removeTorrents({hashes, deleteData})
  .then(callback)
  .catch(err => {
   callback(null, err);
  });
});

app.use(serveStatic(path.join(__dirname, '../playground'), {
   lastModified: false,
   etag: false,
   setHeaders: (res, url) => {
    if (url.indexOf('/index.html') !== -1) {
     res.setHeader('Cache-Control', 'no-cache');
    }
   }
  }));

// Rooms
router.get('/rooms', [User.isAuthenticated, function(req, res, next) {
  Room.find(function(err, rooms){
    if(err) throw err;
    res.render('rooms', { rooms });
  });
}]);

// Main logix
Promise.fromNode(cb => {
 api.listen(config.LANDO_METRICS_PORT, cb);
})
.then(() => {
 log.info('Listening on port: %s', config.LANDO_METRICS_PORT);
});

router.get('/books/detail/:slug', async (req, res) => {
 try {
  const book = await Book.getBySlug({ slug: req.params.slug });
  res.json(book);
 } catch (err) {
  res.json({ error: err.message || err.toString() });
 }
});

// Basic HTTP response
app.get('/', (req, res) => {
 res.header('Content-type', 'text/html');
 return res.end('<h1>DANCING DANCING STARLIGHT</h1>');
});

router.get('/books', async (req, res) => {
 try {
  const books = await Book.list();
  res.json(books);
 } catch (err) {
  res.json({ error: err.message || err.toString() });
 }
});

router.post('/books/add', async (req, res) => {
 try {
  const book = await Book.add(Object.assign({ userId: req.user.id }, req.body));
  res.json(book);
 } catch (err) {
  logger.error(err);
  res.json({ error: err.message || err.toString() });
 }
});

router.get('/books', async (req, res) => {
 try {
  const books = await Book.list();
  res.json(books);
 } catch (err) {
  res.json({ error: err.message || err.toString() });
 }
});

router.post('/books/add', async (req, res) => {
 try {
  const book = await Book.add(Object.assign({ userId: req.user.id }, req.body));
  res.json(book);
 } catch (err) {
  logger.error(err);
  res.json({ error: err.message || err.toString() });
 }
});

router.get('/books/detail/:slug', async (req, res) => {
 try {
  const book = await Book.getBySlug({ slug: req.params.slug });
  res.json(book);
 } catch (err) {
  res.json({ error: err.message || err.toString() });
 }
});