app.js

var createError = require('http-errors');
var express = require('express');
var path = require('path');
var cookieParser = require('cookie-parser');
var logger = require('morgan');
var hbs = require('hbs');
var cors = require("cors");
var rateLimit = require('express-rate-limit');

var indexRouter = require('./routes/index');
var apiRouter = require('./routes/api');

var app = express();

// view engine setup
app.set('views', path.join(__dirname, 'views'));
app.set('view engine', 'hbs');
hbs.registerPartials(__dirname + '/views/partials');
hbs.registerHelper('lowerCase', function (string) {
  return string.toLowerCase();
});

app.use(logger('dev'));
app.use(express.json());
app.use(express.urlencoded({ extended: false }));
app.use(cookieParser());
app.use(express.static(path.join(__dirname, 'public')));

// enable cors
app.use(cors());

// add rate limiter to public apis
const apiRateLimiter = rateLimit({
  windowMs: 1 * 60 * 1000, // 1 minute
  max: 100, // limit each IP to 100 requests per windowMs
  handler: function (req, res, next) {
    return res.status(429).json({
      error: 'You have sent too many requests. Please wait a while then try again.'
    });
  }
});

app.use('/', indexRouter);
app.use('/api', apiRateLimiter, apiRouter);

// catch 404 and forward to error handler
app.use(function (req, res, next) {
  next(createError(404));
});

// error handler
app.use(function (err, req, res, next) {
  // set locals, only providing error in development
  res.locals.message = err.message;
  res.locals.error = req.app.get('env') === 'development' ? err : {};
  // render the error page
  res.status(err.status || 500);
  res.render('error');
});

module.exports = app;