app.js

const express = require('express');
const expressLayouts = require('express-ejs-layouts');
const mongoose = require('mongoose');
const passport = require('passport');
const flash = require('connect-flash');
const session = require('express-session');
var serveStatic = require('serve-static') //for serving static 
const path = require('path');

const app = express();
// serve static files from public folder

app.use(serveStatic(path.join(__dirname, 'public'), {
    maxAge: '1d',
    setHeaders: setCustomCacheControl
  }))
  function setCustomCacheControl (res, path) {
    if (serveStatic.mime.lookup(path) === 'text/html') {
      // Custom Cache-Control for HTML files
      res.setHeader('Cache-Control', 'public, max-age=0')
    }
  }




// Passport Config
require('./config/passport')(passport);

// DB Config
const db = require('./config/keys').mongoURI;

// Connect to MongoDB
mongoose
    .connect(
        db,
        { useNewUrlParser: true }
    )
    .then(() => console.log('MongoDB Connected'))
    .catch(err => console.log(err));

// EJS
app.use(expressLayouts);
app.set('view engine', 'ejs');

// Express body parser
app.use(express.urlencoded({ extended: true }));

// Express session
app.use(
    session({
        secret: 'secret',
        resave: true,
        saveUninitialized: true
    })
);

// Passport middleware
app.use(passport.initialize());
app.use(passport.session());

// Connect flash
app.use(flash());

// Global variables
app.use(function (req, res, next) {
    res.locals.success_msg = req.flash('success_msg');
    res.locals.error_msg = req.flash('error_msg');
    res.locals.error = req.flash('error');
    next();
});

// Routes
app.use('/', require('./routes/index.js'));
app.use('/users', require('./routes/users.js'));

const PORT = process.env.PORT || 3000;

app.listen(PORT, console.log(`Server started on port ${PORT}`));