app.js

if (process.env.NODE_ENV !== "production") {
    require('dotenv').config();
}

const express = require('express');
const mongoose = require('mongoose');
const ejsMate = require('ejs-mate');
const methodOverride = require('method-override');
const path = require('path');
const ExpressError = require('./utils/ExpressError');
const session = require('express-session');
const flash = require('connect-flash');
const passport = require('passport');
const LocalStrategy = require('passport-local');
const User = require('./models/user');
const mongoSanitize = require('express-mongo-sanitize');
const MongoStore = require('connect-mongo');

// importing routes
const userRoutes = require('./routes/users');
const landscapeRoutes = require('./routes/landscapes');
const reviewRoutes = require('./routes/reviews');

const dbUrl = process.env.DB_URL || 'mongodb://localhost:27017/landscapesDB';
const secret = process.env.SECRET || 'ABC'


// mongoose config
mongoose.connect(dbUrl, 
    {
        useNewUrlParser: true,
        useUnifiedTopology: true,
    });

const db = mongoose.connection;
db.on("error", console.error.bind(console, "connection error:"));
db.once("open", () => {
    console.log("Database connected");
});

const app = express();

// middleware

app.engine('ejs', ejsMate)
app.set('view engine', 'ejs');
app.set('views', path.join(__dirname, 'views'))

app.use(express.urlencoded({ extended: true }));
app.use(methodOverride('_method'));
app.use(express.static(path.join(__dirname, 'public')))

//sanitizing queries, replacing volnerability with '_' 
app.use(mongoSanitize({
    replaceWith: '_'
}))

const store = MongoStore.create({
    mongoUrl: dbUrl,
    secret: secret,
    touchAfter: 24 * 60 * 60
})

store.on('error', function(e) {
    console.log('Session Store Error', e)
})

// session config
const sessionConfig = {
    store,
    name: 'session',
    secret: secret,
    resave: false,
    saveUninitialized: true,
    cookie: {
        httpOnly: true,
        expires: Date.now() + 1000 * 60 * 60 * 24 * 7,
        maxAge: 1000 * 60 * 60 * 24 * 7
    }
}

//session config
app.use(session(sessionConfig))

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

// passport config
app.use(passport.initialize());
app.use(passport.session());
passport.use(new LocalStrategy(User.authenticate()));
passport.serializeUser(User.serializeUser());
passport.deserializeUser(User.deserializeUser());

// setting local variables
app.use((req, res, next) => {
    res.locals.currentUser = req.user;
    res.locals.success = req.flash('success');
    res.locals.error = req.flash('error');
    next();
})

// setting prefix and using routes

app.use('/', userRoutes);
app.use('/landscapes', landscapeRoutes)
app.use('/landscapes/:id/reviews', reviewRoutes)

// routes

app.get('/', (req, res) => {
    res.render('home');
})

// wrong url
app.all('*', (req, res, next) => {
    next(new ExpressError('Page Not Found', 404))       // pass the error to the error handler
})

// error handler
app.use((err, req, res, next) => {
    const { statusCode = 500 } = err;
    if (!err.message) err.message = 'Oh No, Something Went Wrong!'
    res.status(statusCode).render('error', { err })
})

// listening

const port = process.env.PORT || 3000

app.listen(port, () => {
    console.log(`Listening on port: ${port}`);
})