server.js

// with mongoose-encryption

const express = require("express");
const bodyParser = require("body-parser");
const mongoose = require("mongoose");
const encrypt = require('mongoose-encryption');

const app = express();

mongoose.connect("mongodb://localhost:27017/userDB", {
    useNewUrlParser: true,
    useUnifiedTopology: true
});

const UserSchema = new mongoose.Schema({
    email: {
        type: String,
        required: true,
        unique: true
    },
    password: {
        type: String,
        required: true
    }
});

const secret = "This is a secret key, it should be unguessable";
UserSchema.plugin(encrypt, { secret: secret, encryptedFields: ['password'] });

const User = mongoose.model("User", UserSchema);

// urlencoded parser is used since the html form send data
// as urlencoded format with POST reqiest
app.use(bodyParser.urlencoded({ extended: true }));

// define the register GET route
app.get("/register", function(req, res) {
    res.sendFile(__dirname + "/register.html");
});

// define the login GET route
app.get("/login", function(req, res) {
    res.sendFile(__dirname + "/signin.html");
});

// define the register POST route
app.post("/register", function(req, res) {
    const email = req.body.email;
    const password = req.body.password;
    const newUser = User({ email: email, password: password });
    newUser.save(function(err) {
        if (!err) {
            res.redirect("/login");
        } else {
            res.send(err);
        }
    })
});

// define the login POST route
app.post("/login", function(req, res) {
    const email = req.body.email;
    const password = req.body.password;
    User.findOne({ email: email }, function(err, user) {
        if (err) {
            res.send(err);
        } else if (user) {
            if (password === user.password) {
                res.sendFile(__dirname + "/secret.html");
            } else {
                res.redirect("/login")
            }
        } else {
            res.redirect("/login");
        }
    });
});

///////////////////This is out secret page/////////////////////

// define the secret route
app.get("/secret", function(req, res) {
    res.sendFile(__dirname + "/secret.html");
});


app.listen(3000, function() {
    console.log(`Server started at port ${3000}`);
});