app.js

// NPM modules
require("dotenv").config();
const express = require("express");
const bodyParser = require("body-parser");
const ejs = require("ejs");
const mongoose = require("mongoose");
const session = require("express-session");
const passport = require("passport");
const passportLocalMongoose = require("passport-local-mongoose");
const GoogleStrategy = require("passport-google-oauth20").Strategy;
const findOrCreate = require("mongoose-findorcreate");
const atlasPass = process.env.ATLAS_PASS;
const app = express();

// initialize ejs, body-parser and express.static
app.use(express.static("public"));
app.set("view engine", "ejs");
app.use(bodyParser.urlencoded({
  extended: true
}));

// initialize session + inital configuration
app.use(session({
  secret: "Our little secret.",
  resave: false,
  saveUninitialized: false
}));

// initialize passport
app.use(passport.initialize());
// use passport to set-up the session
app.use(passport.session());

// connect to MongoDB Atlas
mongoose.connect("mongodb+srv://admin-jan:" + atlasPass + "@cluster0.njvgj.mongodb.net/userDB", {
  useNewUrlParser: true,
  useUnifiedTopology: true
});
// fix deprecation warning
mongoose.set("useCreateIndex", true);

// create DB schema (userSchema)
const userSchema = new mongoose.Schema({
  email: String,
  password: String,
  googleId: String,
  secret: String
});

// add passportLocalMongoose to the userSchema - hash/salt/save password to Mongo DB
userSchema.plugin(passportLocalMongoose);
userSchema.plugin(findOrCreate);

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

// setup Passport - ceate local login strategy
passport.use(User.createStrategy());
// passport - serialize/deserialize
passport.serializeUser(function(user, done) {
  done(null, user.id);
});
passport.deserializeUser(function(id, done) {
  User.findById(id, function(err, user) {
    done(err, user);
  });
});

passport.use(new GoogleStrategy({
    clientID: process.env.CLIENT_ID,
    clientSecret: process.env.CLIENT_SECRET,
    callbackURL: "https://obscure-sierra-42963.herokuapp.com/auth/google/secrets",
    userProfileURL: "https://www.googleapis.com/oauth2/v3/userinfo"
  },
  function(accessToken, refreshToken, profile, cb) {
    User.findOrCreate({
      googleId: profile.id
    }, function(err, user) {
      return cb(err, user);
    });
  }
));


app.get("/", function(req, res) {
  res.render("home");
});

app.get("/auth/google",
  passport.authenticate("google", {
    scope: ["profile"]
  })
);

app.get("/auth/google/secrets",
  passport.authenticate("google", {
    failureRedirect: "/login"
  }),
  function(req, res) {
    res.redirect("/secrets");
  });

app.get("/login", function(req, res) {
  res.render("login");
});

app.get("/register", function(req, res) {
  res.render("register");
});

app.get("/secrets", function(req, res) {
  User.find({
    "secret": {
      $ne: null
    }
  }, function(err, foundUsers) {
    if (err) {
      console.log(err);
    } else {
      res.render("secrets", {
        users: foundUsers
      });
    }
  });
});

app.get("/submit", function(req, res) {
  if (req.isAuthenticated()) {
    res.render("submit");
  } else {
    res.redirect("/login");
  }
});

app.post("/submit", function(req, res) {
  const submittedSecret = req.body.secret;
  User.findById(req.user.id, function(err, foundUser) {
    if (err) {
      console.log(err);
    } else {
      if (foundUser) {
        foundUser.secret = submittedSecret;
        foundUser.save(function() {
          res.redirect("/secrets");
        });
      }
    }
  })
});

app.get("/logout", function(req, res) {
  // passport logout
  req.logout();
  res.redirect("/");
});

// new user registration (passport-local-mongoose)
app.post("/register", function(req, res) {
  User.register({
    username: req.body.username
  }, req.body.password, function(err, user) {
    if (err) {
      console.log(err);
      res.redirect("register");
    } else {
      passport.authenticate("local")(req, res, function() {
        res.redirect("/secrets");
      });
    }
  });
});

app.post("/login", function(req, res) {
  const user = new User({
    username: req.body.username,
    password: req.body.password
  });
  // passport login
  req.login(user, function(err) {
    if (err) {
      console.log(err);
    } else {
      passport.authenticate("local")(req, res, function() {
        res.redirect("/secrets");
      });
    }
  })
});

let port = process.env.PORT;
if (port == null || port == "") {
  port = 3000;
}

app.listen(port, function() {
  console.log("Server started successfully!");
});