server.js

const express = require("express");
const app = express();
const cors = require("cors");
const dotenv = require("dotenv");
dotenv.config();
const userService = require("./user-service.js");

//this module is used primarily to "sign" our JSON payload with a 'secret' and generate the token 
const jwt = require('jsonwebtoken');
const passport = require("passport");
const passportJWT = require("passport-jwt");

const HTTP_PORT = process.env.PORT || 8080;

//JSON Web Token setup 
let ExtractJwt = passportJWT.ExtractJwt;
let JwtStrategy = passportJWT.Strategy;

//configure it's options 
let jwtOptions = {
    jwtFromRequest : ExtractJwt.fromAuthHeaderWithScheme('JWT'),
    secretOrKey : process.env.JWT_SECRET,
};

console.log('jwtOptions:', jwtOptions);
console.log('process.env.JWT_SECRET:', process.env.JWT_SECRET);

//jwt strategy middleware function checks if there is a valid jwt_payload and if so invoke the next() method
let strategy = new JwtStrategy(jwtOptions, function(jwt_payload, next){
    console.log('payload received', jwt_payload);

    if(jwt_payload){
        // The following will ensure that all routes using
        // passport.authenticate have a req.user._id, req.user.userName values
        // that matches the request payload data
        next(null, {
            _id : jwt_payload._id,
            userName : jwt_payload.userName,
        });
    } else { //f the jwt_payload is invalid, the next() method will be called without the payload data
        next(null, false); // which will cause our server to return a 401 (Unauthorized) error
    }
});

//tell passport to use our strategy
passport.use(strategy);

//add passport as application-level middleware
app.use(passport.initialize());

app.use(cors());
app.use(express.json());

app.post("/api/user/register", (req, res) => {
    userService.registerUser(req.body)
    .then((msg) => {
        res.json({ "message": msg });
    }).catch((msg) => {
        res.status(422).json({ "message": msg });
    });
});

app.post("/api/user/login", (req, res) => {
    userService.checkUser(req.body)
    .then((user) => {
        //use the returned user object to generate a payload object, this will be the content that JWT sends back to the client
        let payload = {
            _id : user._id,
            userName : user.userName
        };

        //Sign the payload with the secret from 
        let token = jwt.sign(payload, jwtOptions.secretOrKey);

        res.json({ "message": "login successful", token : token});
    }).catch(msg => {
        res.status(422).json({ "message": msg });
    });
});

app.get("/api/user/favourites", passport.authenticate('jwt', {session: false}), (req, res) => {
    userService.getFavourites(req.user._id)
    .then(data => {
        res.json(data);
    }).catch(msg => {
        res.status(422).json({ error: msg });
    })

});

app.put("/api/user/favourites/:id", passport.authenticate('jwt', {session: false}), (req, res) => {
    userService.addFavourite(req.user._id, req.params.id)
    .then(data => {
        res.json(data)
    }).catch(msg => {
        res.status(422).json({ error: msg });
    })
});

app.delete("/api/user/favourites/:id", passport.authenticate('jwt', {session: false}), (req, res) => {
    userService.removeFavourite(req.user._id, req.params.id)
    .then(data => {
        res.json(data)
    }).catch(msg => {
        res.status(422).json({ error: msg });
    })
});

app.get("/api/user/history", passport.authenticate('jwt', {session: false}), (req, res) => {
    userService.getHistory(req.user._id)
    .then(data => {
        res.json(data);
    }).catch(msg => {
        res.status(422).json({ error: msg });
    })

});

app.put("/api/user/history/:id", passport.authenticate('jwt', {session: false}), (req, res) => {
    userService.addHistory(req.user._id, req.params.id)
    .then(data => {
        res.json(data)
    }).catch(msg => {
        res.status(422).json({ error: msg });
    })
});

app.delete("/api/user/history/:id", passport.authenticate('jwt', {session: false}), (req, res) => {
    userService.removeHistory(req.user._id, req.params.id)
    .then(data => {
        res.json(data)
    }).catch(msg => {
        res.status(422).json({ error: msg });
    })
});

userService.connect()
.then(() => {
    app.listen(HTTP_PORT, () => { console.log("API listening on: " + HTTP_PORT) });
})
.catch((err) => {
    console.log("unable to start the server: " + err);
    process.exit();
});