express | Chinese Rule of Eight

ref – https://scotch.io/tutorials/authenticate-a-node-js-api-with-json-web-tokens

In part 1, we set up a simple project where we let a client create a user through a public URL /setup, then display all the users via /api/users.

Next, let’s make sure that we can authenticate a user and then protect those routes using Express route middleware and requiring a token.

Authenticating and Creating a Token

// route to authenticate a user (POST http://localhost:8080/api/authenticate)

apiRoutes.post('/authenticate', function(req, res) {

console.log('(POST http://localhost:8080/api/authenticate)');

//User is model object made by mongoose

// mongoose's findOne function to find the user

User.findOne({

}, function(err, user) {

if (err) throw err;

if (!user) {

res.json({ success: false, message: 'Authentication failed. User not found.' });

} else if (user) {

//user with that name is returned...we just have to check if the pwds match

// check if password matches

if (user.password != req.body.password) {

res.json({ success: false, message: 'Authentication failed. Wrong password.' });

} else {

console.log('user found, and password is correct');

// if user is found and password is right

// create a token, jsonwebtoken to create the token.

var token = jwt.sign(user, app.get('superSecret'), {

expiresInMinutes: 1440 // expires in 24 hours

});

// return the information including token as JSON

res.json({

success: true,

message: 'Enjoy your token!',

token: token

});

}

});

We then use Postman to query it like so

why – form-urlencoded vs form-data

To summarize, form-urlencoded has a low fixed cost, but high variable for special characters, so application/x-www-form-urlencoded is good for short messages like those found in most basic web forms. On the other hand, form-data has a high fixed costs due to the additional MIME headers prepended to each message chunk, but low variable cost for special characters, so multipart/form-data is good for long messages such images or large files.

Now, copy that whole token string somewhere to be used later.

Protecting URLS

Now let’s protect /api and /api/users by forcing clients to provide the token whenever they need to access these urls.

So for our var apiRoutes that we get from express.Routes(), we have that routing variable use a function to process requests.

We make it run a middleware function by using .use on it. We basically check the requests’ headers to see if the key x-access-token has a valid value. That value should be the token value we received earlier. If the token is valid, everything checks through via the next(), and we run to the apiRoutes.get(‘/users’, function(req, res) {}); function definitions which gets the user from the database and gives it back as a json response.

// route middleware to verify a token

apiRoutes.use(function(req, res, next) {

console.log('apiRoutes.use function');

//X-ACCESS-TOKEN is the key, we need to give it value of token

//so it can authenticate us

console.log("req.body.token: " + req.body.token);

console.log("req.query.token: " + req.query.token);

console.log("req.headers[x-access-token]: " + req.headers['x-access-token']);

// check header or url parameters or post parameters for token

var token = req.body.token || req.query.token || req.headers['x-access-token'];

// decode token

if (token) {

// verifies secret and checks exp

jwt.verify(token, app.get('superSecret'), function(err, decoded) {

if (err)

{

return res.json({ success: false, message: 'Failed to authenticate token.' });

}

else

{

// if everything is good, save to request for use in other routes

req.decoded = decoded;

next();

}

});

} else {

// if there is no token

// return an error

return res.status(403).send({

success: false,

message: 'No token provided.'

});

}

});

For example, if you were to hit http://localhost:8080/api/ or http://localhost:8080/api/ it will run this function definition first….see that x-access-token has not been defined in the headers and return you an error json message.

When the tokens are valid, you’ll see the valid json data returned. If you are to use POSTman, here’s what it should look like:

ref – https://scotch.io/tutorials/authenticate-a-node-js-api-with-json-web-tokens

We’ll build a quick API using Node and Express and we’ll be using POSTman to test it.

Create an application directory, then in your mac terminal:

$ npm install express body-parser morgan mongoose jsonwebtoken –save

express is the popular Node framework
mongoose is how we interact with our MongoDB database
morgan will log requests to the console so we can see what is happening
body-parser will let us get parameters from our POST requests
jsonwebtoken is how we create and verify our JSON Web Tokens

The –save modifier will also save these packages to our package.json file.

After all the packages have been downloaded, you will see a node_modules folder. The packages are installed inside there.

User Model (/models/user.js)

In your project directory, create models folder. Then inside that models folder, you create user.js file.

The user model that we define will be used when creating and getting users. To create a Mongoose model, let’s create the file app/models/user.js

var mongoose = require('mongoose');

var Schema = mongoose.Schema;

// set up a mongoose model and pass it using module.exports

module.exports = mongoose.model('User', new Schema({

password: String,

admin: Boolean

}, { collection: 'user' })

);

Now let’s create a configuration file to store configuration settings for our application.

config.js (/config.js)

Basically, the database is hosted on our local machine.

module.exports = {

//secret: used when we create and verify JSON Web Tokens

'secret': 'ilovescotchyscotch',

'database': 'mongodb://localhost/PersonDatabase'

};

secret: used when we create and verify JSON Web Tokens
database: the URI with username and password to your MongoDB installation

Note: You should be running GULP for your working environment so that when you make changes, it will automatically help you save. In your gulpfile.js, make sure that gulp.task, script has the string “server.js”.

server.js

Set up all the package variables and db connections

// =======================

// get the packages we need ============

// =======================

var express = require('express');

var app = express();

var bodyParser = require('body-parser');

var morgan = require('morgan');

var mongoose = require('mongoose');

var jwt = require('jsonwebtoken'); // used to create, sign, and verify tokens

var config = require('./config'); // get our config file

var User = require('./models/user'); // get our mongoose model

// =======================

// configuration =========

// =======================

var port = 8080; // used to create, sign, and verify tokens

mongoose.connect(config.database); // connect to database

var db = mongoose.connection;

db.on('error', console.error.bind(console, 'connection error:'));

db.once('open', function (callback) {

// yay!

console.log('mongoose db connected');

});

Then we have our app use body parser for POST, morgan for throwing logs to console outputs, and set our config file’s object secret to web token’s super secret key.

app.set('superSecret', config.secret); // secret variable

// use body parser so we can get info from POST and/or URL parameters

app.use(bodyParser.urlencoded({ extended: false }));

app.use(bodyParser.json());

// use morgan to log requests to the console

app.use(morgan('dev'));

public URL for home

Let’s create public URL for the home page and then start the server

// route to show a random message (GET http://localhost:8080/)

app.get('/', function(req, res) {

res.json({ message: '(GET http://localhost:8080/)' });

});

// =======================

// start the server ======

// =======================

app.listen(port);

console.log('Magic happens at http://localhost:' + port);

Open up a browser and go to

http://localhost:8080/

You’d get the json response:

{“message”:”(GET http://localhost:8080/)”}

If you look at your mac terminal, you’ll also see morgan’s log outputs.

Finally, we put a url where the server creates and inserts a new user along with a password into the database.

Public URL to create a user

app.get('/setup', function(req, res) {

// create a sample user

var nick = new User({

password: 'compaq', //You would protect your passwords by hashing it.

admin: true

});

// save the sample user

nick.save(function(err) {

if (err) throw err;

console.log('User saved successfully');

res.json({ success: true });

});

Open up a browser and put in

http://localhost:8080/setup

You will get the json data back:

{“success”:true}

This means that you have successfully inserted the user rtsao with pw compaq.

Showing Users through public URL

Put the following code above our routes:

// API ROUTES -------------------

// get an instance of the router for api routes

var apiRoutes = express.Router();

// route to return all users (GET http://localhost:8080/api/users)

apiRoutes.get('/users', function(req, res) {

console.log('(GET http://localhost:8080/api/users)');

User.find({}, function(err, users) {

res.json(users);

});

// apply the routes to our application with the prefix /api

app.use('/api', apiRoutes);

What this means is that the variable apiRoutes always has url start with /api.

Whatever url we specify for a certain request, its always /api/url paired with GET or POST..etc.

Hence in apiRoutes.get(‘/users’…) function definition, it just means for (GET http://localhost:8080/api/users) we will return all the users from the database.

So now when we hit:

http://localhost:8080/api/users

we get:

[{“_id”:”55973f3702e8b0094967b544″,”name”:”rtsao”,”password”:”compaq”,”admin”:true,”__v”:0},{“_id”:”55977f4b06112d75860f9af6″,”name”:”rtsao6680″,”password”:”abcde12345″,”admin”:true,”__v”:0}]

Full Code

/config.js

module.exports = {

//secret: used when we create and verify JSON Web Tokens

'secret': 'ilovescotchyscotch',

'database': 'mongodb://localhost/PersonDatabase'

};

/server.js

// =======================

// get the packages we need ============

// =======================

var express = require('express');

var app = express();

var bodyParser = require('body-parser');

var morgan = require('morgan');

var mongoose = require('mongoose');

var jwt = require('jsonwebtoken'); // used to create, sign, and verify tokens

var config = require('./config'); // get our config file

var User = require('./models/user'); // get our mongoose model

// =======================

// configuration =========

// =======================

var port = 8080; // used to create, sign, and verify tokens

mongoose.connect(config.database); // connect to database

var db = mongoose.connection;

db.on('error', console.error.bind(console, 'connection error:'));

db.once('open', function (callback) {

// yay!

console.log('mongoose db connected');

});

app.set('superSecret', config.secret); // secret variable

// use body parser so we can get info from POST and/or URL parameters

app.use(bodyParser.urlencoded({ extended: false }));

app.use(bodyParser.json());

// use morgan to log requests to the console

app.use(morgan('dev'));

// API ROUTES -------------------

// get an instance of the router for api routes

var apiRoutes = express.Router();

// route to return all users (GET http://localhost:8080/api/users)

apiRoutes.get('/users', function(req, res) {

console.log('(GET http://localhost:8080/api/users)');

User.find({}, function(err, users) {

res.json(users);

});

// apply the routes to our application with the prefix /api

app.use('/api', apiRoutes);

// http://localhost:8080/setup

app.get('/setup', function(req, res) {

// create a sample user

var nick = new User({

password: 'abcde12345', //You would protect your passwords by hashing it.

admin: true

});

// save the sample user

nick.save(function(err) {

if (err) throw err;

console.log('User saved successfully');

res.json({ success: true });

});

// route to show a random message (GET http://localhost:8080/)

app.get('/', function(req, res) {

res.json({ message: '(GET http://localhost:8080/)' });

});

// =======================

// start the server ======

// =======================

app.listen(port);

console.log('Magic happens at http://localhost:' + port);

/models/user.js

var mongoose = require('mongoose');

var Schema = mongoose.Schema;

// set up a mongoose model and pass it using module.exports

module.exports = mongoose.model('User', new Schema({

password: String,

admin: Boolean

}, { collection: 'user' })

);

Chinese Rule of Eight

Tag Archives: express

Authenticate web service urls part 2

Authenticating and Creating a Token

why – form-urlencoded vs form-data

Protecting URLS

Authenticate web service urls part 1

User Model (/models/user.js)

config.js (/config.js)

server.js

public URL for home

Public URL to create a user

Showing Users through public URL

Full Code

/config.js

/server.js

/models/user.js