ozenero | Mobile & Web Programming Tutorials

The tutorial is Part 1 of the series: Angular & Nodejs JWT Authentication fullstack | Nodejs/Express RestAPIs + JWT + BCryptjs + Sequelize + MySQL. In this part, we show you Overview and Architecture of the System (from Angular frontend to Nodejs/Express backend). You will see the combination of big components and what you need to do for the security part (authentication & authorization) of full-stack web development.

– Part 2: Build Backend
– Part 3: Build Frontend

JSON Web Token

JSON Web Token (JWT) defines a compact and self-contained way for securely transmitting information between parties as a JSON object.

-> Scenarios where JSON Web Tokens are useful:

Authorization: the most common scenario for using JWT. Single Sign On is a feature that widely uses JWT
Information Exchange: Because JWTs can be signed, JSON Web Tokens are a good way of securely transmitting information between parties.

JSON Web Tokens consist of 3 parts:

Header
Payload
Signature

-> JWT looks like Header-Base64-String.Payload-Base64-String.Signature-Base64-String

Header consists of two parts:

token type.
hashing algorithm.

-> Example:

{
  "alg": "HS256",
  "typ": "JWT"
}

Payload contains the claims. Claims are statements about an entity and additional information.
There are 3 types of claims ->

Registered claims -> These are a set of predefined claims: iss (issuer), exp (expiration time), sub (subject)
Public claims
Private claims

Example ->

{
  "id": 3,
  "iat": 1538339534,
  "exp": 1538425934
}

Signature -> To create the signature part you have to take the encoded header, the encoded payload, a secret, the algorithm specified in the header, and sign that.

Example ->

HMACSHA512(
  base64UrlEncode(header) + "." +
  base64UrlEncode(payload),
  your-256-bit-secret
)

Combine all together, we get 3 Base64-URL strings separated by dots,

Example:

– Encoded ->

eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpZCI6MywiaWF0IjoxNTM4MzM5NTM0LCJleHAiOjE1Mzg0MjU5MzR9.wKse6-ERNP4g_sPBdM72GZgpNpHH87UGbzYH3_0mdpo

– Decoded ->

Angular Nodejs/Express JWT Authentication example

Goal

We will build an application, from frontend (Angular) to backend (Nodejs/Express), which allows users to register, login account. This application is secured with JWT (JSON Web Token) authentication and Nodejs middleware security. Then, depending on the role of current User (user, pm or admin), this system accepts what he can access:

The diagram below show how our system handles User Registration and User Login processes:

Video

Full Stack Architecture

Nodejs/Express back-end with Middleware Security

HTTP request that matches route will be accepted by CORS Middleware before coming to Security layer.

Security layer includes:
– JWT Authentication Middleware: verify SignUp, verify token
– Authorization Middleware: check User’s roles

Main Business Logic Processing interacts with database via Sequelize and send HTTP response (token, user information, data based on roles…) to client.

Angular front-end with Interceptor

– app.component is the parent component that contains routerLink and router-outlet for routing. It also has an authority variable as the condition for displaying items on navigation bar.
– user.component, pm.component, admin.component correspond to Angular Components for User Board, PM Board, Admin Board. Each Board uses user.service to access authority data.
– register.component contains User Registration form, submission of the form will call auth.service.
– login.component contains User Login form, submission of the form will call auth.service and token-storage.service.

– user.service gets access to authority data from Server using Angular HttpClient ($http service).
– auth.service handles authentication and signup actions with Server using Angular HttpClient ($http service).
– every HTTP request by $http service will be inspected and transformed before being sent to the Server by auth-interceptor (implements HttpInterceptor).
– auth-interceptor check and get Token from token-storage.service to add the Token to HTTP Request Header.

– token-storage.service manages Token inside Browser’s sessionStorage.

For more details about: