Class PPT

Agenda

• Middleware
• Crypto-Js
• JWT

Middleware

• Middleware is a function that runs between the request and the response in a web application.
• It is commonly used in backend frameworks like Express.js to modify, process, or control HTTP requests before sending a response.
• It Access Request (req) and Response (res) Objects
• It Modify Requests/Responses → Example: Adding headers, parsing JSON
• Run Code Before Sending a Response → Example: Authentication, Logging
• Call next() to Continue Execution → Passes control to the next middleware
• It is commonly used in express for
  1. Handling CORS (cors package)
  2. Parsing JSON data (express.json())
  3. Authentication & authorization

crypto-js

1. add/install the mysql module

   npm install crypto-js
   #OR
   yarn add crypto-js
   

2. Usage

   // import the module crypto-Js
   const cryptoJs = require("crypto-js")
   // use the encryption method to encrypt the password
   const encrypted = cryptoJs.SHA256(password)
   

JWT

• JSON Web Token (JWT) is an open standard (RFC 7519) that defines a compact and self-contained way for securely transmitting information between parties as a JSON object.
• This information can be verified and trusted because it is digitally signed. JWTs can be signed using a secret
• These are useful in
  1. Authorization
     • This is the most common scenario for using JWT.
     • Once the user is logged in, each subsequent request will include the JWT, allowing the user to access routes, services, and resources that are permitted with that token.
  2. Information Exchange
     • JSON Web Tokens are a good way of securely transmitting information between parties.
     • Because JWTs can be signed—for example, using public/private key pairs—you can be sure the senders are who they say they are.
     • Additionally, as the signature is calculated using the header and the payload, you can also verify that the content hasn't been tampered with.