https://github.com/akunna1/about-middlewares

Node-Express Middlewares in depth with explanations and examples
https://github.com/akunna1/about-middlewares

backend express-js middleware node-js

Last synced: 14 days ago
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Node-Express Middlewares in depth with explanations and examples

• Host: GitHub
• URL: https://github.com/akunna1/about-middlewares
• Owner: akunna1
• Created: 2024-08-14T19:26:43.000Z (3 months ago)
• Default Branch: main
• Last Pushed: 2024-08-14T19:55:24.000Z (3 months ago)
• Last Synced: 2024-11-02T22:04:14.139Z (14 days ago)
• Topics: backend, express-js, middleware, node-js
• Language: JavaScript
• Homepage:
• Size: 3.91 KB
• Stars: 0
• Watchers: 1
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

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README

        
#### About-Middlewares

- Express is the framework for node.js

- Middleware functions are crucial for handling HTTP requests and responses

-  Middlewares are used to modify requests, handle responses, and control the flow of the application

-  They can be built-in, third-party, or custom, and are essential for performing tasks such as parsing data, logging, handling CORS, and managing errors

- These functions have access to the request (req), response (res), and the next function in the application's request-response cycle

  

Function components:

function (req, res, next) {

  // Middleware logic here

  next();

}

- req: The request object, which contains data about the HTTP request

- res: The response object, which allows one to send a response to the client

- next: A function that passes control to the next middleware in the stack. If not called, the request will hang

Examples of node.js middleware that work with the express framework:

- app.use(express.json()); --> Parses incoming JSON request bodies

- app.use(express.urlencoded({ extended: true })); --> Parses incoming URL-encoded request bodies (form submissions)

- app.use(express.static('public')); --> Serves static files from a directory

- app.use(cors()); --> Enables Cross-Origin Resource Sharing

- app.use(morgan('tiny')); --> HTTP request logger middleware (records details about incoming HTTP requests and their responses)

- app.use(helmet()); --> Helps secure Express apps by setting various HTTP headers (to protect your application from common web vulnerabilities)

- app.use(compression()); --> Gzip compression middleware for responses (to reduce the size of the data being transmitted over the network)

Another example:

- error handling middleware

function errorHandler(err, req, res, next) {

  console.error(err.stack); // Logging error stack trace

  res.status(500).send('Something went wrong!');

}

app.use(errorHandler);