Tutorial Playlist

Cyber Security Tutorial: A Step-by-Step Guide

Overview

What is Cybersecurity?

Lesson - 1

Cyber Security for Beginners

Lesson - 2

How to Become a Cybersecurity Engineer?

Lesson - 3

What is Ethical Hacking?

Lesson - 4

What is Penetration Testing?: A Step-by-Step Guide

Lesson - 5

What Is SQL Injection: How to Prevent SQL Injection

Lesson - 6

How to Become an Ethical Hacker?

Lesson - 7

What Is a Firewall and Why Is It Vital?

Lesson - 8

The Complete Know-How on the

Lesson - 9

A Definitive Guide to Learn the SHA 256 Algorithm

Lesson - 10

What Is a Ransomware Attack and How Can You Prevent It?

Lesson - 11

A Look at the Top 5 Programming Languages for Hacking

Lesson - 12

The Most Informative Guide on What Is an IP Address?

Lesson - 13

The Best Ethical Hacking + Cybersecurity Books

Lesson - 14

10 Types of Cyber Attacks You Should Be Aware in 2022

Lesson - 15

The Top Computer Hacks of All Time

Lesson - 16

Top 6 Cyber Security Jobs in 2022

Lesson - 17

The Best Guide to The Top Cybersecurity Interview Questions

Lesson - 18

What Is a Brute Force Attack and How to Protect Our Data Against It?

Lesson - 19

The Top 8 Cybersecurity Skills You Must Have

Lesson - 20

Your Guide to Choose the Best Operating System Between Parrot OS vs. Kali Linux

Lesson - 21

All You Need to Know About Parrot Security OS

Lesson - 22

The Best and Easiest Way to Understand What Is a VPN

Lesson - 23

What Is NMap? A Comprehensive Tutorial for Network Mapping

Lesson - 24

What Is Google Dorking? Your Way to Becoming the Best Google Hacker

Lesson - 25

Your Best Guide to a Successful Cyber Security Career Path

Lesson - 26

The Value of Python in Ethical Hacking and a Password Cracking Tutorial

Lesson - 27

The Best Guide to Understand What Is TCP/IP Model?

Lesson - 28

What Are Keyloggers and Its Effect on Our Devices?

Lesson - 29

Best Guide to Understand the Importance of What Is Subnetting

Lesson - 30

Your Guide to What Is 5G and How It Works

Lesson - 31

How to Crack Passwords and Strengthen Your Credentials Against Brute-Force

Lesson - 32

A Look at ‘What Is Metasploitable’, a Hacker’s Playground Based on Ubuntu Virtual Machines

Lesson - 33

One-Stop Guide to Understanding What Is Distance Vector Routing?

Lesson - 34

Best Walkthrough for Understanding the Networking Commands

Lesson - 35

Best Guide to Understanding the Operation of Stop-and-Wait Protocol

Lesson - 36

The Best Guide to Understanding the Working and Importance of Go-Back-N ARQ Protocol

Lesson - 37

What Are Digital Signatures: A Thorough Guide Into Cryptographic Authentication

Lesson - 38

The Best Spotify Data Analysis Project You Need to Know

Lesson - 39

A One-Stop Solution Guide to Understand Data Structure and Algorithm Complexity

Lesson - 40

Your One-Stop Guide ‘On How Does the Internet Work?’

Lesson - 41

An Introduction to Circuit Switching and Packet Switching

Lesson - 42

One-Stop Guide to Understanding What Is Network Topology?

Lesson - 43

A Deep Dive Into Cross-Site Scripting and Its Significance

Lesson - 44

The Best Walkthrough on What Is DHCP and Its Working

Lesson - 45

A Complete Look at What a Proxy Is, Along With the Working of the Proxy Server

Lesson - 46

A Detailed Guide to Understanding What Identity and Access Management Is

Lesson - 47

The Best Guide to Understanding the Working and Effects of Sliding Window Protocol

Lesson - 48

The Best Guide That You’ll Ever Need to Understand Typescript and Express

Lesson - 49

Express REST API

Lesson - 50

All You Need to Know About Express JS Middleware

Lesson - 51

An Absolute Guide to Know Everything on Expressions in C

Lesson - 52

A Definitive Guide on How to Create a Strong Password

Lesson - 53

Ubuntu vs. Debian: A Look at Beginner Friendly Linux Distribution

Lesson - 54

Your One-Stop Guide to Learn Command Prompt Hacks

Lesson - 55

Best Walkthrough to Understand the Difference Between IPv4 and IPv6

Lesson - 56

What Is Kali NetHunter? A Deep Dive Into the Hackbox for Android

Lesson - 57

A Perfect Guide That Explains the Differences Between a Hub and a Switch

Lesson - 58

The Best Guide to Help You Understand What Is Network Security

Lesson - 59

What Is CIDR? And Its Importance in the Networking Domain

Lesson - 60
All You Need to Know About Express JS Middleware

Express is a node js web application framework that provides broad features for building web and mobile applications. It is used to build a single page, multipage, and hybrid web application.

This tutorial on Express Middleware will walk you through all the topics on Express js Middleware.

What Is Middleware?

  • A request handler with access to the application's request-response cycle is known as middleware. 
  • It's a function that holds the request object, the response object, and the middleware function.
  • Middleware can also send the response to the server before the request. 
  • The next middleware function is commonly represented as a variable named next.
  • Simply middleware is a function that can only be applied using routes. 
  • We can access and modify request and response data using middleware.

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/ExpressJS_Middleware_1

Functions of Middleware

  • Executes any code 
  • We can make changes to the request-response objects
  • Middleware can also End the request-response cycle
  • Middleware can call the next middleware function in a stack 

We use these functions to modify our middleware to perform many tasks. If we want to block our site for some country or if we're going to check the authentication of a user etc., we use middleware for that.

Creating Middleware 

Now we will create an Express middleware for that we will create a simple Express API. We can create middleware in a router file, but the easiest method is to create a separate middleware file and then execute it; creating and using middleware is very simple.

So to create middleware, we need to install all the packages to run express middleware.

ExpressJS_Middleware_2

Fig - app.js

  • Now open your terminal and run this file we will see our server is running.
  • After this, go to the local server and type localhost:4000
  • Now we will call our next parameter, 
  • In express framework, next is a function

ExpressJS_Middleware_3

Fig - middleware

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ExpressJS_Middleware_4

Fig - output 

  • Now we will go to the home page that we have created.

ExpressJS_Middleware_5

Fig - output home page

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Conclusion 

This article has touched on what is middleware, the functions of middleware, and we have created a simple middleware using Express js. You can enroll in Simplilearn’s Node JS certification training to learn more about Express. This certification training course will upskill you on how to use Express.js, NPM, NPM Vet, REST, shrink-wrap, Express.js with MongoDB, and SQLite CRUD operations. This Express JS training focuses on the fundamental ideas of Node JS and Express Js and gives you hands-on experience developing an HTTP server.

If you have any questions or feedback, do let us know in the comments section of the “Express js Middleware” tutorial, and our experts will get back to you at the earliest.

About the Author

Anubhav SharmaAnubhav Sharma

Anubhav is a Research Analyst. He enjoys working on dynamic projects where he can learn new things. He is responsible and diligent. Being a resident of Jammu, he loves nature and exploring new places.

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