How to Set, View and Manipulate Cookies using ‘Response.cookie()’ and Postman ?

Cookies enable websites to store small pieces of information on a user’s device. It helps enhance user experience and enable various functionalities. In this article, we’ll explore a simple way to manipulate cookies using the ‘Response.cookie()’ function

Prerequisite:

• Basics of Nodejs
• Basics of Expressjs
• One should be able to make a basic express server.
• How to use Postman.

The ‘Response.cookie()‘ function is like a tool for developers to handle cookies in what they send back to a user’s browser. With it, they can control stuff like the cookie’s name, the value when it expires, and how secure it is.

Syntax:

app.get('/set-cookie', (req, res) => {
    res.cookie('username', 'JohnDoe', { maxAge: 900000, httpOnly: true });
    res.send('Cookie has been set!');
});

In the above syntax, when a user accesses the ‘/set-cookie’ route, the server responds by setting a cookie named ‘username’ with the value ‘JohnDoe.’

Steps to set and view cookie:

Step 1: Initiallized an Express application and install the required dependencies.

npm init -y 
npm i express cookie-parser

Folder Structure:

The updated dependencies in package.json file will look like:

"dependencies": {
    "cookie-parser": "^1.4.6",
    "express": "^4.18.2"
}

Example: Create a server.js file and write the following code.

Javascript

//server.js

const express = require("express");
const cookieParser = require("cookie-parser");
const app = express();

// Use cookie-parser middleware to parse cookies
app.use(cookieParser());

// Set up a route to set a cookie
app.get("/set-cookie", (req, res) => {
    // Set a cookie named 'username' with the value 'JohnDoe'
    res.cookie("username", "JohnDoe", { maxAge: 900000, httpOnly: true });

    // Send a response
    res.send("Cookie has been set!");
});

// Set up a route to view cookies
app.get("/view-cookies", (req, res) => {
    // Send a response with the cookies received from the client
    res.send(`Cookies: ${JSON.stringify(req.cookies)}`);
});

// Start the server on port 3000
app.listen(3000, () => {
    console.log("Server is running on port 3000");
});

Use below command to run “server.js”.

node server.js 

Testing Route using Postman:

Step 1: Enter the url in the postman ,”http://localhost:3000/set-cookie”. This will set the cookie username and value as “JhonDoe”.

Step 2: Hit the url “http://localhost:3000/view-cookies“. You will get the cookie value which was set in above step.

Response Process:

All steps to set cookie

Conclusion:

By following above article, you can set cookie data that can be sent to browser. The cookies data cannot be accessed by client side browser script. In this article,you learned how to set or manuplate cookie and view the cookie in response.