req.cookies with cookie-parser in Express - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of the cookie-parser middleware in Express?

cookie-parser helps Express read cookies sent by the browser. It parses cookie headers and makes cookies available as req.cookies.

beginner

How do you access cookies in an Express route handler after using cookie-parser?

You access cookies using req.cookies. For example, req.cookies.username gives the value of the cookie named 'username'.

beginner

Show the code to set up cookie-parser in an Express app.

<pre>import express from 'express';
import cookieParser from 'cookie-parser';

const app = express();
app.use(cookieParser());</pre>

intermediate

What happens if you try to read req.cookies without using cookie-parser?

req.cookies will be undefined because Express does not parse cookies by default. You must use cookie-parser to populate it.

intermediate

Can cookie-parser parse signed cookies? How do you enable this?

Yes, cookie-parser can parse signed cookies if you provide a secret string when you initialize it, like app.use(cookieParser('secret')). Signed cookies appear in req.signedCookies.

What does req.cookies contain in an Express app using cookie-parser?

A The session data stored on the server

B The raw cookie header string

C An object with cookie names and values sent by the client

D The response cookies to be sent

req.cookies is an object mapping cookie names to their values sent by the client browser.

How do you add cookie-parser middleware to an Express app?

A app.use(cookieParser())

B app.cookieParser()

C app.set('cookie-parser')

D app.use(express.cookieParser())

You add it by calling app.use(cookieParser()) after importing it.

If you want to read signed cookies, where do you find them?

A req.cookies

B req.signed

C req.headers.cookie

D req.signedCookies

Signed cookies are available in req.signedCookies after using cookie-parser with a secret.

What will happen if you forget to use cookie-parser but try to access req.cookies?

A <code>req.cookies</code> will be undefined

B <code>req.cookies</code> will be an empty object

C Express will throw an error

D Cookies will be parsed automatically

Without cookie-parser, req.cookies is undefined because Express does not parse cookies by default.

Which of these is NOT a feature of cookie-parser?

A Parsing cookies from request headers

B Signing cookies automatically on response

C Providing <code>req.cookies</code> and <code>req.signedCookies</code>

D Supporting cookie signature verification

cookie-parser parses cookies but does not sign cookies on response. Signing cookies is done when setting cookies manually.

Explain how to use cookie-parser in an Express app to read cookies sent by the browser.

Think about middleware setup and how Express handles requests.

Describe the difference between req.cookies and req.signedCookies when using cookie-parser.

Consider how cookie security is handled.