1 $What is the primary communication protocol used by WebSockets?$

A.

UDP

B.

FTP

C.

HTTP

D.

TCP

2 $Which URL scheme is used for an unencrypted WebSocket connection?$

A.

ftp://

B.

wss://

C.

http://

D.

ws://

3 $Unlike HTTP, a WebSocket connection is:$

A.

One-way only

B.

Full-duplex and persistent

C.

Unreliable

D.

Stateless

4 $Which HTTP header is essential for the WebSocket handshake process?$

A.

Upgrade

B.

Authorization

C.

Accept

D.

Content-Type

5 $In a basic Node.js 'ws' server, which event is triggered when a client connects?$

A.

connection

B.

connect

C.

init

D.

open

6 $Which method is used to send a message from the server to a specific client instance in the 'ws' library?$

A.

client.write()

B.

client.emit()

C.

client.push()

D.

client.send()

7 $What does Socket.IO provide that native WebSockets do not handle automatically?$

A.

HTTP requests

B.

JSON parsing

C.

TCP connections

D.

Automatic reconnection and fallback support

8 $In Socket.IO, how do you send a message to all connected clients?$

A.

socket.emit('msg', data)

B.

io.sendToAll(data)

C.

io.emit('msg', data)

D.

socket.broadcast.emit('msg', data)

9 $Which Socket.IO method is used to send a message to everyone except the sender?$

A.

socket.broadcast.emit()

B.

socket.send()

C.

socket.toAll()

D.

io.emit()

10 $In Express.js, what is 'middleware'?$

A.

A CSS preprocessor

B.

A database driver

C.

Functions that have access to the request and response objects

D.

A front-end framework

11 $What is the purpose of the 'next' function in Express middleware?$

A.

To redirect the user

B.

To restart the server

C.

To send the response immediately

D.

To pass control to the next middleware function

12 $Which Express method is used to mount middleware functions at a specific path?$

A.

app.mount()

B.

app.bind()

C.

app.middleware()

D.

app.use()

13 $What does app.all('/api/*', ...) do?$

A.

Handles only POST requests for /api/

B.

Handles only GET requests for /api/

C.

Handles requests from all IP addresses

D.

Handles all HTTP methods (GET, POST, etc.) for routes starting with /api/

14 $What is the primary purpose of the cookie-parser middleware?$

A.

To populate req.cookies with an object keyed by the cookie names

B.

To eat cookies

C.

To delete all cookies on the client

D.

To encrypt cookies automatically

15 $Where does cookie-session store the session data?$

A.

On the server's database

B.

In the server's memory

C.

In a Redis cache

D.

On the client-side within the cookie itself

16 $Where does express-session store the session data by default?$

A.

In server-side memory (MemoryStore)

B.

In a text file

C.

In the URL

D.

On the client browser

17 $Which option allows Socket.IO clients to join a specific channel or 'room'?$

A.

socket.join('room1')

B.

socket.room('room1')

C.

io.join('room1')

D.

socket.enter('room1')

18 $In Socket.IO, how do you send a message only to clients in a specific room?$

A.

io.in('roomName').broadcast(data)

B.

io.emit('roomName', data)

C.

io.to('roomName').emit('event', data)

D.

socket.send('roomName', data)

19 $What argument is required to initialize cookie-parser if you want to use signed cookies?$

A.

A file path

B.

A database connection

C.

A secret string

D.

The session ID

20 $When using express-session, which property is added to the request object?$

A.

req.storage

B.

req.cookies

C.

req.session

D.

req.cache

21 $Which express-session option forces the session to be saved back to the store, even if it wasn't modified?$

A.

saveUninitialized

B.

cookie

C.

resave

D.

secret

22 $In middleware, what happens if you call next() with an error argument, like next(new Error('Fail')) ?$

A.

It skips to the next non-error middleware

B.

It skips to the next error-handling middleware

C.

The server crashes

D.

It reloads the page

23 $What is the signature of a standard Express error-handling middleware function?$

A.

(req, res, next)

B.

(err, req, res)

C.

(req, res)

D.

(err, req, res, next)

24 $To serve static files such as images or CSS files in Express, which built-in middleware is used?$

A.

express.assets()

B.

express.static()

C.

express.files()

D.

express.public()

25 $Which library is the client-side counterpart to the Node.js 'socket.io' package?$

A.

websocket.js

B.

ws-client

C.

socket-client.js

D.

socket.io-client

26 $In a WebSocket 'message' event, the data received is typically:$

A.

Always an Array

B.

Always a String or Buffer

C.

Always an Integer

D.

Always a JSON object

27 $Which cookie-session option helps prevent Cross-Site Scripting (XSS) attacks by preventing client-side scripts from accessing the cookie?$

A.

secure: true

B.

signed: true

C.

maxAge: 1000

D.

httpOnly: true

28 $If you want middleware to run for every request to the application, how should you mount it?$

A.

app.post(middleware)

B.

app.get(middleware)

C.

app.use(middleware)

D.

app.use('/home', middleware)

29 $What is the default name of the cookie used by express-session to store the session ID?$

A.

session_id

B.

jsessionid

C.

connect.sid

D.

express.sid

30 $In Socket.IO, what is a 'Namespace'?$

A.

A type of error

B.

A separate communication channel allowing multiplexing over a single connection

C.

A database table

D.

A variable name

31 $How do you access signed cookies in Express if cookie-parser is set up with a secret?$

A.

req.secretCookies

B.

req.signedCookies

C.

req.cookies

D.

req.secureCookies

32 $Which method removes a specific session in express-session ?$

A.

req.session.clear()

B.

req.session.delete()

C.

req.session.destroy()

D.

req.session.remove()

33 $When using app.use(bodyParser.json()), what does this middleware do?$

A.

Parses incoming requests with JSON payloads

B.

Sends JSON responses

C.

Encrypts JSON data

D.

Validates JSON syntax only

34 $In Socket.IO, what does the volatile flag do? e.g., socket.volatile.emit(...)$

A.

Sends the message but allows it to be lost if the client is not ready

B.

Ensures the message is encrypted

C.

Sends the message repeatedly until acknowledged

D.

Deletes the message immediately after sending

35 $What is the main disadvantage of cookie-session compared to express-session ?$

A.

It only works with HTTPS

B.

It cannot store large amounts of data (limited by cookie size)

C.

It requires a database

D.

It is slower

36 $Which event is fired in Socket.IO when a client disconnects?$

A.

end

B.

disconnect

C.

halt

D.

stop

37 $How can you limit middleware to a specific HTTP verb (e.g., POST) for a specific path?$

A.

app.post('/path', middleware)

B.

app.use()

C.

app.all()

D.

app.route()

38 $What is a 'room' in Socket.IO primarily used for?$

A.

Storing data permanently

B.

Partitioning connected clients into groups

C.

Authentication

D.

Logging errors

39 $If you want to persist login state across server restarts effectively, which session store should you use with express-session ?$

A.

MemoryStore

B.

An array variable

C.

A compatible store like Redis or MongoDB

D.

A text file

40 $What is the output of typeof req.session inside a route handler when using express-session ?$

A.

undefined

B.

string

C.

object

D.

function

41 $Which middleware would you use to log details of every incoming request (method, URL, etc.)?$

A.

morgan

B.

express-session

C.

helmet

D.

cookie-parser

42 $In a WebSocket connection, what property indicates the current state (connecting, open, closing, closed)?$

A.

socket.status

B.

socket.readyState

C.

socket.connStatus

D.

socket.state

43 $When initializing express-session, what does the saveUninitialized: false option do?$

A.

It deletes the session immediately

B.

It saves empty sessions to the store

C.

It saves the session without a cookie

D.

It prevents saving a session to the store if it is new but not modified

44 $Which function allows multiple middleware functions to be applied to a single route?$

A.

Using app.double()

B.

They cannot be chained

C.

Passing them as comma-separated arguments to the route method

D.

Creating a loop

45 $In Socket.IO, socket.id represents:$

A.

The IP address

B.

The user's database ID

C.

A unique identifier for the socket session

D.

The port number

46 $If you wish to send binary data (like an image) via ws library, what type of data should you pass to .send() ?$

A.

A Boolean

B.

A Buffer or ArrayBuffer

C.

A JSON string

D.

An Object

47 $What is the purpose of the 'secret' used in session middleware?$

A.

To encrypt the database connection

B.

To sign the session ID cookie to prevent tampering

C.

To hide the server IP

D.

To authenticate users

48 $Can middleware modify the req and res objects?$

A.

Yes, middleware can add properties or methods to them

B.

No, they are read-only

C.

Only req can be modified

D.

Only res can be modified

49 $In a Chat Server, why would you store socket.id mapped to a username ?$

A.

To prevent the user from logging out

B.

To enable private messaging functionality

C.

To increase download speed

D.

To use less memory

50 $What happens if you attempt to use req.body without installing and using a body-parsing middleware (like express.json())?$

A.

It will contain the raw stream

B.

req.body will be undefined

C.

It will work automatically

D.

The server will crash

Unit 3 - Practice Quiz