Session vs cookie decision in PHP - Practice Questions

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output of this PHP code using sessions?

Consider this PHP code snippet that uses sessions to store a user's name. What will be printed?

PHP

<?php
session_start();
$_SESSION['user'] = 'Alice';
echo $_SESSION['user'];
?>

A Empty output

B user

C Alice

D Error: Undefined index

💡 Hint

Sessions store data on the server and can be accessed after starting the session.

The code starts a session and sets the 'user' key in the session array to 'Alice'. Then it prints that value, so the output is 'Alice'.

🧠 Conceptual

intermediate

When should you use cookies instead of sessions?

Which situation is best suited for using cookies rather than sessions?

A Keeping user preferences that persist after browser closes

B Storing sensitive user data securely on the server

C Storing large amounts of data for a user

D Sharing data between different users

💡 Hint

Think about where cookies and sessions store data and their lifetime.

Cookies are stored on the user's browser and can persist after closing it, making them good for preferences. Sessions store data on the server and usually expire when the browser closes.

❓ Predict Output

advanced

What error does this PHP code produce?

What error will this PHP code produce when trying to access a cookie that is not set?

PHP

<?php
echo $_COOKIE['theme'];
?>

A Fatal error: Undefined variable

B Notice: Undefined index 'theme'

C Empty string output

D No output, script stops

💡 Hint

Accessing an unset array key in PHP triggers a notice.

Trying to access a cookie key that does not exist causes a PHP notice about an undefined index.

🧠 Conceptual

advanced

Why are sessions more secure than cookies for sensitive data?

Choose the best reason why sessions are considered more secure than cookies for storing sensitive information.

A Sessions store data on the server, reducing exposure to client attacks

B Cookies automatically expire after 5 minutes

C Sessions store data on the client side encrypted

D Cookies cannot be accessed by JavaScript

💡 Hint

Think about where the data is stored and who can access it.

Sessions keep data on the server, so it is not exposed to the user's browser or potential attackers, unlike cookies which are stored on the client side.

🚀 Application

expert

How many items are stored in the session after this code runs?

Given the following PHP code, how many key-value pairs are stored in the session?

PHP

<?php
session_start();
$_SESSION['user'] = 'Bob';
$_SESSION['cart'] = ['apple', 'banana'];
unset($_SESSION['user']);
$_SESSION['logged_in'] = true;
?>

A 1

B 0

C 3

D 2

💡 Hint

Remember that unset removes a key from the session array.

The code sets 'user' and 'cart', then removes 'user', and adds 'logged_in'. So only 'cart' and 'logged_in' remain, totaling 2 items.