Session expiry behavior in Django - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to set a session variable in Django.

Django

request.session[[1]] = 'user123'

Drag options to blanks, or click blank then click option'

A'user_id'

Buser_id

C'session_key'

Dsession_key

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting to use quotes around the session key name.

Using variable names without quotes which causes errors.

Session keys must be strings, so quotes are needed around 'user_id'.

2fill in blank

medium

Complete the code to set the session expiry time to 5 minutes.

Django

request.session.set_expiry([1])

Drag options to blanks, or click blank then click option'

A'5 minutes'

B5

C300

D60

Attempts:

3 left

💡 Hint

Common Mistakes

Passing minutes directly instead of seconds.

Using a string instead of an integer.

The set_expiry method expects seconds, so 5 minutes is 300 seconds.

3fill in blank

hard

Fix the error in the code to clear the session data properly.

Django

request.session.[1]()

Drag options to blanks, or click blank then click option'

Aflush

Bclear

Cdelete

Dremove

Attempts:

3 left

💡 Hint

Common Mistakes

Using clear() which only removes data but keeps the session cookie.

Using non-existent methods like delete() or remove().

The flush() method clears the session data and deletes the session cookie.

4fill in blank

hard

Fill both blanks to check if the session has expired and then set a new expiry.

Django

if request.session.get_expiry_age() [1] 0:
    request.session.set_expiry([2])

Drag options to blanks, or click blank then click option'

A>

B<

C300

D0

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong comparison operator causing logic errors.

Setting expiry time to zero which means session expires immediately.

Check if expiry age is less than 0 (expired), then set expiry to 300 seconds (5 minutes).

5fill in blank

hard

Fill all three blanks to create a session dictionary comprehension that stores user IDs with expiry times greater than 10 minutes.

Django

active_sessions = {user: request.session.get_expiry_age() [1] 600 for user in users if request.session.get_expiry_age() [2] 600 and request.session.exists([3])}

Drag options to blanks, or click blank then click option'

A>

B<

C'session_key'

Duser

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing up comparison operators causing wrong filtering.

Using a string literal instead of the user variable for session key.

The comprehension filters users with expiry age greater than 600 seconds (10 minutes) and checks if the session exists for that user key.

Practice

1. What does the set_expiry() method do in Django sessions?

easy

A. It encrypts the session data.

B. It deletes the session immediately.

C. It sets how long a user's session will last before expiring.

D. It creates a new session key for the user.

Solution

1. Step 1: Understand the purpose of set_expiry()

   This method controls the lifetime of a session by setting its expiration time.

2. Step 2: Compare options with the method's function

   Only It sets how long a user's session will last before expiring. correctly describes that set_expiry() sets how long the session lasts before it expires.

3. Final Answer:

   It sets how long a user's session will last before expiring. -> Option C

4. Quick Check:

   Session expiry time = set_expiry() [OK]

Hint: Remember: set_expiry controls session lifetime [OK]

Common Mistakes:

• Confusing set_expiry() with session deletion
• Thinking it creates or encrypts sessions
• Assuming it resets session data

2. Which of the following is the correct way to set a session to expire in 300 seconds in Django?

easy

A. request.session.expire(300)

B. request.session.set_expiry(300)

C. request.set_expiry(300)

D. session.set_expiry_time(300)

Solution

1. Step 1: Identify the correct method and object

   The method set_expiry() is called on request.session to set expiry time.

2. Step 2: Check syntax correctness

   request.session.set_expiry(300) uses the correct method and object: request.session.set_expiry(300). Other options use incorrect method names or objects.

3. Final Answer:

   request.session.set_expiry(300) -> Option B

4. Quick Check:

   Correct method call = request.session.set_expiry(300) [OK]

Hint: Call set_expiry on request.session, not request [OK]

Common Mistakes:

• Calling set_expiry on request instead of request.session
• Using wrong method names like expire or set_expiry_time
• Missing parentheses or wrong argument

3. Given this code snippet, what will be the session expiry behavior?

request.session.set_expiry(0)

medium

A. The session expiry will use the default global timeout.

B. The session will never expire.

C. The session will expire after 0 seconds immediately.

D. The session will expire when the browser is closed.

Solution

1. Step 1: Understand what passing 0 to set_expiry means

   In Django, setting expiry to 0 means the session expires when the browser closes (a browser-length session).

2. Step 2: Compare with other options

   The session will expire when the browser is closed. matches this behavior. The session will never expire. is false because 0 does not mean never expire. The session will expire after 0 seconds immediately. is incorrect because it does not expire immediately. The session expiry will use the default global timeout. is incorrect because default timeout is overridden.

3. Final Answer:

   The session will expire when the browser is closed. -> Option D

4. Quick Check:

   set_expiry(0) = expire on browser close [OK]

Hint: 0 means expire on browser close, not immediately [OK]

Common Mistakes:

• Thinking 0 means no expiry
• Assuming immediate expiry at 0 seconds
• Confusing with default session timeout

4. What is wrong with this code snippet if the goal is to set the session to expire after 10 minutes?

request.session.set_expiry = 600

medium

A. It assigns a value to the method instead of calling it.

B. The expiry time should be in milliseconds, not seconds.

C. The session object does not have set_expiry attribute.

D. The value 600 is too large and causes an error.

Solution

1. Step 1: Analyze the code syntax

   The code assigns 600 to set_expiry instead of calling it as a method with parentheses.

2. Step 2: Understand correct usage

   The correct usage is request.session.set_expiry(600) to call the method and set expiry time.

3. Final Answer:

   It assigns a value to the method instead of calling it. -> Option A

4. Quick Check:

   Use parentheses to call set_expiry() [OK]

Hint: Use parentheses to call set_expiry(), not assignment [OK]

Common Mistakes:

• Assigning value instead of calling method
• Confusing seconds with milliseconds
• Believing 600 causes error due to size

5. You want a session to expire after 5 minutes but also want to keep the session alive if the user is active. Which approach correctly achieves this in Django?

hard

A. Set set_expiry(300) on every user request to reset expiry time.

B. Set set_expiry(300) once when the session is created only.

C. Set set_expiry(0) to expire on browser close and ignore activity.

D. Do not set expiry; rely on default session timeout.

Solution

1. Step 1: Understand session expiry reset behavior

   Calling set_expiry(300) on every request resets the expiry countdown, keeping session alive if user is active.

2. Step 2: Evaluate other options

   Set set_expiry(300) once when the session is created only. sets expiry once, so session expires after 5 minutes regardless of activity. Set set_expiry(0) to expire on browser close and ignore activity. expires on browser close, ignoring time. Do not set expiry; rely on default session timeout. uses default timeout, no control.

3. Final Answer:

   Set set_expiry(300) on every user request to reset expiry time. -> Option A

4. Quick Check:

   Reset expiry on each request = Set set_expiry(300) on every user request to reset expiry time. [OK]

Hint: Reset expiry timer on each request to keep session alive [OK]

Common Mistakes:

• Setting expiry only once at session creation
• Using 0 expiry which ignores time
• Relying on default timeout without control