Connecting signal handlers in Django - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to import the Django signal dispatcher.

Django

from django.dispatch import [1]

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

ASignal

Breceiver

Cconnect

Dsend

Attempts:

3 left

💡 Hint

Common Mistakes

Importing 'Signal' instead of 'receiver'.

Trying to import 'connect' which is a method, not an import.

Using 'send' which is a method to send signals, not to connect handlers.

The receiver decorator is imported from django.dispatch to connect signal handlers.

2fill in blank

medium

Complete the code to connect a signal handler to the post_save signal of a model.

Django

@receiver([1], sender=MyModel)
def my_handler(sender, instance, **kwargs):
    pass

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

Apre_delete

Bpre_save

Cpost_save

Dpost_delete

Attempts:

3 left

💡 Hint

Common Mistakes

Using pre_save which triggers before saving.

Using delete signals instead of save signals.

Not specifying the correct signal name.

The post_save signal is sent after a model instance is saved, so the handler should listen to it.

3fill in blank

hard

Fix the error in the signal handler connection by completing the missing import.

Django

from django.db.models.signals import [1]

@receiver(post_save, sender=User)
def user_saved(sender, instance, **kwargs):
    print('User saved!')

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

Apre_save

Bpost_delete

Cpre_delete

Dpost_save

Attempts:

3 left

💡 Hint

Common Mistakes

Importing the wrong signal.

Not importing the signal at all.

Importing signals from the wrong module.

The post_save signal must be imported from django.db.models.signals to be used in the handler.

4fill in blank

hard

Fill both blanks to connect a handler to the pre_delete signal for the Article model.

Django

from django.db.models.signals import [1]

@receiver([2], sender=Article)
def before_delete(sender, instance, **kwargs):
    print('Article will be deleted')

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

Apre_delete

Bpost_save

Cpre_save

Dpost_delete

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing different signals in import and decorator.

Using save signals instead of delete signals.

Forgetting to import the signal.

Both the import and the decorator must use the pre_delete signal to connect the handler properly.

5fill in blank

hard

Fill all three blanks to create a signal handler that listens to post_save for Profile and prints the instance's username.

Django

from django.db.models.signals import [1]
from django.dispatch import [2]

@[2]([1], sender=Profile)
def profile_saved(sender, instance, **kwargs):
    print(f"Saved profile for {instance.username}")

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

Apost_save

Breceiver

Cpre_save

Dpost_delete

Attempts:

3 left

💡 Hint

Common Mistakes

Using different decorators in import and usage.

Importing the wrong signal.

Not matching the signal in import and decorator.

The post_save signal is imported and used with the receiver decorator to connect the handler.