What are Django signals and how can I use them effectively?

What are Django signals and how can I use them effectively?

Django signals allow certain senders to notify a set of receivers when some action has taken place. They are useful for decoupling applications.

Can you give me an example of a signal in Django?

Sure! A common example is the post_save signal, which is sent after a model's save() method is called. You can connect a receiver function to this signal to perform actions after saving an instance.

How do I connect a receiver to a signal?

You can use the @receiver decorator from django.dispatch to connect your receiver function to a signal. For example:

from django.db.models.signals import post_save
from django.dispatch import receiver

@receiver(post_save, sender=MyModel)
def my_handler(sender, instance, created, **kwargs):
    if created:
        print('A new instance was created!')

Are there any best practices for using signals?

Yes, it's best to keep signal handlers lightweight and avoid complex logic. Also, be cautious of circular dependencies and ensure that signals are registered in the right place.