Using Django's signals

 Using Django's signals

In Django, we can use signals to decouple application logic and perform tasks when certain events occur. Signals allow us to define sender/receiver relationships and execute code when a signal is sent. Here's an example signal that sends an email when a new blog post is created:

python

from django.db.models.signals import post_save

from django.dispatch import receiver

from django.core.mail import send_mail

from .models import Post

@receiver(post_save, sender=Post)

def send_new_post_notification(sender, instance, **kwargs):

    subject = f'New blog post: {instance.title}'

    message = f'A new blog post was created with the title "{instance.title}".'

    recipient_list = ['admin@example.com']

    send_mail(subject, message, 'admin@example.com', recipient_list)

In this example, we define a send_new_post_notification receiver function that sends an email when a Post object is saved. We use the post_save signal and specify the sender as the Post model. We define the subject, message, and recipient_list variables for the email and use Django's send_mail function to send the email.

We can connect our receiver function to the signal by importing it in our app's apps.py file and connecting it in the ready method:

python

from django.apps import AppConfig

class MyAppConfig(AppConfig):

    default_auto_field = 'django.db.models.BigAutoField'

    name = 'myapp'

    def ready(self):

        import myapp.signals

In this example, we import our signal receiver function and connect it to the signal in the ready method of our app configuration class.