Django signals for decoupled event handling

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                  from django.db.models.signals import post_save
from django.dispatch import receiver
from django.core.mail import send_mail
from .models import User, Profile


@receiver(post_save, sender=User)
def create_user_profile(sender, instance, created, **kwargs):
    """Create a profile automatically when a user is created."""
    if created:
        Profile.objects.create(user=instance)


@receiver(post_save, sender=User)
def send_welcome_email(sender, instance, created, **kwargs):
    """Send welcome email to new users."""
    if created:
        send_mail(
            subject='Welcome to our platform!',
            message=f'Hi {instance.first_name}, welcome aboard!',
            from_email='noreply@example.com',
            recipient_list=[instance.email],
            fail_silently=True,
        )

                  from django.apps import AppConfig


class AccountsConfig(AppConfig):
    default_auto_field = 'django.db.models.BigAutoField'
    name = 'accounts'

    def ready(self):
        import accounts.signals  # noqa

Signals allow different parts of the application to respond to model events without tight coupling. I use post_save for actions after an object is created or updated, like sending notifications or updating related records. The @receiver decorator is cleaner than connect() calls. I'm careful to check created flag to distinguish creation from updates. For heavy operations, I dispatch to Celery tasks instead of blocking the request. Signals are powerful but can make code harder to trace, so I document them well and use sparingly for cross-app coordination.

Priya Sharma

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Django signals for decoupled event handling

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