In this tutorial we will learn about the signal in django.

from django.db.models.signals import post_save,post_delete
from django.dispatch import receiver
#you need to import Location,Activities,Employee,Notification,FCMDevice models
@receiver(post_delete, sender=Location)
@receiver(post_delete, sender=Activities)
@receiver(post_delete, sender=Employee)
def delete_notification(sender, instance, **kwargs):
    Notification.objects.filter(table_uuid=instance.uuid).delete()
    devices = FCMDevice.objects.all()
    if devices:
        FCMDevice.objects.send_message(
            M(notification=n(title=f"{sender._meta.verbose_name} has been deleted.",
                             body=f"{sender._meta.verbose_name} with uuid {instance.uuid} deleted."))
        )


        
@receiver(post_save, sender=Location)
@receiver(post_save, sender=Activities)
@receiver(post_save, sender=Rate)
@receiver(post_save, sender=Employee)
@receiver(post_save, sender=Price)
@receiver(post_save, sender=Airlines)
@receiver(post_save, sender=FlightRecord)
@receiver(post_save, sender=CustomFlightRecord)
def create_notification(sender, instance, created, **kwargs):
    if sender._meta.verbose_name.lower() == "location":
        title = "New Location Added"
        description = "New location has been added by management team."
        image = "notification/location_icon.png"

    elif sender._meta.verbose_name.lower() == "activities":
        title = "New activities Added"
        description = f'New activities has been added by {instance.employee}.'
        image = instance.employee.profile