Django - signals. Simple examples to start

Question

I am new to Django and I'm not able to understand how to work with Django signals. Can anyone please explain "Django signals" with simple examples?

Thanks in advance.

Answer 1

You can find very good content about django signals over Internet by doing very small research.

Here i will explain you very brief about Django signals.
What are Django signals?
Signals allow certain senders to notify a set of receivers that some action has taken place

Actions :

model's save() method is called.
django.db.models.signals.pre_save | post_save

model's delete() method is called.
django.db.models.signals.pre_delete | post_delete

ManyToManyField on a model is changed.
django.db.models.signals.m2m_changed

Django starts or finishes an HTTP request.
django.core.signals.request_started | request_finished

All signals are django.dispatch.Signal instances.

very basic example :

models.py

from django.db import models from django.db.models import signals  def create_customer(sender, instance, created, **kwargs):     print "Save is called"  class Customer(models.Model):     name = models.CharField(max_length=16)     description = models.CharField(max_length=32)  signals.post_save.connect(receiver=create_customer, sender=Customer) 

Shell

In [1]: obj = Customer(name='foo', description='foo in detail')  In [2]: obj.save() Save is called