Signals in django

A (very) short introduction on the use of signals in django.

Transcript

1. Signals in Django Roberto Bampi: - Enrolled at UniTN - Work at MPBA (FBK)
2. What they are “In a nutshell, signals allow certain senders to notify a set of receivers that some action has taken place. They’re especially useful when many pieces of code may be interested in the same events.” http://docs.djangoproject.com
3. How they work (recieving) Listening to a signal: Signal.connect(receiver[, sender=None, weak=True, dispatch_uid=None]) reciever can be any python function or method. Listeners in action: from django.db.models.signals import pre_save from django.dispatch import receiver from myapp.models import MyModel @receiver(pre_save, sender=MyModel) def my_handler(sender, **kwargs): ... Signals are synchronous: Request is therefore blocked until each signal has finished processing. Do not use them to perform long calculations or I/O.
4. How they work (creating and sending) Defining signals: import django.dispatch pizza_done = django.dispatch.Signal(providing_args=["toppings", "size"]) Sending a signal: class PizzaStore(object): ... def send_pizza(self, toppings, size): pizza_done.send(sender=self, toppings=toppings, size=size) ...
5. Thanks for watching the awful presentation ...
6. Contacts: bampi.roberto@gmail.com github.com/gigaroby