[DJUGL] Signals and AppConfig

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SIGNALS AND APPCONFIG DJUGL October 6, 2015

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@anabalica

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Let’s get schwifty with !

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from django.db.models.signals import post_save from django.dispatch import receiver from myapp.models import MyModel @receiver(post_save, sender=MyModel) def my_handler(sender, **kwargs): pass # my_app/signals.py

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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): pass # my_app/signals.py

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Django<1.7? make sure that the module it’s in gets imported early on so that the signal handling gets registered before any signals need to be sent

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Django<1.7? make sure that the module it’s in gets imported early on so that the signal handling gets registered before any signals need to be sent

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Django<1.7? this makes your app’s models.py a good place to put registration of signal handlers

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from django.db import models from my_app import signals class MyModel(models.Model): pass # my_app/models.py

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CIRCULAR IMPORTS

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from my_app import signals # my_app/__init__.py

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AppConfig to the rescue

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AppConfig is a registry of installed apps and available models

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>>> from django.apps import apps >>> apps.get_app_config('admin').verbose_name 'Admin'

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from django.apps import AppConfig class RickNMortyConfig(AppConfig): name = "rick_n_morty" verbose_name = "Rick and Morty" # my_app/apps.py

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INSTALLED_APPS = [ "my_app.apps.RickNMortyConfig", # ... ] # settings.py or default_app_config = "my_app.apps.RickNMortyConfig" # my_app/__init__.py

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from django.apps import AppConfig class RickNMortyConfig(AppConfig): name = "rick_n_morty" verbose_name = "Rick and Morty” def ready(self): from my_app import signals # my_app/apps.py

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• Loads the settings • Sets up logging • Initializes the application registry

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• Imports each item from INSTALLED_APPS • Imports the models submodule if exists • Runs the ready() method of each app config

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