[DJUGL] Signals and AppConfig

Transcript

1. SIGNALS AND APPCONFIG DJUGL October 6, 2015

2. @anabalica

3. Let’s get schwifty with !

4. 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

5. 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

6. 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

7. 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

8. Django<1.7? this makes your app’s models.py a good place to

   put registration of signal handlers

9. from django.db import models from my_app import signals class MyModel(models.Model):

   pass # my_app/models.py
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11. CIRCULAR IMPORTS

12. from my_app import signals # my_app/__init__.py

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14. AppConfig to the rescue

15. AppConfig is a registry of installed apps and available models

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

17. from django.apps import AppConfig class RickNMortyConfig(AppConfig): name = "rick_n_morty" verbose_name

    = "Rick and Morty" # my_app/apps.py

18. INSTALLED_APPS = [ "my_app.apps.RickNMortyConfig", # ... ] # settings.py or

    default_app_config = "my_app.apps.RickNMortyConfig" # my_app/__init__.py
19. None

20. 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

21. • Loads the settings • Sets up logging • Initializes

    the application registry

22. • Imports each item from INSTALLED_APPS • Imports the models

    submodule if exists • Runs the ready() method of each app config
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