Actions triggered by field change in Django

Question

How do I have actions occur when a field gets changed in one of my models? In this particular case, I have this model:

class Game(models.Model):
    STATE_C         


        

Answer 1

It has been answered, but here's an example of using signals, post_init and post_save.

from django.db.models.signals import post_save, post_init

class MyModel(models.Model):
    state = models.IntegerField()
    previous_state = None

    @staticmethod
    def post_save(sender, **kwargs):
        instance = kwargs.get('instance')
        created = kwargs.get('created')
        if instance.previous_state != instance.state or created:
            do_something_with_state_change()

    @staticmethod
    def remember_state(sender, **kwargs):
        instance = kwargs.get('instance')
        instance.previous_state = instance.state

post_save.connect(MyModel.post_save, sender=MyModel)
post_init.connect(MyModel.remember_state, sender=MyModel)