CODEWITHSUNDEEP
djangodjango-models
prauchfuss
prauchfuss

Reputation: 1970

Use method of model class within save method

I'm trying to override the save method of one of my models. Within that save method I would like to use another method of the model, like this:

class MyModel(models.Model):
    name = models.CharField(max_length=255)

    def do_something(self):
        pass

    def save(self,*args, **kwargs):
        self.do_something()
        super(MyModel, self).save(*args, **kwargs)

This doesn't work because when django executes the save, the object is a generic ModelBase class and not my subclass of ModeBase. So I get:

unbound method do_something() must be called with MyModel instance as first argument (got ModelBase instance instead)

What is the right way to do this?

Upvotes: 0

Views: 451

Answers (1)

Aleš Kotnik
Aleš Kotnik

Reputation: 2724

You should put args and kwargs to overridden save()method too:

class MyModel(models.Model):
    name = models.CharField(max_length=255)

    def do_something(self):
        pass

    def save(self, *args, **kwargs):
        self.do_something()
        super(MyModel, self).save(*args, **kwargs)

You also forgot self parameter in do_something()!

UPDATE

I don't quite understand your problem. If you want to call unbound method do_something, define it outside the class MyModel with one and just call it from save() like `do_something(self):

class MyModel(class.Model):
  def save(self, *args, **kwargs):
    do_something(self)
    super(MyModel, self).save(*args, **kwargs)

def do_someting(my_model_instance):
  assert isinstance(my_model_instance, MyModel)
  ...

Upvotes: 1

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