Wsrtjtyk

I have two models,

class Core:



    def logo_path(instance, filename):

        pattern = re.compile(r's+')

        filename = re.sub(pattern, '', filename)

        return 'images/core/logos/core_{0}/{1}'.format(instance.pk, filename)



    name = models.CharField(db_index=True, max_length=255)

    logo = models.ImageField(upload_to=logo_path, blank=True, null=True)

and

class CoreRoom(Room):

    core = models.ForeignKey(Core, on_delete=models.CASCADE, null=True)

    logo_url = models.CharField(max_length=1024, null=True)

I want to populate the logo_url in the CoreRoom object with the path to the logo in the Core object.
How do I do this?

I doubt this is needed as . you can always access it using my_core_room.core.logo.url, but the easiest way would be to override the .save() method of your CoreRoom model:

class CoreRoom(Room):

   ...

   def save(self, *args, **kwargs):

       self.logo_url = self.core.logo.url

       super(CoreRoom, self).save(*args, **kwargs)

logo_url model field can be converted to property method as well, because, it is not necessary to save logo url information as it is already stored in DB. For example:

class CoreRoom(Room):

     core = models.ForeignKey(Core, on_delete=models.CASCADE, null=True)

     # remove logo url model field



     @property

     def logo_url(self):

          return self.core.logo.url