django-dynamic-storage 0.1.5

Use and choose storages at runtime based on your logic for each model FileField instance separately.

django-dynamic-storage

Have you ever wanted not to store every instance of FileFileds or ImageFileds of a model in one storage or one bucket of a storage?

Now you can, because I wanted that for my project.

prerequisites:

If your django version is earlier than 3.1 (<=3.0) then your database should be PostgreSQL otherwise you are good to go.

Usage:

pip install django-dynamic-storage

in storage.py:

from dynamic_storage.storage import DynamicStorageMixin

@deconstructible
class MyDynamicStorage(DynamicStorageMixin, AnyStorage):
	def init_params(self) -> dict:
		"""
		here you should return a dictionary of key value pairs that 
		later django-dynamic-storage could instantiate this class with
		"""
		return {"named_param1": self.named_param1, "named_param2": self.named_param2, ...}

AnyStorage can be a storage that you define yourself or import from django-storages.

in models.py:

from dynamic_storage.models import DynamicFileField, DynamicImageField

class MyModel(models.Model):
	"""
	DynamicFileField and DynamicImageField accept any options that django's native FileField and ImageField accept
	"""
	file = DynamicFileField()
	image = DynamicWagtailImageField()

Now your logic to take control of the storage where your content is going to be saved to:

obj = MyModel(file=file, image=image)
obj.file.destination_storage = MyDynamicStorage(named_param1="something", named_param2="another_thing")
obj.image.destination_storage = MyDynamicStorage(named_param1="foo", named_param2="bar")
obj.save()

or using signals:

(new to signals? learn how to connect them)

from dynamic_storage.signals import pre_dynamic_file_save

@receiver(pre_dynamic_file_save, sender=models.MyModel)
def decide_the_storage_to_save(
instance
, field_file
, to_storage
, *args,
 **kwargs
):
    if not to_storage:
    	# destination_storage is not set, so we set it here
        field_file.destination_storage = MyDynamicStorage(named_param1="something", named_param2="another_thing")
    elif to_storage == wrong_storage:
		# override the destination_storage set earlier
		field_file.destination_storage = MyAnotherDynamicStorage(named_param1="foo", named_param2="bar")

Performance penalty?!

Not even a bit!

HOW?

We are just using the django's built in JsonField instead of CharField  to store more data (init_params output) in addition to the path to the file.

so no extra queries, no extra steps, no performance penalty.