Copy a File from one Model's FileField to another Model's FileField without reading it

Question

Let's say I have a model somewhat like this -

class Test(models.Model):
    some_file=FileField(upload_to='test_directory')

class TestTransfer(models.Model):
    transferred_file=FileField(upload_to='transfer_directory')

Now, I have already tried simple object to object copying like this:

transfer_object.transferred_file=test_object.some_file
transfer_object.save()

What the above code does not do is, it does not upload the file to transfer_directory. Since the file is huge, I don't want it to take up memory space and there are multiple files which I have to transfer.

I am using S3 as media storage if that's needed.

If there is some work around this problem, I would be content

Gasanov · Answer 1 · 2019-05-16T16:32:23.893

1

Yes, you have to create new file instead of just copy the path of old file. Since you are using S3 with django-storages, here's how you can do it:

from django.core.files.base import ContentFile
from django.core.files.storage import default_storage


new_file = ContentFile('')
new_file.name = os.path.basename(test_object.some_file.name)
transfer_object.transferred_file = new_file
transfer_object.save()

bucket = default_storage.bucket
original_file = default_storage.open(test_object.some_file.name)
destination_file = default_storage.open(transfer_object.transferred_file.name)
copy_source = {
    'Bucket': bucket.name,
    'Key': original_file.obj.key
}
bucket.copy(copy_source, destination_file.obj.key)

edited May 16 '19 at 16:32

answered May 16 '19 at 13:21

Gasanov

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yeah, that's something I already know. But, is there a way where I don't have to read the file cause the file is huge and I don't want it in my memory. – yadavankit May 16 '19 at 13:24
You didn't said that file is big or you don't want it in memory. – Gasanov May 16 '19 at 13:26
@yadavankit not exactly sure it will work with s3, but that is working fine on local server. – Gasanov May 16 '19 at 13:35
are you using `django-storages`? – Gasanov May 16 '19 at 13:52
Let us [continue this discussion in chat](https://chat.stackoverflow.com/rooms/193471/discussion-between-yadavankit-and-gasanov). – yadavankit May 16 '19 at 13:53
1

@yadavankit try this solution. – Gasanov May 16 '19 at 16:16
Does using default_storage.bucket.copy do the operation on the storage engine rather than in-memory? – Ahmad Oct 04 '22 at 08:56

Copy a File from one Model's FileField to another Model's FileField without reading it

1 Answers1