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I have a django model like this:


class Todo(models.Model):
    big_file = models.FileField(blank=True)
    status = models.PositiveSmallIntegerField(default=0)
    progress = models.IntegerField(default=0)

I'd like to do two operations:

  • first make an empty zipfile out of big_file (less important)
  • and then progressively add files into my zipfile (and save it iteratively)

The overall process would look like that:

from django.core.files.base import File
import io, zipfile

def generate_data(todo):
    io_bytes = io.BytesIO(b'')
    # 1. save an empty Zip archive:
    with zipfile.ZipFile(io_bytes, 'w') as zip_fd:
        todo.generated_data.save('heavy_file.zip', File(zip_fd))

    # 2. Progressively fill the Zip archive:
    with zipfile.ZipFile(io_bytes, 'w') zip_fd:
        for filename, data_bytes in long_iteration(todo):
            with zip_fd.open(filename, 'w') as in_zip:
                in_zip.write(data_bytes)
            if condition(something):
                todo.generated_data.save()  # that does not work
                todo.status = 1
                todo.progress = 123
                todo.save()
    todo.status = 2
    todo.save()

But I can't figure out the right filedescriptor / file-like object / Filepath / django-File object combination ... And it seems that in django I always have to save(filename, content). But my content could be Gigabytes, so it does not sound reasonable to store it all into a "content" variable?

10000days
  • 13
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1 Answers1

1

Ok I found following solution for myself; first create an empty file and then use the <my_file_field>.path attribute:


def generate_data(todo):
    # 1. save an empty Zip archive:
    todo.big_file.save('filename.zip', ContentFile(''))
    with zipfile.ZipFile(todo.big_file.path, 'w') as zip_fd:
        pass

    # 2. Progressively fill the Zip archive:
    with zipfile.ZipFile(todo.big_file.path, 'w') zip_fd:
        ... # do the stuff
10000days
  • 13
  • 3