Regarding FileResponse and compressed file objects. Bug?

[Zachary J.]

Consider this situation:

import gzip
from django.http import FileResponse


def some_request(request):
    return FileResponse(
        gzip.open('/path/to/filename.gz'),
        content_type="text/plain",
        filename="filename.txt",
        as_attachment=True
    )

This theoretically should work fine, because why shouldn't it?

However the code that determines the Content-Length is as such (https://github.com/django/django/blob/c1c68d1ac0f0d50eb37df32892b132f31a1179da/django/http/response.py#L425):

if os.path.isabs(filename):
    self['Content-Length'] = os.path.getsize(filelike.name)
elif hasattr(filelike, 'getbuffer'):
    self['Content-Length'] = filelike.getbuffer().nbytes

Which gets the file size of the compressed gzip file. (the elif branch is never run) That means that the Content-Length will be shorter than the uncompressed content that I am actually sending.

My current "dumb" solution is as such:

from io import BytesIO
import shutil


def some_request(request):
    buff = BytesIO()
    with gzip.open('/path/to/filename.gz') as g:

        shutil.copyfileobj(g, buff)
    buff.seek(0)

    return FileResponse(

        buff,
        content_type="text/plain",
        filename="filename.txt",
        as_attachment=True
    )

This reads all the uncompressed content into a separate file-like object that does not have the original file name information. Which forces FileResponse to run the elif branch. Is there a better way to do things?