[Python] Django downloads binary file from FastAPI (MinIO presigned URL), but the file is...

I'm using Django (frontend) and FastAPI (backend) with MinIO as file storage. My setup:

• FastAPI generates a presigned MinIO download_url for the file.
• Django fetches metadata via FastAPI, then downloads the file using requests.get(download_url, stream=True) and returns it with StreamingHttpResponse.

Here is my Django view for downloading the file:

from django.http import StreamingHttpResponse, Http404
from django.utils.encoding import smart_str
from urllib.parse import quote
import requests

def download_file(request, file_id):
print(f'file_id = {file_id}')
try:
url = f"http://89.150.34.163:8000/api/v1/student/download/{file_id}"
response = requests.get(url)
if response.status_code != 200:
raise Http404("Файл не найден")

json_data = response.json()
download_url = json_data.get("download_url")
original_filename = json_data.get("original_filename", f"file_{file_id}")
print(f'filename: {original_filename}')

if not download_url:
raise Http404("Ссылка на скачивание отсутствует")

file_response = requests.get(download_url, stream=True)
if file_response.status_code != 200:
raise Http404("Ошибка при скачивании файла")
filename_ascii = smart_str(original_filename)
filename_utf8 = quote(original_filename)

response = StreamingHttpResponse(
streaming_content=file_response.iter_content(chunk_size=8192),
content_type=file_response.headers.get("Content-Type", "application/octet-stream")
)
response['Content-Disposition'] = (
f'attachment; filename="{filename_ascii}"; '
f"filename*=UTF-8''{filename_utf8}"
)

return response

except Exception as e:
print(f"Ошибка при скачивании: {e}")
raise Http404("Ошибка при скачивании файла")


When I download the file via browser (pasting the download_url directly), it works perfectly — correct filename and contents.

But when I download it through Django the file has a corrupted name (e.g. download, загруженное, etc.). The .docx file becomes corrupted and can't be opened in MS Word (even though the byte size is correct — e.g., 23526 bytes).

I tried using smart_str and quote() to handle Unicode/cyrillic filenames and validating that FastAPI returns the correct download_url and original_filename.

Any suggestions? Is there a better way to proxy a file from a presigned MinIO URL through Django without corruption?

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