Storing and downloading files from Redis in Django Celery Queue - django

Question

I'm zipping a large number of files in my app, which leads to problems with performance. So now I've decided to zip files in a separate queue, store results in Redis and make available to user as soon as the process is done. I'm storing data in Redis to make it faster, and because I don't need files to be stored on server hard drive.
Here is my task.py:
#shared_task
def zip_files(filenames, key):
compression = zipfile.ZIP_STORED
s = BytesIO()
zf = zipfile.ZipFile(s, mode="w")
for fpath in filenames:
fdir, fname = os.path.split(fpath)
zf.write(fpath, fname, compress_type=compression)
zf.close()
caches['redis'].set(hash_key, {'file':s.getvalue()})
return hash_key
And then here is my simple download view:
def folder_cache(request, folder_hash):
cache_data = caches['redis'].get(folder_hash)
if cache_data:
response = FileResponse(cache_data['file'], content_type="application/x-zip-compressed")
response['Content-Disposition'] = 'attachment; filename=hello.zip'
response['Content-Length'] = len(cache_data['file'])
return response
return HttpResponse("Cache expired.")
Problem is that I can only download a part of the file, then the download is stopped by "Network connection was lost" message. The downloaded file seems to contain a set of numbers (not binary data). But I don't know, maybe I use FileResponse wrong? Or I need to serialize data before / after putting it to Redis cache?
I also tried same code in shell, it works when I use fopen and write data from Redis cache directly to server hard drive.

Answer 1

Finally, I found out that I only had to wrap file data into ContentFile class. So here is the latest working code:
def folder_cache(request, folder_hash):
cache_data = caches['redis'].get(folder_hash)
if cache_data:
if (cache_data['status'] == 'complete'):
...
response = FileResponse(ContentFile(cache_data['file']), content_type="application/x-zip-compressed")
response['Content-Disposition'] = 'attachment; filename={}'.format(filename)
response['Content-Length'] = len(cache_data['file'])
return response