Generating file to download with Django

Question

Is it possible to make a zip archive and offer it to download, but still not save a file to the hard drive?

There is a code example at http://djangosnippets.org/snippets/365/ — dmitri, May 06 '11 at 01:14

score 118 · Answer 1 · edited Jul 27 '16 at 09:16

118

To trigger a download you need to set Content-Disposition header:

from django.http import HttpResponse
from wsgiref.util import FileWrapper

# generate the file
response = HttpResponse(FileWrapper(myfile.getvalue()), content_type='application/zip')
response['Content-Disposition'] = 'attachment; filename=myfile.zip'
return response

If you don't want the file on disk you need to use StringIO

import cStringIO as StringIO

myfile = StringIO.StringIO()
while not_finished:
    # generate chunk
    myfile.write(chunk)

Optionally you can set Content-Length header as well:

response['Content-Length'] = myfile.tell()

edited Jul 27 '16 at 09:16

Oli

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answered May 26 '09 at 05:53

muhuk

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I think Content-Length might happen automatically with Django middleware – andrewrk Jun 18 '10 at 00:28
4

Using this example downloads a file that is always empty, any ideas? – camelCase May 22 '13 at 23:30
3

As @eleaz28 said, it was creating blank files in my case too. I just removed the `FileWrapper`, and it worked. – Seb D. May 05 '15 at 15:57
This answer doesn't work with Django 1.9: see this: http://stackoverflow.com/a/35485073/375966 – Afshin Mehrabani Feb 18 '16 at 15:06
I know this post is old now, but @eleaz28, i was having the same trouble, i solved it by using fileIO.seek(0). – Dennis Jan 24 '17 at 17:25
@AfshinMehrabani, to only download file in django 1.10 there's a documentation now: https://docs.djangoproject.com/en/1.10/ref/request-response/#telling-the-browser-to-treat-the-response-as-a-file-attachment – Dennis Jan 24 '17 at 17:25
2

I opened my file in read mode then file.getvalue() is giving attribute error : TextIOWrapper has no attribute getValue . – Anonymous Apr 13 '18 at 20:41
New versions of Django provide FileResponse which is a wrapper around wsgiref FileWrapper but generates streaming http response: https://docs.djangoproject.com/en/3.0/ref/request-response/#fileresponse-objects – Pratyush Apr 24 '20 at 05:57

score 28 · Answer 2 · answered May 25 '09 at 22:42

28

You'll be happier creating a temporary file. This saves a lot of memory. When you have more than one or two users concurrently, you'll find the memory saving is very, very important.

You can, however, write to a StringIO object.

>>> import zipfile
>>> import StringIO
>>> buffer= StringIO.StringIO()
>>> z= zipfile.ZipFile( buffer, "w" )
>>> z.write( "idletest" )
>>> z.close()
>>> len(buffer.getvalue())
778

The "buffer" object is file-like with a 778 byte ZIP archive.

answered May 25 '09 at 22:42

S.Lott

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Good point about saving memory. But if using a temporary file, where would you put the code to delete it? – andrewrk Jun 18 '10 at 00:28
@superjoe30: periodical cleanup jobs. Django already has an admin command that must be run periodically to remove old sessions. – S.Lott Jun 18 '10 at 02:51
@superjoe30 that's what /tmp is for :) – aehlke Jan 16 '14 at 23:25
@S.Lott Is it possible to serve the created file (z in in your example) using mod x-sendfile? – Amir Afianian Jan 24 '16 at 11:48

score 11 · Answer 3 · edited Jan 26 '18 at 10:42

11

Why not make a tar file instead? Like so:

def downloadLogs(req, dir):
    response = HttpResponse(content_type='application/x-gzip')
    response['Content-Disposition'] = 'attachment; filename=download.tar.gz'
    tarred = tarfile.open(fileobj=response, mode='w:gz')
    tarred.add(dir)
    tarred.close()

    return response

edited Jan 26 '18 at 10:42

Guillaume Lebreton

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answered Sep 08 '11 at 20:12

Roshan

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For newer version of Django, you should have `content_type=` instead of `mimetype=` – Guillaume Lebreton Jan 26 '18 at 08:14

Soviut · Answer 4 · 2009-05-25T22:35:13.580

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Yes, you can use the zipfile module, zlib module or other compression modules to create a zip archive in memory. You can make your view write the zip archive to the HttpResponse object that the Django view returns instead of sending a context to a template. Lastly, you'll need to set the mimetype to the appropriate format to tell the browser to treat the response as a file.

edited May 25 '09 at 22:35

answered May 25 '09 at 22:29

Soviut

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score 7 · Answer 5 · edited Jun 20 '20 at 09:12

7

models.py

from django.db import models

class PageHeader(models.Model):
    image = models.ImageField(upload_to='uploads')

views.py

from django.http import HttpResponse
from StringIO import StringIO
from models import *
import os, mimetypes, urllib

def random_header_image(request):
    header = PageHeader.objects.order_by('?')[0]
    image = StringIO(file(header.image.path, "rb").read())
    mimetype = mimetypes.guess_type(os.path.basename(header.image.name))[0]

    return HttpResponse(image.read(), mimetype=mimetype)

edited Jun 20 '20 at 09:12

Community

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answered Aug 03 '11 at 07:24

Ryan Anguiano

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Looks unsafe to create in-memory string of image size. – dhill Feb 27 '17 at 12:45

score 5 · Answer 6 · answered Jul 29 '16 at 13:10

5

def download_zip(request,file_name):
    filePath = '<path>/'+file_name
    fsock = open(file_name_with_path,"rb")
    response = HttpResponse(fsock, content_type='application/zip')
    response['Content-Disposition'] = 'attachment; filename=myfile.zip'
    return response

You can replace zip and content type as per your requirement.

answered Jul 29 '16 at 13:10

Kamesh Jungi

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You meant `fsock = open(filePath,"rb")` – stelios Aug 22 '18 at 12:48

score 4 · Answer 7 · answered Nov 03 '16 at 01:04

Same with in memory tgz archive:

import tarfile
from io import BytesIO


def serve_file(request):
    out = BytesIO()
    tar = tarfile.open(mode = "w:gz", fileobj = out)
    data = 'lala'.encode('utf-8')
    file = BytesIO(data)
    info = tarfile.TarInfo(name="1.txt")
    info.size = len(data)
    tar.addfile(tarinfo=info, fileobj=file)
    tar.close()

    response = HttpResponse(out.getvalue(), content_type='application/tgz')
    response['Content-Disposition'] = 'attachment; filename=myfile.tgz'
    return response

Generating file to download with Django

7 Answers7

models.py

views.py

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