[Django]-Having Django serve downloadable files

A “download” is simply an HTTP header change.

See http://docs.djangoproject.com/en/dev/ref/request-response/#telling-the-browser-to-treat-the-response-as-a-file-attachment for how to respond with a download.

You only need one URL definition for "/download".

The request’s GET or POST dictionary will have the "f=somefile.txt" information.

Your view function will simply merge the base path with the “f” value, open the file, create and return a response object. It should be less than 12 lines of code.

For a very simple but not efficient or scalable solution, you can just use the built in django serve view. This is excellent for quick prototypes or one-off work, but as has been mentioned throughout this question, you should use something like apache or nginx in production.

from django.views.static import serve
filepath = '/some/path/to/local/file.txt'
return serve(request, os.path.basename(filepath), os.path.dirname(filepath))

S.Lott has the “good”/simple solution, and elo80ka has the “best”/efficient solution. Here is a “better”/middle solution – no server setup, but more efficient for large files than the naive fix:

http://djangosnippets.org/snippets/365/

Basically, Django still handles serving the file but does not load the whole thing into memory at once. This allows your server to (slowly) serve a big file without ramping up the memory usage.

Again, S.Lott’s X-SendFile is still better for larger files. But if you can’t or don’t want to bother with that, then this middle solution will gain you better efficiency without the hassle.

Just mentioning the FileResponse object available in Django 1.10

Edit: Just ran into my own answer while searching for an easy way to stream files via Django, so here is a more complete example (to future me). It assumes that the FileField name is imported_file

views.py

from django.views.generic.detail import DetailView   
from django.http import FileResponse
class BaseFileDownloadView(DetailView):
  def get(self, request, *args, **kwargs):
    filename=self.kwargs.get('filename', None)
    if filename is None:
      raise ValueError("Found empty filename")
    some_file = self.model.objects.get(imported_file=filename)
    response = FileResponse(some_file.imported_file, content_type="text/csv")
    # https://docs.djangoproject.com/en/1.11/howto/outputting-csv/#streaming-large-csv-files
    response['Content-Disposition'] = 'attachment; filename="%s"'%filename
    return response

class SomeFileDownloadView(BaseFileDownloadView):
    model = SomeModel

urls.py

...
url(r'^somefile/(?P<filename>[-\w_\\-\\.]+)$', views.SomeFileDownloadView.as_view(), name='somefile-download'),
...

Tried @Rocketmonkeys solution but downloaded files were being stored as *.bin and given random names. That’s not fine of course. Adding another line from @elo80ka solved the problem.
Here is the code I’m using now:

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

filename = "/home/stackoverflow-addict/private-folder(not-p**n)/image.jpg"
wrapper = FileWrapper(file(filename))
response = HttpResponse(wrapper, content_type='text/plain')
response['Content-Disposition'] = 'attachment; filename=%s' % os.path.basename(filename)
response['Content-Length'] = os.path.getsize(filename)
return response

You can now store files in a private directory (not inside /media nor /public_html) and expose them via django to certain users or under certain circumstances.
Hope it helps.

Thanks to @elo80ka, @S.Lott and @Rocketmonkeys for the answers, got the perfect solution combining all of them =)

It was mentioned above that the mod_xsendfile method does not allow for non-ASCII characters in filenames.

For this reason, I have a patch available for mod_xsendfile that will allow any file to be sent, as long as the name is url encoded, and the additional header:

X-SendFile-Encoding: url

Is sent as well.

http://ben.timby.com/?p=149

Try: https://pypi.python.org/pypi/django-sendfile/

“Abstraction to offload file uploads to web-server (e.g. Apache with mod_xsendfile) once Django has checked permissions etc.”

You should use sendfile apis given by popular servers like apache or nginx in production. For many years I was using the sendfile api of these servers for protecting files. Then created a simple middleware based django app for this purpose suitable for both development & production purposes. You can access the source code here.

UPDATE: in new version python provider uses django FileResponse if available and also adds support for many server implementations from lighthttp, caddy to hiawatha

Usage

pip install django-fileprovider

• add fileprovider app to INSTALLED_APPS settings,
• add fileprovider.middleware.FileProviderMiddleware to MIDDLEWARE_CLASSES settings
• set FILEPROVIDER_NAME settings to nginx or apache in production, by default it is python for development purpose.

in your class-based or function views, set the response header X-File value to the absolute path of the file. For example:

def hello(request):
   # code to check or protect the file from unauthorized access
   response = HttpResponse()  
   response['X-File'] = '/absolute/path/to/file'  
   return response

django-fileprovider implemented in a way that your code will need only minimum modification.

Nginx configuration

To protect file from direct access you can set the configuration as

location /files/ {
  internal;
  root   /home/sideffect0/secret_files/;
}

Here nginx sets a location url /files/ only access internaly, if you are using above configuration you can set X-File as:

response['X-File'] = '/files/filename.extension'

By doing this with nginx configuration, the file will be protected & also you can control the file from django views

def qrcodesave(request): 
    import urllib2;   
    url ="http://chart.apis.google.com/chart?cht=qr&chs=300x300&chl=s&chld=H|0"; 
    opener = urllib2.urlopen(url);  
    content_type = "application/octet-stream"
    response = HttpResponse(opener.read(), content_type=content_type)
    response["Content-Disposition"]= "attachment; filename=aktel.png"
    return response 

Django recommend that you use another server to serve static media (another server running on the same machine is fine.) They recommend the use of such servers as lighttp.

This is very simple to set up. However. if ‘somefile.txt’ is generated on request (content is dynamic) then you may want django to serve it.

Django Docs – Static Files

Another project to have a look at: http://readthedocs.org/docs/django-private-files/en/latest/usage.html
Looks promissing, haven’t tested it myself yet tho.

Basically the project abstracts the mod_xsendfile configuration and allows you to do things like:

from django.db import models
from django.contrib.auth.models import User
from private_files import PrivateFileField

def is_owner(request, instance):
    return (not request.user.is_anonymous()) and request.user.is_authenticated and
                   instance.owner.pk = request.user.pk

class FileSubmission(models.Model):
    description = models.CharField("description", max_length = 200)
        owner = models.ForeignKey(User)
    uploaded_file = PrivateFileField("file", upload_to = 'uploads', condition = is_owner)

I have faced the same problem more then once and so implemented using xsendfile module and auth view decorators the django-filelibrary. Feel free to use it as inspiration for your own solution.

https://github.com/danielsokolowski/django-filelibrary

Providing protected access to static html folder using https://github.com/johnsensible/django-sendfile: https://gist.github.com/iutinvg/9907731

I did a project on this. You can look at my github repo:

https://github.com/nishant-boro/django-rest-framework-download-expert

This module provides a simple way to serve files for download in django rest framework using Apache module Xsendfile. It also has an additional feature of serving downloads only to users belonging to a particular group