Django binary file download damaged in browsers

Question

I have an idea that after authentication / permissions, the file is stored in the FileField file.

from django.http import StreamingHttpResponse
from rest_framework import viewsets
from rest_framework.decorators import detail_route
from wsgiref.util import FileWrapper
import mimetypes
from myapp.models import MyModel

class ExampleViewSet(viewsets.ViewSet):
   # Normal crud (retrive, list, etc.)
   @detail_route(methods=['GET'])
   def download(self, *args, **kwargs):
        pk = self.request.parser_context['kwargs'].get('pk', None)
        if pk is None:
            raise exceptions.ParseError('no pk')
        instance = MyModel.objects.get(pk=pk)
        filename = instance.file_field.name.split('/')[-1]
        mime = mimetypes.guess_type(filename)[0]
        file = instance.file_field.file
        response = StreamingHttpResponse(
            FileWrapper(open(file, 'rb'), 10240))
        response['Content-Type'] = "{0}; charset=utf-8".format(mime)
        response['Content-Length'] = file.size
        response[
            'Content-Disposition'] = 'attachment; filename={0}'.format(filename)
        return response

The file itself is a 3.7MB file that was previously uploaded by the user. In the download directory, the file is 3.7MB and opens correctly. when downloading via a browser (Firefox or Chrome) the file has 7.0 MB and is damaged (does not have the correct header for jpegs, which should start with two specific bytes) when downloading from curl or wget, the file is 3.7 MB and opens correctly

Below is the result of twisting the response fields using curl -v

curl -v http://localhost:3000/api/school_admin/posters/7/download?token=ZXlKaGJHY2lPaUpJVXpVeE1pSXNJblI1Y0NJNklrcFhWQ0o5LmV5SndhR0Z6YUNJNkltSmpjbmx3ZEY5emFHRXlOVFlrSkRKaUpERXlKR2hzVlUxd2QyOWpTM1pMTnk1VlRuSXZPR1ZNVWs5aFJEVjBVbmR2V21FeVVGVlZiWGhxTTJWb1UzZFhla1JNU3k5RmFqZFRJaXdpY0hKdlptbHNaVjl3YXlJNk15d2laWGh3SWpveE5EY3lOalUyTWpFMGZRLmV6OGg5SWVwLUozYjdQcHJLVGJCZWlSSjJPN1JRdnItaFVuLVg0dmdLZGdtRGdQV0s2ZzkzdktialN2Uy1EVTVkM1hRc2hRZ3YxeVZmQlJhUDBBVlhB -o test.jpeg
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
  0     0    0     0    0     0      0      0 --:--:-- --:--:-- --:--:--     0*   Trying 127.0.0.1...
* Connected to localhost (127.0.0.1) port 3000 (#0)
> GET /api/school_admin/posters/7/download?token=ZXlKaGJHY2lPaUpJVXpVeE1pSXNJblI1Y0NJNklrcFhWQ0o5LmV5SndhR0Z6YUNJNkltSmpjbmx3ZEY5emFHRXlOVFlrSkRKaUpERXlKR2hzVlUxd2QyOWpTM1pMTnk1VlRuSXZPR1ZNVWs5aFJEVjBVbmR2V21FeVVGVlZiWGhxTTJWb1UzZFhla1JNU3k5RmFqZFRJaXdpY0hKdlptbHNaVjl3YXlJNk15d2laWGh3SWpveE5EY3lOalUyTWpFMGZRLmV6OGg5SWVwLUozYjdQcHJLVGJCZWlSSjJPN1JRdnItaFVuLVg0dmdLZGdtRGdQV0s2ZzkzdktialN2Uy1EVTVkM1hRc2hRZ3YxeVZmQlJhUDBBVlhB HTTP/1.1
> Host: localhost:3000
> User-Agent: curl/7.43.0
> Accept: */*
> 
< HTTP/1.1 200 OK
< date: Mon, 29 Aug 2016 18:31:30 GMT
< server: WSGIServer/0.2 CPython/3.4.3
< allow: GET, DELETE, HEAD, OPTIONS
< content-type: image/jpeg; charset=utf-8
< vary: Accept
< content-length: 3947925
< content-disposition: attachment; filename=poster_28F7bdD4caAbCc583831c9E7C9baDaEC88Ecbde6FBAA6aE71cAdC09fd8EFCF7BD515155bec1C3FC6f01c6FEf5Ba76e41952E_Colosseum_in_Rome_Italy_-_April_2007.jpg
< x-frame-options: SAMEORIGIN
< via: 1.1 fedora
< Connection: keep-alive
< 
{ [15913 bytes data]
100 3855k  100 3855k    0     0   141M      0 --:--:-- --:--:-- --:--:--  144M
* Connection #0 to host localhost left intact

Answer 1

, nginx + uwsgi. , "Hop-by-hop", django runningerver , . .

Answer 2

/ FTP ASCII . " ASCII" , . " " , . FTP- FTP-. , FTP- .

Here you should try binary data, as in ASCII terms.