django - Post request with multipart/form-data in appengine python not working

Question

I'm attempting to send a multipart post request from an appengine app to an external (django) api hosted on dotcloud. The request includes some text and a file (pdf) and is sent using the following code

from google.appengine.api import urlfetch
from poster.encode import multipart_encode
from libs.poster.streaminghttp import register_openers

register_openers()
file_data = self.request.POST['file_to_upload']
the_file = file_data
send_url = "http://127.0.0.1:8000/"
values = {
          'user_id' : '12341234',
          'the_file' : the_file
          }

data, headers = multipart_encode(values)
headers['User-Agent'] = 'Mozilla/4.0 (compatible; MSIE 5.5; Windows NT)'
data = str().join(data)
result = urlfetch.fetch(url=send_url, payload=data, method=urlfetch.POST, headers=headers)
logging.info(result.content)

When this method runs Appengine gives the following warning (I'm not sure if it's related to my issue)

Stripped prohibited headers from URLFetch request: ['Content-Length']

And Django sends through the following error

<class 'django.utils.datastructures.MultiValueDictKeyError'>"Key 'the_file' not found in <MultiValueDict: {}>"

The django code is pretty simple and works when I use the postman chrome extension to send a file.

@csrf_exempt
def index(request):
    try:
        user_id = request.POST["user_id"]
        the_file = request.FILES["the_file"]
        return HttpResponse("OK")
    except:
        return HttpResponse(sys.exc_info())

If I add

print request.POST.keys()

I get a dictionary containing user_id and the_file indicating that the file is not being sent as a file. if I do the same for FILES i.e.

print request.FILES.keys()    

I get en empty list [].

EDIT 1:

I've changed my question to implement the suggestion of someone1 however this still fails. I also included the headers addition recommended by the link Glenn sent, but no joy.

EDIT 2:

I've also tried sending the_file as variations of

the_file = file_data.file
the_file = file_data.file.read()

But I get the same error.

EDIT 3:

I've also tried editing my django app to

the_file = request.POST["the_file"]

However when I try to save the file locally with

path = default_storage.save(file_location, ContentFile(the_file.read()))

it fails with

<type 'exceptions.AttributeError'>'unicode' object has no attribute 'read'<traceback object at 0x101f10098>

similarly if I try access the_file.file (as I can access in my appengine app) it tells me

<type 'exceptions.AttributeError'>'unicode' object has no attribute 'file'<traceback object at 0x101f06d40>

Answer 1

Waitting for answers