Django File upload issues

handler.py

from django.core.files.uploadhandler import FileUploadHandler
from django.core.files.uploadedfile import UploadedFile
from .. import cloudstorage as gcs

class GoogleCloudStorageUploadHandler(FileUploadHandler):
    def __init__(self, request=None):
        self.file_name = None
        self.content_type = None
        self.content_length = None
        self.charset = None
        self.request = request

        self.file_size = None
        self.bucket = '/path-to-my-bucket'
        self.gcs_file = None

    def receive_data_chunk(self, raw_data, start):
        self.gcs_file.write(raw_data)

        return None

    def file_complete(self, file_size):
        self.file_size = file_size
        self.gcs_file.close()

        return UploadedFile(
            file = self.gcs_file,
            name = self.file_name,
            content_type = self.content_type,
            size = self.file_size,
            charset = self.charset
        )

    def new_file(self, field_name, file_name, content_type, content_length, charset=None):
        self.field_name = field_name
        self.file_name = file_name
        self.content_type = content_type
        self.content_length = content_length
        self.charset = charset
        self.gcs_file = gcs.open(self.bucket + '/' + file_name, 'w', content_type=content_type)

models.py

from django.db import models
from django import forms

MEDIA_TYPES = (
    ('audio', 'audio'),
    ('video', 'video'),
    ('text', 'text'),
    ('image', 'image'),
)

# Used for uploading media that forms part of a story
class Media(models.Model):
    title = models.CharField(max_length=100)
    type = models.CharField(max_length=5, choices=MEDIA_TYPES)
    content = models.TextField()
    date_created = models.DateTimeField(auto_now_add=True)
    file = models.FileField()

# Used to convert the media model to a form in the cms
class MediaForm(forms.ModelForm):
    class Meta:
        model = Media
        # Don't show the date created field because we want that to be set automatically
        exclude = ('date_created', 'content',)

settings.py

# ...

# File uploads
FILE_UPLOAD_HANDLERS = (
    'modules.django_gcs_upload_handler.GoogleCloudStorageUploadHandler',
)

# ...

views.py

from django.http import HttpResponse
from django.shortcuts import redirect, render
from django.contrib.auth.decorators import login_required
from django.contrib.auth import logout as logout_user
from django.contrib import messages
from django.core.urlresolvers import reverse

from api.models import Media
from api.models import MediaForm

from modules import cloudstorage as gcs

# ....

# Render the add/edit media form or handle saving it
@login_required
def media_add_or_edit(request, id=False):
    # Is it a POST request, i.e is the form being submitted
    if request.method == 'POST':
        # Pass the form all the HTTP POST data
        form = MediaForm(request.POST, request.FILES)

        # Run through any validation rules we have
        if form.is_valid():
            # Save the form data to the db
            form.save()

            # Show a success message to the user
            message_suffix = 'added!' if id is False else 'edited'
            messages.success(request, 'Media succesfully %s' % message_suffix)

            # Redirect them back to the media home page
            return redirect('media-home')

    # Were we passed the id? i.e are we editing an object, if so get it to pass to the template
    if id is not False:
        media = Media.objects.get(id=id)
        form = form if request.method == 'POST' else MediaForm(instance=media)
        template_data = {'form': form, 'title': media.title}

    # If not we must be adding new media as we have no id in the URL
    else:
        form = form if request.method == 'POST' else MediaForm()
        template_data = {'form': form, 'title': 'Add Media'}

    return render(request, 'cms/form.html', template_data)

# ...