How do I POST hidden FileFields in Django template?

I'm attempting to deal with uploading files in Django and I've hit a snag. My goal is to create a form which allows users to upload text and file data, preview that input, and then publish it.

I put all the logic in a single view with multiple templates associated with the various submit buttons. I didn't want to save all of the instances and then create a custom manager for published posts. However, perhaps I should do that.

My issue is that my file formset isn't working properly. When I just submitted the data, without previewing it, it was fine. But, once, I started POSTing back forth to different templates, it stopped working. I know that you want to HttpResponseRedirect after a POST, but i figured my method was fine in this case. I honestly have no clue.

Here's my view logic

def post(request):
    page="post"
#check if user has already posted and if so, direct them to their account post history page
try:
    user=User.objects.get(pk=request.user.id)
except User.DoesNotExist:   
    user=''
if user:
    try:
        post=user.post_set.all()[0]
        return HttpResponseRedirect("/profile/post/")

    #Here a user who has not posted is shown a form to do so
    except IndexError:
        postform=PostForm(prefix="post")
        PhotoFormSet=modelformset_factory(Post_Photo,exclude=('post',), extra=4, max_num=4)
        photo_formset=PhotoFormSet(queryset=Post_Photo.objects.filter(post__lt=0),prefix="phot开发者_Python百科os")  #lt 0 is a hack to return an empty query set, so that other photos aren't returned with the form

#Here an anonymous user sees the form, though they can't successfully submit
else:
    postform=PostForm(prefix="post")
    PhotoFormSet=modelformset_factory(Post_Photo,exclude=('post',), extra=4, max_num=4)
    photo_formset=PhotoFormSet(queryset=Post_Photo.objects.filter(post__lt=0),prefix="photos")


if request.method=='POST' and user and request.POST.get('preview'):     
    photo_formset=PhotoFormSet(request.POST, request.FILES, prefix="photos")
    postform=PostForm(request.POST,prefix="post")
    if postform.is_valid() and photo_formset.is_valid():
        post=postform.save(commit=False)
        photos=photo_formset.save(commit=False)
        return render_to_response('website/preview_post.html', {'page':page,'post':post,'photos':photos,'photo_formset':photo_formset}, context_instance=RequestContext(request))
    else:
        return HttpResponse('error test')


if request.method=='POST' and user and request.POST.get('edit'):
    photo_formset=PhotoFormSet(request.POST, request.FILES, prefix="photos")
    postform=PostForm(request.POST,prefix="post")
    neighborhood=request.POST.get('post-neighborhood','')
    if postform.is_valid() and photo_formset.is_valid():
        return render_to_response('website/post_upload.html', {'page':page, 'neighborhood':neighborhood,'postform':postform, 'photo_formset':photo_formset}, context_instance=RequestContext(request))
    else:
        return HttpResponse(postform.errors)


if request.method=='POST' and user and request.POST.get('publish'):     
    photo_formset=PhotoFormSet(request.POST, request.FILES, prefix="photos")
    postform=PostForm(request.POST,prefix="post")
    if postform.is_valid() and photo_formset.is_valid():
        post=postform.save(commit=False)
        post.user=user
        post.save()
        photos=photo_formset.save(commit=False)
        for photo in photos:
            photo.post=post
            photo.save()
        return HttpResponse('/post_upload/?success=1')
    else:
        return HttpResponse('%s' %postform.errors)
return render_to_response("website/post_upload.html", {'page':page,'postform':postform,'photo_formset':photo_formset}, context_instance=RequestContext(request))        

In my preview template, I include hidden inputs that are then POSTed either back to the edit page or published. My photo_formset is contained in a div with display:none property so it's invisible.

When I POST from the edit page, the hidden text inputs go through but the FILE inputs do not. What can I do about this?

Thanks

My guess is that the file inputs are not being passed into step 2, because <input type="file"> elements don't contain data and don't get prepopulated. <input type="file"> are always blank on load.

You can't share file data between browser refreshes, unless you encode the data into a form text element and decode it or store it in the session.

It's a browser security measure.

Check my answer here:

Resubmitting Image in ImageField after Validation Error in Django

I'd store the saved file information in the session and pull it back out in step 3 of your form.

1. Submit # store filename
2. Preview
3. Submit # pull filename

Or, you could set up an ajax preview or such?