Django: save model object of a ModelForm - django

Question

I have a ModelForm:
class UploadForm(forms.ModelForm):
class Meta:
model = Image
fields = ['image']
which is based on model Image
class Image(models.Model):
def content_file_name(instance, filename):
return filename
name = models.CharField(max_length=50)
image = models.ImageField(upload_to=content_file_name)
user = models.ForeignKey(MyUser, related_name='image')
In views.py, I try to save the image name and user object (from session) along with the uploaded image to database.
form1 = UploadForm(request.POST, request.FILES)
if form1.is_valid():
image = request.FILES['image'] # image is of UploadedFile class
form1.Meta.model.name = image.name
form1.Meta.model.user = get_object_or_404(MyUser,username=request.session['user'])
form1.save()
return render(request, '16_upload01.html', context)
Problem is only the uploaded image gets saved. Error message in browser:
IntegrityError at /competition-big/big1/upload
comp_app_image.user_id may not be NULL
I confirmed this by checking on SQL command:
INSERT INTO "comp_app_image" ("name", "image", "user_id") VALUES ('', 'grey-160-100_1.png', None)
I figure that image name and user are not bounded to form1. But how can I achieve that?
EDIT
After some digging, I know I messed up with above code. Now I changed my code to this:
if form1.is_valid():
form1.cleaned_data['user'] = get_object_or_404(MyUser, username=request.session['user'])
form1.save()
But I still get null user_id error.
EDIT 2
Thanks Jacinda. Now I get this cleaner code:
if form1.is_valid():
form1.cleaned_data['user'] = request.user
form1.save()
But error null user_id remains.

Answer 1

If this form can only be accessed by a logged in user, use the login_required decorator, and you should always redirect after a POST. You should also read this section in the ModelForms documentation; which describes how to properly use a model form that has limited fields.
from django.shortcuts import redirect
from django.contrib.auth.decorators import login_required
#login_required
def your_view(request):
form1 = UploadForm(request.POST, request.FILES)
if form1.is_valid():
image = request.FILES['image'] # image is of UploadedFile class
obj = form1.save(commit=False)
obj.name = image.name
obj.user = request.user
obj.save()
return redirect('your-view-name')
else:
return render(request, 'form.html', {'form': form1})

Answer 2

I think your issue is probably this line:
form1.Meta.model.user = get_object_or_404(MyUser,username=request.session['user'])
When I try and use your syntax (using the Django default django.contrib.auth) I get a KeyError on 'user'.
What I've always done when I need information about the user associated with a request is this:
username = request.user.username
Reference: https://docs.djangoproject.com/en/dev/ref/request-response/#django.http.HttpRequest.user
Of course, this will only work if your users are required to be logged in to upload images.