django view Session ID -missing for user not logged in

Question

On my current project I want the user to be able to fill in forms without having to sign up first (to make them more likely to use the service).

On the below view I'm trying to either save the registered user with the form data, or if the user isn't registered save the Session ID as a temporary user id.

However when I try to use the session ID it returns none. I'm not sure why the data is missing? (Session have the default django setup in apps and middleware as per the docs). Note when a user is logged in it seem to have a user id but not when no user is logged in.

View:

class ServiceTypeView(CreateView):
    form_class = ServiceTypeForm
    template_name = "standard_form.html"
    success_url = '/'

    def form_valid(self, form):
        if self.request.user.is_authenticated():
            form.instance.user = self.request.user
        else:
            form.instance.temp_user = self.request.session.session_key
        super().form_valid(form)
        online_account = form.cleaned_data['online_account']
        if online_account:
            return redirect('../online')
        else:
            return redirect('../address')

Model:

class EUser(models.Model):

    supplier1 = models.OneToOneField(SupplierAccount)
    supplier2 = models.OneToOneField(SupplierAccount)
    supplier3 = models.OneToOneField(SupplierAccount)
    online_account = models.BooleanField()
    address = models.OneToOneField(Address, null=True)
    temp_user = models.CharField(max_length=255, null=True)
    user = models.OneToOneField(settings.AUTH_USER_MODEL, null=True, default=None)


class SupplierAccount(models.Model):
    supplier = models.ForeignKey(Supplier)
    username = models.CharField(max_length=255)
    password = models.CharField(max_length=255)

Form:

class ServiceTypeForm(forms.ModelForm):
    # BOOL_CHOICES = ((False, 'No'), (True, 'Yes'))

    # online_account = forms.BooleanField(widget=forms.RadioSelect(choices=BOOL_CHOICES))

    def __init__(self, *args, **kwargs):
        super(ServiceTypeForm, self).__init__(*args, **kwargs)
        self.fields['service_type'].initial = 'D'

    class Meta:
        model = EUser
        fields = ('service_type', 'online_account')

Answer 1

The session key will exist if there is data set in the session dictionary already. Logged in users have a session key because Django stores authentication related data in the session by default, so a key will always be assigned because of that.

You can ensure that a key always exists by tossing some data into the session storage before trying to get the key.