Setting model user to current user when using inlineformset_factory in Django

Question

I've hit a roadblock that I've spent hours trying to overcome, and I would appreciate some guidance.

I have two models: Listings and Addresses, with the following structure:

class Listings(models.Model):
    created_date = models.DateTimeField(auto_now_add=True)
    pub_date = models.DateTimeField(auto_now_add=True)
    address = models.ForeignKey(Addresses)
    user = models.ForeignKey(User, on_delete=models.CASCADE)
    is_active = models.BooleanField(default=1)

class Addresses(models.Model):
    address1 = models.CharField(max_length=100)
    address2 = models.CharField(max_length=100)
    address3 = models.CharField(max_length=100)
    address4 = models.CharField(max_length=100)
    postcode = models.CharField(max_length=8)

I also have these:

class AddressForm(ModelForm):
    class Meta:
        model = Addresses
        fields = ['address1', 'address2', 'address3', 'address4', 'postcode']

class ListingForm(ModelForm):
    class Meta:
        model = Listings
        fields = ['user']

I'm trying to create a form which will add a new listing, however the only information to be entered are the fields in the Addresses model. When the form is submitted, I need a new Listings object and a new Addresses object to be created, but the Listings object must have the 'user' foreign key equal to the id of the current logged-in user.

This is the view:

@login_required(login_url='share:login_view',          redirect_field_name='share:addlisting')
def addlisting(request):

    ListingInlineFormSet = inlineformset_factory(Addresses, Listings, form=ListingForm, can_delete=False, extra=1)

    if request.method == 'POST':

        address_form = AddressForm(request.POST)
        if address_form.is_valid():
            new_address = address_form.save()
            listing_formset = ListingInlineFormSet(request.POST, request.FILES, instance=new_address)

            if listing_formset.is_valid():
                listing_formset.save()
                return HttpResponseRedirect(reverse('/listing_added/'))

    else:
        address_form = AddressForm()
        listing_formset = ListingInlineFormSet()

    return render(request, 'share/addlisting.html', {
        "address_form": address_form,
        "listing_formset": listing_formset,
    })

In its current state, I get a form containing all the address fields, plus a drop-down user field. When the form is submitted, it creates a new listing with two foreign keys: one for the chosen user, and another for the new address that has just been created. This end result is what I want. HOWEVER, I don't want there to be a drop-down user field in the form - I need the user to be set to the current user. I tried using "exclude = ['user']" in the ListingForm class instead of "fields = ['user']", but this had the result of creating a new address without creating a listing to go with it. So all I got was a new address, and no listing.

What am I doing wrong? I would be so grateful for a solution to this, as I've been banging my head against a wall for a very long time!

Answer 1

In this case I wouldn't use a formset at all. If you need to collect user information to create the new listing, use a single ListingForm and AddressForm, save the new address, and then save the ListingForm with commit=False, assign the user and address to it, and then save the instance.

@login_required(login_url='share:login_view', redirect_field_name='share:addlisting')
def addlisting(request):
    if request.method == 'POST':
        address_form = AddressForm(request.POST, prefix="address")
        listing_form = ListingForm(request.POST, prefix="listing")
        if address_form.is_valid() and listing_form.is_valid():
            new_address = address_form.save()
            new_listing = listing_form.save(commit=False)
            new_listing.address = new_address
            new_listing.user = request.user
            new_listing.save()
            return HttpResponseRedirect(reverse('/listing_added/'))
    else:
        address_form = AddressForm(prefix="address")
        listing_form = ListingForm(prefix="listing")
    return render(request, 'share/addlisting.html', {
        "address_form": address_form,
        "listing_form": listing_form
    })

If you ever have a many-to-many relationship on Listings you'll need to explicitly save those after saving the instance, as discussed here: https://docs.djangoproject.com/en/1.10/topics/forms/modelforms/#the-save-method