forms - How to use the request in a ModelForm in Django

Question

I would like to make a queryset where the current user is used as a filter in a ModelForm:

class BookSubmitForm(ModelForm):
    book = forms.ModelChoiceField(queryset=Book.objects.filter(owner=request.user),)
...

Does Django pass the request to the form? Is it good practice? How can I use the request? (of course the name request is not defined)

Edit:

I tried another solution which is to call the form in the view passing it the request:

form = BookSubmitForm(request)

and then in the form I use this:

class BookSubmitForm(ModelForm):
    def __init__(self, request, *args, **kwargs):
        super(BookSubmitForm, self).__init__(*args, **kwargs)
        self.fields["library"].queryset = Library.objects.filter(owner=request.user)

It works and the code is in the form. Now I'm not sure it's the best solution, could it be improved?

Answer 1

No, the request is not passed to the ModelForm. You'll need to do something like this in your view:

form = BookSubmitForm()
form.fields['book'].queryset = Book.objects.filter(owner=request.user)
# pass form to template, etc

As you said, it's often cleaner to encapsulate this in the Form object, particularly if you have several fields that will need filtered querysets. To do this, override the forms's __init__() and have it accept a kwarg of request:

class BookSubmitForm(ModelForm):
    def __init__(self, *args, **kwargs):
        self.request = kwargs.pop("request")
        super(BookSubmitForm, self).__init__(*args, **kwargs)
        self.fields["book"].queryset = Book.objects.filter(owner=self.request.user)
        self.fields["whatever"].queryset = WhateverModel.objects.filter(user=self.request.user)

Then just pass request whenever you instantiate BookSubmitForm in your view:

def book_submit(request):
    if request.method == "POST":
        form = BookSubmitForm(request.POST, request=request)
        # do whatever
    else:
        form = BookSubmitForm(request=request)
    # render form, etc