Django - Passing parameters to inline formset

Question

I am using inlineformset_factory to create fields for a many to many relationship between Clients and Sessions, with an intermediary Attendance model.

I have the following in my views file:

AttendanceFormset = inlineformset_factory(
    Session,
    Attendance,
    formset=BaseAttendanceFormSet,
    exclude=('user'),
    extra=1,
    max_num=10,
    )

session = Session(user=request.user)
formset = AttendanceFormset(request.POST, instance=session)

And, as I needed to override one of the form fields, I added the following to the formset base class:

class BaseAttendanceFormSet(BaseFormSet):

    def add_fields(self, form, index):
        super(BaseAttendanceFormSet, self).add_fields(form, index)
        form.fields['client'] = forms.ModelChoiceField(
                queryset=Client.objects.filter(user=2))

Now, the form works correctly, but I need to pass a value into the formset so that I can filter the clients displayed based the current user rather than just using the id 2.

Can anyone help?

Any advice appreciated.

Thanks.

EDIT

For anyone reading, this is what worked for me:

def get_field_qs(field, **kwargs):
        if field.name == 'client':
            return forms.ModelChoiceField(queryset=Client.objects.filter(user=request.user))
        return field.formfield(**kwargs)

Answer 1

How about utilizing the inlineformset_factory's formfield_callback param instead of providing a formset ? Provide a callable which in turns returns the field which should be used in the form.

Form fields callback gets as 1st parameter the field, and **kwargs for optional params (e.g: widget).

For example (using request.user for the filter, replace with another if needed:

def my_view(request):
    #some setup code here

    def get_field_qs(field, **kwargs):
        formfield = field.formfield(**kwargs)
        if field.name == 'client':
            formfield.queryset = formfield.queryset.filter(user=request.user)
        return formfield

    AttendanceFormset = inlineformset_factory(
        ...
        formfield_callback=get_field_qs
        ...
    )

    formset = AttendanceFormset(request.POST, instance=session)

To better understand it, see the usage of formfield_callback in Django's FormSet code.