create formset data with dicts, and modelformset data with models

formset_data_factory.py

from django.forms import formsets, model_to_dict
from django.http.request import QueryDict


def formset_data_factory(formset_class, dicts, extra_fields=None):
    data = QueryDict(mutable=True)
    form = formset_class.form
    prefix = (form.prefix or formset_class.get_default_prefix()) + '-'

    fields = form.declared_fields.viewkeys() | form.base_fields.viewkeys()
    if extra_fields:
        fields |= set(extra_fields)
    if formset_class.can_delete:
        fields.add(formsets.DELETION_FIELD_NAME)
    if formset_class.can_order:
        fields.add(formsets.ORDERING_FIELD_NAME)

    data[prefix + formsets.TOTAL_FORM_COUNT] = len(dicts)
    data[prefix + formsets.INITIAL_FORM_COUNT] = 0

    for i, d in enumerate(dicts):
        i_prefix = prefix + '{}-'.format(i)
        d.setdefault(formsets.ORDERING_FIELD_NAME, i)
        for field in fields:
            data[i_prefix + field] = d.get(field, '')

    return data


def modelformset_data_factory(modelformset_class, objects, deleted_objects=None, extra_fields=None):
    form_meta = modelformset_class.form._meta
    pk_field = form_meta.model._meta.pk.name
    fields = (set(form_meta.fields) | {pk_field}) if form_meta.fields else None
    exclude = (set(form_meta.exclude) - {pk_field}) if form_meta.exclude else None
    dicts = [dict(model_to_dict(obj, fields, exclude), **{formsets.ORDERING_FIELD_NAME: i}) for i, obj in enumerate(objects)]
    if deleted_objects:
        dicts += [dict(model_to_dict(obj, fields, exclude), **{formsets.DELETION_FIELD_NAME: 'on'}) for obj in deleted_objects]
    if extra_fields:
        extra_fields = set(extra_fields) + pk_field
    else:
        extra_fields = (pk_field,)
    return formset_data_factory(modelformset_class, dicts, extra_fields)


def inlineformset_data_factory(inlineformset_class, objects, deleted_objects=None, extra_fields=None):
    fk_field = inlineformset_class.fk.name
    if extra_fields:
        extra_fields = set(extra_fields) + fk_field
    else:
        extra_fields = (fk_field,)
    return modelformset_data_factory(inlineformset_class, objects, deleted_objects, extra_fields)