Django - creating custom .save() for modelformset_factory - django

Question

If I create a formset using modelformset_factory like this:
IngredientFormSet = modelformset_factory(RecipeIngredients, form=RecipeIngredientsForm)
formset = IngredientFormSet(request.POST)
and my form looks like this
class RecipeIngredientsForm(forms.ModelForm):
Ingredient = forms.CharField(max_length= 100)
class Meta:
model = RecipeIngredients
exclude = ('weightmetric','recipe')
Where would I put my custom .save() method? Would I put it under the RecipeIngredientsForm?
[a potential solution]
In your view do something like this:
if formset.is_valid():
for form in formset:
obj = form.save(commit=False) #obj = RecipeIngredient model object
try:
ingredient_in_db = Ingredient.objects.get(name = form.cleaned_data.get('ingredientform'))
except:
ingredient_in_db = None
if ingredient_in_db:
obj.ingredient = ingredient_in_db
else:
new_ingredient = Ingredient.objects.create(name = form.cleaned_data.get('ingredientform'))
obj.ingredient = new_ingredient
obj.recipe = recipeobj
obj.save()
Incidentally, I think this method would also allow me to do a custom .save(), given that I take each form in the formset and do a form.save(commit= False) on it. It was easier though, to just do it in my view, since I needed access to the recipe object.

Answer 1

I'm not sure of the best way to override the existing save() method on the BaseModelForm. My guess is that you actually would want to either:
Create your own field that has it's own to_python() method which will take the text and find/create the associated object.
class IngredientField(forms.CharField):
def to_python(self, value):
# Lookup model or create new one
ingredient = models.Ingredient.objects.get(name=value)
if not ingredient:
ingredient = models.Ingredient.create(name=value)
return ingredient
Use save(commit=False) on the formset, do the ingredient lookup/creation, and then commit afterwards