django-treeform

from django import forms
from django_treeform import TreeForm, SequenceNode, Sequence

class CharacteristicForm(TreeForm):
    id = forms.IntegerField()
    name = forms.CharField()
    rating = forms.CharField()

class PersonForm(TreeForm):
    id = forms.IntegerField()
    name = forms.CharField()
    phone = forms.CharField()
    Charecteristics = SequenceNode(CharacteristicForm)

params = [{
    "id": 1,
    "name": "abc",
    "phone": "12345",
    "Charecteristics": [
        {
            "id": 1,
            "name": "Good Looking",
            "rating": "Average",
        },
        {
            "id": 2,
            "name": "Smart",
            "rating": "Excellent",
        }
    ]
},
{
    "id": 2,
    "name": "abc",
    "phone": "12345",
    "Charecteristics": [
        {
            "id": 1,
            "name": "Good Looking",
            "rating": "Average",
        },
        {
            "id": 2,
            "name": "Smart",
            "rating": "Excellent",
        }
    ]
}]
form = Sequence(PersonForm)(params)
print(form.is_valid()) # => True

more nested forms

from django import forms
from django_treeform import SequenceNode, TreeForm

class ItemForm(forms.Form):
    name = forms.CharField()


class NestedForm(TreeForm):
    class a(TreeForm):
        class b(TreeForm):
            class c(TreeForm):
                class d(TreeForm):
                    class e(TreeForm):
                        items = SequenceNode(ItemForm)

params = {
    "a": {"b": {"c": {"d": {"e": {"items": [{"name": "A"}, {"name": "B"}]}}}}}
}
formlike = NestedForm(params)

print(formlike.is_valid()) # => True
expected = {'a': {'b': {'c': {'d': {'e': {'items': [{'name': 'A'}, {'name': 'B'}]}}}}}}
assert formlike.cleaned_data == expected
assert formlike.errors == {'a': {'b': {'c': {'d': {'e': {'items': [{}, {}]}}}}}}

custom validation

class PointForm(forms.Form):
    x = forms.IntegerField()
    y = forms.IntegerField()


class PointPairForm(TreeForm):
    left = Node(PointForm)
    right = Node(PointForm)

    def clean(self):
        if self.has_error():
            return
        if self.cleaned_data["left"]["x"] < self.cleaned_data["right"]["x"]:
            raise forms.ValidationError("oops")

params = {"left": {"x": 10, "y": 20}, "right": {"x": 20, "y": "20"}}
formlike = PointPairForm(params)
print(formlike.is_valid() # => False
print(formlike.errors) # => {"left": {}, "right": {}, "__all__": ["oops"]}