ModelForms & Custom Validation Clean Methods

1. Deep Architecture

Django forms process raw request inputs into typed Python values via the is_valid() call. The validation process runs individual field checks, executes custom field-level clean_<fieldname> methods, and finally runs the form-level clean() method for cross-field checks.

2. The Feynman Gatekeeper

[KNOWLEDGE CHECK] Trace the flow of data inside a Django form from request.POST until it is saved inside cleaned_data.

3. The Code

from django import forms
from sanjaya_core.models import Video

class VideoUploadForm(forms.ModelForm):
    class Meta:
        model = Video
        fields = ['title', 'file_path']

    def clean_title(self):
        title = self.cleaned_data.get('title')
        if len(title) < 5:
            raise forms.ValidationError("Title must be at least 5 characters.")
        return title

4. The Funnel

Stat Level-Up: Validation Gatekeeper (Lvl 1).
Sanjaya Integration: Reject invalid video format paths early, preventing downstream processing failures.