FlexField

FlexField is a JSON field validated against a JSON Schema. It is the foundation for structured, editor-configurable content: the schema is defined in your model, the data is validated on save and in forms.

from blueprint.fields import FlexField


class Article(models.Model):
    content = FlexField(
        {
            "type": "object",
            "properties": {
                "heading": {"type": "string"},
                "blocks": {
                    "type": "array",
                    "items": {
                        "type": "object",
                        "properties": {
                            "type": {"enum": ["text", "image"]},
                            "text": {"type": "string"},
                        },
                    },
                },
            },
            "required": ["heading"],
        }
    )

Validation

The schema is checked when the field is instantiated — an invalid schema raises ValueError. Values are validated with a JSONSchemaValidator attached to the field, so both full_clean() and form validation reject non-conforming data. If you pass your own validators, they run in addition to the schema validation — custom validators never replace it.

article = Article(content={"heading": "Hello"})   # valid
article.full_clean()                              # passes

article.content = {"text": "No heading"}
article.full_clean()                              # ValidationError

Migrations

The schema is part of the field's serialized form (deconstruct()), so it ends up in your migrations. Changing the schema therefore produces a migration — intended, because the schema shapes what your application accepts. Schema changes are not applied retroactively to existing rows; write a data migration when you tighten a schema.