Pydantic Fabricated

A Python package that provides a metaclass for fabricating subclasses from dictionaries inside Pydantic models. This library seamlessly integrates with Pydantic's type system to enable dynamic object creation based on type definitions.

Installation

pip install pydantic-fabricated

Features

• Dynamic object creation from type definitions
• Seamless integration with Pydantic models
• Type-safe parameter validation
• Support for JSON serialization/deserialization
• Discriminated unions for type-safe polymorphism

Quick Start

Here's a simple example of how to use Pydantic Fabricated:

import os

from pydantic_settings import BaseSettings, SettingsConfigDict

from pydantic_fabricated import PydanticFabricated


# Define a base class using the metaclass
class Shape(metaclass=PydanticFabricated):
    pass


# Define concrete implementations
class Circle(Shape):
    def __init__(self, radius: float):
        self.radius = radius


class Rectangle(Shape):
    def __init__(self, width: float, height: float):
        self.width = width
        self.height = height


# Create instances using the fabricate_from_type method
circle = Shape.fabricate_from_type('Circle', {'radius': 5.0})
rectangle = Shape.fabricate_from_type('Rectangle', {'width': 10.0, 'height': 20.0})


# Or use with Pydantic Settings
class Settings(BaseSettings):
    model_config = SettingsConfigDict(env_prefix='my_prefix_')

    shape: Shape


os.environ['MY_PREFIX_SHAPE'] = r'{"type": "Circle", "radius": 5.0}'
settings = Settings()

Requirements

• Python ≥ 3.13
• Pydantic ≥ 2.11.9

License

Apache License 2.0

Links

• GitHub Repository
• Documentation

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

Additional Documentation

• Development Guide
• Changelog