maproxylib 0.1.1

Transparent access to nested objects/dicts fields via descriptors

🗝️ maproxylib — Mapping Proxy Library

Transparent access to nested objects/dicts fields via descriptors.

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maproxylib is a lightweight Python library that allows you to transparently access inner objects/dicts fields as class attributes, using the power of descriptors. Especially useful when working with JSON models, DTOs, complex nested structures, and API responses.

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✨ Features

• Simple dot-style access to dictionary values
• Support for deeply nested structures (via path)
• Type hint support (typing, TypeVar)
• Integration with dataclasses
• Read-only fields support

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🚀 Installation

Various dependency management tools are supported:

pip

pip install maproxylib

poetry

poetry add maproxylib

uv

uv add maproxylib

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💡 Usage Examples

1. Basic Usage

from dataclasses import dataclass, field

from maproxylib import ProxyFieldFactory

params_field = ProxyFieldFactory(storage_name="params")
# Descriptor factory for storage `params`

@dataclass
class MyModel:
    params: dict = field(default_factory=dict)
    # The storage for `params_field` descriptors

    name = params_field[str](default="Guest")
    age = params_field[int](default=30)

model = MyModel()
assert model.name == "Guest"  # Default value (storage is empty)

model.name = "Alice"  # Set values in storage
model.age = 25
assert model.params == {"name": "Alice", "age": 25}  # Actual values in storage

2. Nested Fields

from dataclasses import dataclass, field

from maproxylib import ProxyFieldFactory

data_field = ProxyFieldFactory(storage_name="data")
# Descriptor fabric for storage `data`

@dataclass
class User:
    data: dict = field(default_factory=dict)  # Storage
    city = data_field[str](key="address.city", default="Unknown")
    # The descriptor key in dot notation represents access to `data["address"]["city"]`

user = User()
user.city = "Moscow"  # Same as user.data["address"]["city"] = "Moscow"

assert user.data == {"address": {"city": "Moscow"}}
# The storage contains current values ​​in the required structure

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📦 Key Components

Component	Description
ProxyField[T]	A descriptor that provides access to a field
ProxyFieldFactory(...)	Factory for creating descriptors with preset parameters

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🧪 Testing

You can easily test with pytest:

uv sync --group dev
uv run pytest

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🛠️ Development

To install the package locally in development mode:

uv sync --group dev
uv install -e .

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🤝 Contributing

Any suggestions, feature requests, and PRs are welcome!
Feel free to open issues on GitHub 👉 issues

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⚖️ License

MIT License – see the LICENSE file for details.

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📬 Author

• @arnetkachev

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🔗 Links

• PyPI: https://pypi.org/project/maproxylib/
• GitHub: https://github.com/arnetkachev/maproxylib