pynest-api 0.0.3

PyNest is a FastAPI Abstraction for building microservices, influenced by NestJS.

PyNest is a Python framework built on top of FastAPI that follows the modular architecture of NestJS

PyNest - Description

PyNest is designed to help structure your APIs in an intuitive, easy to understand, and enjoyable way.

With PyNest, you can build scalable and maintainable APIs with ease. The framework supports dependency injection, type annotations, decorators, and code generation, making it easy to write clean and testable code.

This framework is not a direct port of NestJS to Python but rather a re-imagining of the framework specifically for Python developers, including data scientists, data analysts, and data engineers. It aims to assist them in building better and faster APIs for their data applications.

Getting Started

To get started with PyNest, you'll need to install it using pip:

pip install pynest-api

Start with cli

pynest create-nest-app -n my_app_name

this command will create a new project with the following structure:

├── app.py
├── orm_config.py
├── main.py
├── src
│    ├── __init__.py
│    ├── examples
│    │    ├── __init__.py
│    │    ├── examples_controller.py
│    │    ├── examples_service.py
│    │    ├── examples_model.py
│    ├──  ├── examples_entity.py
│    ├──  ├── examples_module.py

once you have created your app, get into the folder and run the following command:

cd my_app_name

run the server with the following command:

uvicorn "app:app" --host "0.0.0.0" --port "80" --reload

Now you can visit OpenAPI in your browser to see the default API documentation.

Adding modules

To add a new module to your application, you can use the pynest generate module command:

pynest generate-module -n users

This will create a new module called users in your application with the following structure:

├── users
│    ├── __init__.py
│    ├── users_controller.py
│    ├── users_service.py
│    ├── users_model.py
│    ├── users_entity.py
│    ├── users_module.py

The users module will immediately register itself with the application and will be available for use.

You can then start defining routes and other application components using decorators and other PyNest constructs.

For more information on how to use PyNest, check out the official documentation at https://pythonnest.github.io/PyNest/.

Starting a new project manually

NOTICE: for the following example, we will use the products module. 

To start a new project manually, you'll need to create a project that follows this structure:

├── app.py
├── orm_config.py
├── main.py
├── src
│    ├── __init__.py
│    ├── products
│    │    ├── __init__.py
│    │    ├── products_controller.py
│    │    ├── products_service.py
│    │    ├── products_model.py
│    ├──  ├── products_entity.py
│    ├──  ├── products_module.py

Explanation: This is the directory structure for your project. It includes the main files and a src directory that contains your project's source code.

Creating the files

main.py

import uvicorn


if __name__ == '__main__':
    uvicorn.run(
        'app:app',
        host="0.0.0.0",
        port=80,
    )

This is the main.py file, which is responsible for running your application using the Uvicorn server.
It imports the uvicorn library and starts the server with the specified host and port.

app.py

from orm_config import config
from nest.core import App
from src.products.products_module import ProductsModule

app = App(
    description="Your app description",
    modules=[
        ProductsModule
    ],
    init_db=config.create_all
)

This is the app.py file, which is the entry point for your application. It imports necessary modules and sets up the App object with a description and the ProductsModule.
It also initializes the database using the config.create_all function.

orm_config.py

from nest.core import OrmService
import os
from dotenv import load_dotenv

load_dotenv()

config = OrmService(
    db_type="your_db_type",
    config_params=dict(
        user=os.getenv("DB_USER"),
        password=os.getenv("DB_PASSWORD"),
        host=os.getenv("DB_HOST"),
        port=os.getenv("DB_PORT"),
        database=os.getenv("DB_NAME"),
    ),
)

This is the orm_config.py file, which contains the configuration for your ORM (Object-Relational Mapping) service.

It imports necessary libraries, loads environment variables using dotenv, and creates an OrmService object with the specified database type and configuration parameters.

---

Once we set up this 3 files, we can start creating our modules. each module is a folder with the following structure:

├── products
│    ├── __init__.py
│    ├── products_controller.py
│    ├── products_service.py
│    ├── products_model.py
|    ├── products_entity.py
│    ├── products_module.py

This is the structure of a module folder. It includes an init.py file to make the folder a Python package,
As well as specific files for the module's controller, service, model, entity, and module configurations.

products_model.py

from pydantic import BaseModel


class Product(BaseModel):
    name: str
    price: float
    description: str

This is the products_model.py file, which defines the Product model using the BaseModel class from the pydantic library.
The model represents the structure and attributes of a product.

products_entity.py

from sqlalchemy import Column, Integer, String, Float
from orm_config import config


class Product(config.Base):
    __tablename__ = "products"

    id = Column(Integer, primary_key=True, index=True, autoincrement=True)
    name = Column(String)
    price = Column(Float)
    description = Column(String)

This is the products_entity.py file, which defines the Product entity using SQLAlchemy.
It imports necessary modules and inherits from the config.Base class. The entity represents the database table for storing products, with columns for id, name, price, and description.

products_service.py

from src.products.products_model import Product
from src.products.products_entity import Product as ProductEntity
from orm_config import config
from nest.core.decorators import db_request_handler


class ProductsService:
    def __init__(self):
        self.config = config
        self.session = self.config.get_db()

    @db_request_handler
    def add_product(self, product: Product):
        product_entity = ProductEntity(
            name=product.name,
            price=product.price,
            description=product.description
        )
        self.session.add(product_entity)
        self.session.commit()
        return product_entity.id

    @db_request_handler
    def get_products(self):
        return self.session.query(ProductEntity).all()

    @db_request_handler
    def get_product(self, product_id: int):
        return self.session.query(ProductEntity).filter(ProductEntity.id == product_id).first()

    @db_request_handler
    def last_product(self):
        return self.session.query(ProductEntity).order_by(ProductEntity.id.desc()).first()

This is the service file, which contains the ProductsService class. It imports necessary modules and defines methods for interacting with the database.
The methods include adding a product, getting all products, getting a specific product by ID, and retrieving the last added product.
The @db_request_handler decorator is responsible for managing the database session and handling any exceptions that may occur during database operations.

products_controller.py

from nest.core import Depends, Controller, Get, Post
from src.products.products_service import ProductsService
from src.products.products_model import Product


@Controller("products")
class ProductsController:
    service: ProductsService = Depends(ProductsService)

    @Get("/get_products")
    def get_products(self):
        return self.service.get_products()

    @Get("/get_product/{product_id}")
    def get_product(self, product_id: int):
        return self.service.get_product(product_id)

    @Post("/add_product")
    def add_product(self, product: Product):
        return self.service.add_product(product)

    @Get("/last_product")
    def last_product(self):
        return self.service.last_product()

In summary, the decorators and the Depends class are used to define routes and HTTP methods for the
ProductsController class, and to inject the ProductsService dependency into the service attribute of the controller.
This allows the controller to handle incoming requests and interact with
The service to perform specific actions based on the routes and methods defined.

products_module.py

from src.products.products_controller import ProductsController
from src.products.products_service import ProductsService


class ProductsModule:

    def __init__(self):
        self.providers = [ProductsService]
        self.controllers = [ProductsController]

This module can be registered and used in your application. Once the module is registered, the controller routes will be available at the specified path.

This 5 components are the minimum required to create a module that works with the ORM. There are many more options of how you can design your modules and which databases you can use, but this is the default basic structure.

Key Features

Modular Architecture

PyNest follows the modular architecture of NestJS, which allows for easy separation of concerns and code organization. Each module contains a collection of related controllers, services, and providers.

Dependency Injection

PyNest supports dependency injection, which makes it easy to manage dependencies and write testable code. You can easily inject services and providers into your controllers using decorators.

Decorators

PyNest makes extensive use of decorators to define routes, middleware, and other application components. This helps keep the code concise and easy to read.

Type Annotations

PyNest leverages Python's type annotations to provide better tooling and help prevent errors. You can annotate your controllers, services, and providers with types to make your code more robust.

Code Generation

PyNest includes a code generation tool that can create boilerplate code for modules, controllers, and other components. This saves you time and helps you focus on writing the code that matters.

Future Plans

• Create Marketplace for modules where developers can share their modules and download modules created by others.
• Crete Abstraction class to Modules and Services to allow for easy creation of modules and services.
• Add inheritance between controllers for creating more complex controllers.
• Add support for other databases (mongoDB, redis, etc.)
• Create out-of-the-box authentication module that can be easily integrated into any application.
• Add support for other testing frameworks and create testing templates.
• Add support for other web frameworks (Flask, Django, etc.) - Same Architecture, different engine.

Contributing

Contributions are welcome! Please feel free to grab one of the open issues, or open a new one if you have an idea for a new feature or improvement.

This would bring a huge impact to the project and the community.

License

PyNest is MIT licensed.

Credits

PyNest is inspired by NestJS.