pico-fastapi 0.1.0

Pico-ioc integration for FastAPI. Adds Spring Boot-style controllers, autoconfiguration, and scopes (request, websocket, session).

📦 pico-fastapi

pico-fastapi integrates Pico-IoC with FastAPI, enabling constructor-based dependency injection, scoped lifecycles, and clean architectural boundaries — without global state or FastAPI dependency functions.

🐍 Requires Python 3.10+
✅ Fully async-compatible
✅ Real IoC (constructor injection, not function injection)
✅ Works with request, session, and websocket scopes

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🎯 Why pico-fastapi?

FastAPI’s built-in dependency system is function-based, which makes business logic tightly coupled to the framework.

pico-fastapi moves dependency resolution to the IoC container.

Concern	FastAPI Default	pico-fastapi
Dependency injection	Function-based	Constructor-based
Architecture	Framework-driven	Domain-driven
Testing	Must simulate DI functions	Component overrides at container init
Scopes	Manual or ad-hoc	singleton, request, session, websocket

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🧱 Core Features

• @controller class-based routing
• @get, @post, @websocket, etc.
• Constructor injection for controllers & services
• Automatic registration into FastAPI
• Scoped resolution via middleware (request, session, websocket)
• Full compatibility with Pico-IoC features: overrides, profiles, interceptors, cleanup

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📦 Installation

pip install pico-fastapi

Also requires:

pip install pico-ioc fastapi

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🚀 Quick Example

# controllers.py
from pico_fastapi import controller, get

@controller(prefix="/api")
class ApiController:
    def __init__(self, service: "MyService"):
        self.service = service

    @get("/hello")
    async def hello(self):
        return {"msg": self.service.greet()}

# services.py
class MyService:
    def greet(self) -> str:
        return "hello from service"

# main.py
from pico_ioc import init
from fastapi import FastAPI

container = init(
    modules=[
        "controllers",
        "services",
        "pico_fastapi.factory",
    ]
)

app = container.get(FastAPI)  # ✅ retrieve the fully configured app

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💬 WebSocket Example

from pico_fastapi import controller, websocket
from fastapi import WebSocket

@controller
class ChatController:
    async def __init__(self):
        pass

    @websocket("/ws")
    async def chat(self, websocket: WebSocket):
        await websocket.accept()
        while True:
            message = await websocket.receive_text()
            await websocket.send_text(f"Echo: {message}")

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🧪 Testing with Overrides

from pico_ioc import init
from fastapi import FastAPI
from fastapi.testclient import TestClient

class FakeService:
    def greet(self) -> str:
        return "test"

container = init(
    modules=["controllers", "services", "pico_fastapi.factory"],
    overrides={ "MyService": FakeService() }
)

app = container.get(FastAPI)
client = TestClient(app)

assert client.get("/api/hello").json() == {"msg": "test"}

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⚙️ How It Works

• @controller classes are registered automatically
• HTTP/WebSocket handlers are wrapped in a request or websocket scope
• All dependencies (services, config, state) are resolved through Pico-IoC
• Cleanup happens at application shutdown via lifespan integration

No global state. No implicit singletons. No magic.

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📝 License

MIT — See LICENSE.