Modern-DI integration for Starlette.

Installation

uv add modern-di-starlette      # or: pip install modern-di-starlette

Usage

setup_di registers the container, composes the lifespan, and installs middleware that builds a per-connection child container. Decorate an endpoint with @inject and mark parameters with FromDI to receive resolved dependencies. Starlette has no native DI, so @inject is required (there is no Depends).

import dataclasses
import typing

from modern_di import Container, Group, Scope, providers
from modern_di_starlette import FromDI, inject, setup_di
from starlette.applications import Starlette
from starlette.requests import Request
from starlette.responses import JSONResponse
from starlette.routing import Route


@dataclasses.dataclass(kw_only=True)
class Settings:
    debug: bool = True


@dataclasses.dataclass(kw_only=True)
class UserService:
    settings: Settings  # auto-injected by type


class Dependencies(Group):
    settings = providers.Factory(scope=Scope.APP, creator=Settings)
    user_service = providers.Factory(scope=Scope.REQUEST, creator=UserService)


@inject
async def homepage(
    request: Request,
    service: typing.Annotated[UserService, FromDI(Dependencies.user_service)],
) -> JSONResponse:
    return JSONResponse({"debug": service.settings.debug})


app = Starlette(routes=[Route("/", homepage)])
container = Container(groups=[Dependencies], validate=True)
setup_di(app, container)

Part of modern-python

Built on modern-di. See the docs for all integrations.