Starlette (and other ASGI frameworks)

There is no Starlette-specific integration in diwire (by design). The recommended pattern is:

1. Build a container at startup.

2. Use @resolver_context.inject(scope=Scope.REQUEST) for request handlers.

3. Use contextvars only for request-bound objects (Request, user, trace id, …), not for “current container”.

Minimal sketch

from contextvars import ContextVar

from starlette.applications import Starlette
from starlette.middleware import Middleware
from starlette.middleware.base import BaseHTTPMiddleware
from starlette.requests import Request
from starlette.responses import JSONResponse

from diwire import Container, Injected, Scope, resolver_context

request_var: ContextVar[Request] = ContextVar("request_var")


class RequestVarMiddleware(BaseHTTPMiddleware):
    async def dispatch(self, request: Request, call_next):
        token = request_var.set(request)
        try:
            return await call_next(request)
        finally:
            request_var.reset(token)


app = Starlette(middleware=[Middleware(RequestVarMiddleware)])
container = Container()

container.add_factory(
    lambda: request_var.get(),
    provides=Request,
    scope=Scope.REQUEST,
)


class Service:
    ...


container.add(Service, provides=Service, scope=Scope.REQUEST)


@resolver_context.inject(scope=Scope.REQUEST)
async def handler(request: Request, service: Injected[Service]) -> JSONResponse:
    _ = request
    _ = service
    return JSONResponse({"ok": True})

The exact routing API differs between ASGI frameworks, but the DI pieces stay the same.