Inject in Routes

Use Injected[T] in FastAPI HTTP and WebSocket handlers.

HTTP Route Injection

from typing import Annotated
from fastapi import Header
from wireup import Inject, Injected


@app.get("/users")
async def users(
    # Inject services
    service: Injected[UserService],
    # Inject config values
    is_debug: Annotated[bool, Inject(config="debug")],
    # Regular FastAPI dependencies still work
    user_agent: Annotated[str | None, Header()] = None,
): ...

WebSocket Route Injection

from fastapi import WebSocket
from wireup import Injected


@app.websocket("/ws")
async def ws(
    websocket: WebSocket,
    greeter: Injected[GreeterService],
): ...

For injecting fastapi.Request and fastapi.WebSocket into scoped services, see Request and WebSocket Context in Services.

Improve Injection Performance

Use WireupRoute as the route_class for your FastAPI routers to improve injection performance.

from wireup.integration.fastapi import WireupRoute

router = fastapi.APIRouter(route_class=WireupRoute)

By default, FastAPI inspects every route parameter and will try to resolve even those meant only for Wireup. WireupRoute hides Wireup-specific parameter names (Injected[...], Annotated[..., Inject(...)]) from FastAPI, avoiding duplicated processing.

It is an optional optimization and not required for injection to work, but recommended for better performance. Set it on every router individually that uses Wireup injection.