FastAPI Request User Context

If your FastAPI app wants the resolved Main Sequence user attached to request.state, add the Main Sequence request-context middleware at app startup.

Use:

from fastapi import FastAPI, Request

from mainsequence.client.fastapi import LoggedUserContextMiddleware


app = FastAPI(
    title="My API",
    version="0.1.0",
)

app.add_middleware(LoggedUserContextMiddleware)


@app.get("/me")
def get_me(request: Request) -> dict[str, object]:
    user = request.state.user
    return {
        "id": request.state.user_id,
        "username": user.username,
        "email": user.email,
    }

What the middleware does:

• binds the current request headers into mainsequence.client.models_user._CURRENT_AUTH_HEADERS
• resolves the current user through User.get_logged_user()
• stores the resolved user on request.state.user
• stores the resolved user id on request.state.user_id

Use request.state.user inside route handlers when you already have the request object. That is the clearest path.

Use User.get_logged_user() when you are in shared helper code that does not receive the request object directly.

If you do not add the middleware, request.state.user is not populated automatically. It only means this request-local convenience layer is absent.

Use this pattern when you want request-local state:

app = FastAPI(...)
app.add_middleware(LoggedUserContextMiddleware)

That setup is useful when you want the resolved Main Sequence user available directly on request.state.