How to use the router level dependency in the routes?

[abbazs]

Example Code

def get_db_connection():
    conn = pymssql.connect(
        server=settings.server,
        user=settings.user,
        password=settings.password,
        database=settings.database,
        port=settings.port,
        as_dict=True,
    )
    try:
        yield conn
    finally:
        conn.close()


router = APIRouter(
    prefix="/project",
    tags=["project"],
    dependencies=[Depends(get_db_connection)],
    responses={418: {"description": "Project status API."}},
)


@router.get("/count/{status}")
def projects_count(
    status: str, conn: pymssql.Connection = Depends(get_db_connection)
) -> dict:
    try:
        if status.upper() == "ALL":
            status = None
        return aq.get_project_count(conn, status=status)
    except:
        raise HTTPException(404, "Unable to get project count")

Description

There are several endpoints in the router. And all of them have the parameter conn. Can I avoid declaring this parameter at each router by declaring it as the dependency at APIRouter? And how to access the dependency declared at APIRouter in a route?

Operating System

Linux

Operating System Details

No response

FastAPI Version

0.66.0

Python Version

3.9.6

Additional Context

When I did google search for the same, the following is what I get:
#424
https://stackoverflow.com/questions/63961339/how-to-access-route-dependencies-in-custom-apiroute-class
https://stackoverflow.com/questions/64506036/fastapi-how-to-access-attributes-of-class-based-dependency-inside-route-when-dep

Is there a simpler solution?

[jiteshy]

The way you have specified dependencies in APIRouter as below is correct (Reference: Dependency in APIRouter ) :
dependencies=[Depends(get_db_connection)]

This can be taken even one more level up to declaring FastAPI app if it's needed for all the Routers (Reference: Dependency in FastAPI )
app = FastAPI(dependencies=[Depends(get_db_connection)])

With that, I think accessing the dependency as below should work considering you are specifying the dependency in the router (It worked for my sample code).

router.dependencies[0].dependency()

however I am not sure if there is a more elegant way to access the Router/App level dependencies in endpoints.

[ben519]

I also have this question. Additionally..

Is there any benefit to including dependencies=[Depends(get_db_connection)] within the declaration of APIRouter(), considering we need to include it as a parameter in every path operation function? Seems unnecessarily redundant.

[marcodelmoral]

Any ideas how to reduce redundancy in the declaration of router dependencies? I want to access my settings dependency, usually declared as a global dependency, inside my router endpoints.

[wesselvl1]

router = APIRouter(
    prefix="/il_oedometer/casagrande",
    tags=["/il_oedometer/casagrande"],
    dependencies=[Depends(deps.get_casagrande_service)],
)

logger = logging.getLogger(__name__)
casagrandeService = deps.get_casagrande_service()

I actually did it like this so the casagrandeService is callable in all functions. But came here to figure out if this was a good way to tackle this or not. (Probably not)