Dependency injection of crud items

[SarloAkrobata]

from typing import Any, List

from fastapi import APIRouter, Depends, HTTPException
from sqlalchemy.orm import Session

from app import crud, models, schemas
from app.api import deps

router = APIRouter()



@router.post("/", response_model=schemas.Item)
def create_item(
    *,
    db: Session = Depends(deps.get_db),
    item_in: schemas.ItemCreate,
    current_user: models.User = Depends(deps.get_current_active_user),
) -> Any:
    """
    Create new item.
    """
    item = crud.item.create_with_owner(db=db, obj_in=item_in, owner_id=current_user.id)
    return item

Hi all, why in this and similiar examples crud.item(or user) not injected as dependency?

[bereydev]

Hey @SarloAkrobata,

crud.item and crud.user or any other functions are not injected as dependencies because they are static functions or variables used directly in the code of the route. FastAPI’s dependency injection is meant for dynamic values like db or current_user that change per request.

Basically if your value depends (that's the keyword here 😉) on the request content and can change or has to be regenerated per request you can use a dependency. If your function, variable or constant is the same for any request then it does not make sens to be a dependency and can be used directly in the body of your route.

I invite your to take a second look at the documentation about dependencies:
https://fastapi.tiangolo.com/tutorial/dependencies/

Hope it helps!