How to list additional possible error HTTP codes for endpoint?

I am using the fastAPI to build API.

It allows to generate API docs automatically.

It also shows list of possible response codes. By default it shows only a success code and 422 code.

But in my app there are more codes allowed. For example 404, 401, 403 etc. All these exceptions are not inside a code of en endpoint. It is inside a package

@app.get("/items/{item_id}")
async def read_item(item_id: str):
    data, error, message = do_something()
    if error != 0:
        raise HTTPException(status_code=error, detail=message)
    return data

How can i notify the decorator about all possible codes? is it possible?

You can use APIRouter in fastapi to define routes and customized responses:

from fastapi import HTTPException, APIRouter

router = APIRouter()

@router.get("/items/{item_id}")
async def read_item(item_id: str):
    data, error, message = do_something()
    if error != 0:
        raise HTTPException(status_code=error, detail=message)
    return data

then you can define your desired responses:

read_item.responses = {
    200: {"description": "Successful response"},
    404: {"description": "Item not found"},
    401: {"description": "Unauthorized access"},
    403: {"description": "Forbidden access"}
}

Another approach is to define response in @router.get():

@router.get("/items/{item_id}",
    description="Retrieves an item by its ID.",
    response_model=Item,
    responses={
        200: {"description": "Successful response"},
        404: {"description": "Item not found"},
        401: {"description": "Unauthorized access"},
        403: {"description": "Forbidden access"}
    }
)