kiwi-vpn/api/kiwi_vpn_api/routers/_common.py

"""
Common dependencies for routers.
"""

from fastapi import Depends, HTTPException, status
from fastapi.security import OAuth2PasswordBearer

from ..config import Config, Settings
from ..db import Device, User

oauth2_scheme = OAuth2PasswordBearer(
    tokenUrl=f"{Settings._.api_v1_prefix}/user/authenticate"
)


class Responses:
    """
    Just a namespace.

    Describes API response status codes.
    """

    OK = {
        "content": None,
    }
    INSTALLED = {
        "description": "kiwi-vpn already installed",
        "content": None,
    }
    NOT_INSTALLED = {
        "description": "kiwi-vpn not installed",
        "content": None,
    }
    NEEDS_USER = {
        "description": "Must be logged in",
        "content": None,
    }
    NEEDS_PERMISSION = {
        "description": "Operation not permitted",
        "content": None,
    }
    ENTRY_EXISTS = {
        "description": "Entry exists in database",
        "content": None,
    }
    ENTRY_DOESNT_EXIST = {
        "description": "Entry does not exist in database",
        "content": None,
    }


async def get_current_config(
    current_config: Config | None = Depends(Config.load),
) -> Config:
    """
    Get the current configuration if it exists.
    """

    # fail if not configured
    if current_config is None:
        raise HTTPException(status_code=status.HTTP_400_BAD_REQUEST)

    return current_config


async def get_current_user(
    token: str = Depends(oauth2_scheme),
    current_config: Config = Depends(get_current_config),
) -> User:
    """
    Get the currently logged-in user if it exists.
    """

    # don't use error 404 here - possible user enumeration

    # fail if not requested by a user
    if (username := await current_config.jwt.decode_token(token)) is None:
        raise HTTPException(status_code=status.HTTP_403_FORBIDDEN)

    if (user := User.get(username)) is None:
        raise HTTPException(status_code=status.HTTP_403_FORBIDDEN)

    return user


async def get_user_by_name(
    user_name: str,
    _: Config = Depends(get_current_config),
) -> User | None:
    """
    Get a user by name.
    """

    return User.get(user_name)


async def get_device_by_id(
    device_id: int,
    current_config: Config = Depends(get_current_config),
) -> Device | None:

    # can't connect to an unconfigured database
    if current_config is None:
        raise HTTPException(status_code=status.HTTP_400_BAD_REQUEST)

    # fail if device doesn't exist
    if (device := Device.get(device_id)) is None:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND)

    return device