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 Capability, 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_ADMIN = {
        "description": "Must be admin",
        "content": None,
    }
    NEEDS_ADMIN_OR_SELF = {
        "description": "Must be the requested user",
        "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_user(
    token: str = Depends(oauth2_scheme),
    current_config: Config | None = Depends(Config.load),
) -> User | None:
    """
    Get the currently logged-in user from the database.
    """

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

    username = await current_config.jwt.decode_token(token)

    return User.get(username)


async def get_current_user_if_exists(
    current_user: User | None = Depends(get_current_user),
) -> User:
    """
    Get the currently logged-in user if it exists.
    """

    # fail if not requested by a user
    if current_user is None:
        raise HTTPException(status_code=status.HTTP_403_FORBIDDEN)

    return current_user


async def get_current_user_if_admin(
    current_user: User = Depends(get_current_user_if_exists),
) -> User:
    """
    Get the currently logged-in user if it is an admin.
    """

    # fail if not requested by an admin
    if not current_user.can(Capability.admin):
        raise HTTPException(status_code=status.HTTP_403_FORBIDDEN)

    return current_user


async def get_current_user_if_admin_or_self(
    user_name: str,
    current_user: User = Depends(get_current_user_if_exists),
) -> User:
    """
    Get the currently logged-in user.

    Fails a) if the currently logged-in user is not the requested user,
    and b) if it is not an admin.
    """

    # fail if not requested by an admin or self
    if not (current_user.can(Capability.admin)
            or current_user.name == user_name):
        raise HTTPException(status_code=status.HTTP_403_FORBIDDEN)

    return current_user