foxbank/server/foxbank_server/decorators.py

import sys
from types import ModuleType
from flask import request
from http import HTTPStatus
from functools import wraps
from . import ram_db
from . import returns

_token: str | None = None
_user_id: int | None = None

class Module(ModuleType):
    def no_content(self, fn):
        """
        Allows a Flask route to return None, which is converted into
        HTTP 201 No Content.
        """
        @wraps(fn)
        def wrapper(*args, **kargs):
            result = fn(*args, **kargs)
            if result is None:
                return None, HTTPStatus.NO_CONTENT
            else:
                return result
        return wrapper

    @property
    def token(self) -> str:
        if _token is None:
            raise Exception('No token available')
        return _token

    @property
    def user_id(self) -> int:
        if _user_id is None:
            raise Exception('No user_id available')
        return _user_id

    def ensure_logged_in(self, fn):
        """
        Ensure the user is logged in by providing an Authorization: Bearer token
        header.

        @param token whether the token should be supplied after validation
        @param user_id whether the user_id should be supplied after validation
        @return decorator which supplies the requested parameters
        """
        @wraps(fn)
        def wrapper(*args, **kargs):
            token = request.headers.get('Authorization', None)
            if token is None:
                return returns.abort(returns.NO_AUTHORIZATION)
            if not token.startswith('Bearer '):
                return returns.abort(returns.INVALID_AUTHORIZATION)
            token = token[7:]
            user_id = ram_db.get_user(token)
            if user_id is None:
                return returns.abort(returns.INVALID_AUTHORIZATION)

            global _token
            _token = token
            global _user_id
            _user_id = user_id

            result = fn(*args, **kargs)

            _token = None
            _user_id = None

            return result

        return wrapper

sys.modules[__name__] = Module(__name__)