python - 使用方法自动验证函数参数

Question

有什么方法可以在 Python 3 中将装饰器附加到以下函数，从而避免调用 _is_valid_token()？我会将这个静态值作为 key 传递给每个函数，以通过 SSL 调用 API 并希望简化我的代码。

# Constants
TOKEN = '7632ba6a-0609-4b0c-a92e-9107bec88941'


@app.route('/my-game-server/api/v1.0/create_new_game/<token>/<player1>/<player2>/<rules>',
           methods=['GET'])
def create_new_game(token, player1, player2, rules):
    # Create
    """Creates a new game from scratch

    :param token: Unique value that verifies the caller is valid
    :param player1: Name of the first player
    :param player2: Name of the second player
    :param rules: String representing the rules to be used in the game
    :return: UUID representing the game id that has been created
    """
    # Validate token
    _is_valid_token(token)

    # Create game
    game_id = str(uuid.uuid4())

    return game_id


def _is_valid_token(token):
    """Validate that the caller has a legitimate call into the service

    :param token: Unique value that verifies the caller is valid
    """
    if token != TOKEN:
        abort(400)

Answer 1

您可以使用 url processor .

@app.url_value_preprocessor
def _is_valid_token(endpoint, values):
    if 'token' not in values:
        return

    if values['token'] != TOKEN:
        abort(400)

这适用于所有路由，但仅在路由实际具有“ token ​​”值时才进行验证。当然，您可以事先进行许多其他检查来限制验证，例如将其基于特定端点名称，但这是最通用的功能。

---

您也可以只装饰要验证的特定功能。这比 Flask 解决方案更通用。

def _is_valid_token(f):
    @wraps(f)
    def decorated(token, *args, **kwargs):
        if token != TOKEN:
            abort(400)

        return f(token, *args, **kwargs):

    return decorated

@app.route(...)
@_is_valid_token
def create_new_game(token, ...):
    ...