Method from_json

cmd2/history.py:351–372

Restore History from a JSON string. :param history_json: history data as JSON string (generated using to_json()) :return: History object :raises json.JSONDecodeError: if passed invalid JSON string :raises KeyError: if JSON is missing required elements :raises

(history_json: str)

    @staticmethod
    def from_json(history_json: str) -> "History":
        """Restore History from a JSON string.

        :param history_json: history data as JSON string (generated using to_json())
        :return: History object
        :raises json.JSONDecodeError: if passed invalid JSON string
        :raises KeyError: if JSON is missing required elements
        :raises ValueError: if history version in JSON isn't supported
        """
        json_dict = json.loads(history_json)
        version = json_dict[History._history_version_field]
        if version != History._history_version:
            raise ValueError(
                f"Unsupported history file version: {version}. This application uses version {History._history_version}."
            )

        items = json_dict[History._history_items_field]
        history = History()
        for hi_dict in items:
            history.append(HistoryItem.from_dict(hi_dict))

        return history