ScriptInfo Class — flask Architecture

Source Code

src/flask/cli.py lines 293–372

class ScriptInfo:
    """Helper object to deal with Flask applications.  This is usually not
    necessary to interface with as it's used internally in the dispatching
    to click.  In future versions of Flask this object will most likely play
    a bigger role.  Typically it's created automatically by the
    :class:`FlaskGroup` but you can also manually create it and pass it
    onwards as click object.

    .. versionchanged:: 3.1
        Added the ``load_dotenv_defaults`` parameter and attribute.
    """

    def __init__(
        self,
        app_import_path: str | None = None,
        create_app: t.Callable[..., Flask] | None = None,
        set_debug_flag: bool = True,
        load_dotenv_defaults: bool = True,
    ) -> None:
        #: Optionally the import path for the Flask application.
        self.app_import_path = app_import_path
        #: Optionally a function that is passed the script info to create
        #: the instance of the application.
        self.create_app = create_app
        #: A dictionary with arbitrary data that can be associated with
        #: this script info.
        self.data: dict[t.Any, t.Any] = {}
        self.set_debug_flag = set_debug_flag

        self.load_dotenv_defaults = get_load_dotenv(load_dotenv_defaults)
        """Whether default ``.flaskenv`` and ``.env`` files should be loaded.

        ``ScriptInfo`` doesn't load anything, this is for reference when doing
        the load elsewhere during processing.

        .. versionadded:: 3.1
        """

        self._loaded_app: Flask | None = None

    def load_app(self) -> Flask:
        """Loads the Flask app (if not yet loaded) and returns it.  Calling
        this multiple times will just result in the already loaded app to
        be returned.
        """
        if self._loaded_app is not None:
            return self._loaded_app
        app: Flask | None = None
        if self.create_app is not None:
            app = self.create_app()
        else:
            if self.app_import_path:
                path, name = (
                    re.split(r":(?![\\/])", self.app_import_path, maxsplit=1) + [None]
                )[:2]
                import_name = prepare_import(path)
                app = locate_app(import_name, name)
            else:
                for path in ("wsgi.py", "app.py"):
                    import_name = prepare_import(path)
                    app = locate_app(import_name, None, raise_if_not_found=False)

                    if app is not None:
                        break

        if app is None:
            raise NoAppException(
                "Could not locate a Flask application. Use the"
                " 'flask --app' option, 'FLASK_APP' environment"
                " variable, or a 'wsgi.py' or 'app.py' file in the"
                " current directory."
            )

        if self.set_debug_flag:
            # Update the app's debug flag through the descriptor so that
            # other values repopulate as well.
            app.debug = get_debug_flag()

        self._loaded_app = app
        return app