Method record_once

src/flask/sansio/blueprints.py:233–244

Works like :meth:`record` but wraps the function in another function that will ensure the function is only called once. If the blueprint is registered a second time on the application, the function passed is not called.

(self, func: DeferredSetupFunction)

    @setupmethod
    def record_once(self, func: DeferredSetupFunction) -> None:
        """Works like :meth:`record` but wraps the function in another
        function that will ensure the function is only called once.  If the
        blueprint is registered a second time on the application, the
        function passed is not called.
        """

        def wrapper(state: BlueprintSetupState) -> None:
            if state.first_registration:
                func(state)

        self.record(update_wrapper(wrapper, func))

    def make_setup_state(
        self, app: App, options: dict[str, t.Any], first_registration: bool = False