BlueprintSetupState Class — flask Architecture

Source Code

src/flask/sansio/blueprints.py lines 34–116

class BlueprintSetupState:
    """Temporary holder object for registering a blueprint with the
    application.  An instance of this class is created by the
    :meth:`~flask.Blueprint.make_setup_state` method and later passed
    to all register callback functions.
    """

    def __init__(
        self,
        blueprint: Blueprint,
        app: App,
        options: t.Any,
        first_registration: bool,
    ) -> None:
        #: a reference to the current application
        self.app = app

        #: a reference to the blueprint that created this setup state.
        self.blueprint = blueprint

        #: a dictionary with all options that were passed to the
        #: :meth:`~flask.Flask.register_blueprint` method.
        self.options = options

        #: as blueprints can be registered multiple times with the
        #: application and not everything wants to be registered
        #: multiple times on it, this attribute can be used to figure
        #: out if the blueprint was registered in the past already.
        self.first_registration = first_registration

        subdomain = self.options.get("subdomain")
        if subdomain is None:
            subdomain = self.blueprint.subdomain

        #: The subdomain that the blueprint should be active for, ``None``
        #: otherwise.
        self.subdomain = subdomain

        url_prefix = self.options.get("url_prefix")
        if url_prefix is None:
            url_prefix = self.blueprint.url_prefix
        #: The prefix that should be used for all URLs defined on the
        #: blueprint.
        self.url_prefix = url_prefix

        self.name = self.options.get("name", blueprint.name)
        self.name_prefix = self.options.get("name_prefix", "")

        #: A dictionary with URL defaults that is added to each and every
        #: URL that was defined with the blueprint.
        self.url_defaults = dict(self.blueprint.url_values_defaults)
        self.url_defaults.update(self.options.get("url_defaults", ()))

    def add_url_rule(
        self,
        rule: str,
        endpoint: str | None = None,
        view_func: ft.RouteCallable | None = None,
        **options: t.Any,
    ) -> None:
        """A helper method to register a rule (and optionally a view function)
        to the application.  The endpoint is automatically prefixed with the
        blueprint's name.
        """
        if self.url_prefix is not None:
            if rule:
                rule = "/".join((self.url_prefix.rstrip("/"), rule.lstrip("/")))
            else:
                rule = self.url_prefix
        options.setdefault("subdomain", self.subdomain)
        if endpoint is None:
            endpoint = _endpoint_from_view_func(view_func)  # type: ignore
        defaults = self.url_defaults
        if "defaults" in options:
            defaults = dict(defaults, **options.pop("defaults"))

        self.app.add_url_rule(
            rule,
            f"{self.name_prefix}.{self.name}.{endpoint}".lstrip("."),
            view_func,
            defaults=defaults,