init() — flask Function Reference

Architecture documentation for the __init__() function in app.py from the flask codebase.

Function python ApplicationCore Scaffolding calls 3

Entity Profile

ApplicationCore→ Scaffolding→ __init__() — flask Function Reference

Dependency Diagram

graph TD
  4b05301c_76b4_7bf6_5a71_e4588c1d623f["__init__()"]
  38f6d4a2_834e_2acd_e1b6_f45c58079ccd["App"]
  4b05301c_76b4_7bf6_5a71_e4588c1d623f -->|defined in| 38f6d4a2_834e_2acd_e1b6_f45c58079ccd
  5d914b38_d2af_c173_db31_3a2d1e8e567d["auto_find_instance_path()"]
  4b05301c_76b4_7bf6_5a71_e4588c1d623f -->|calls| 5d914b38_d2af_c173_db31_3a2d1e8e567d
  908b035e_2774_0f2e_e247_003a3044450d["make_config()"]
  4b05301c_76b4_7bf6_5a71_e4588c1d623f -->|calls| 908b035e_2774_0f2e_e247_003a3044450d
  ddf03535_deb9_49d0_f14d_3127a2c7daaa["make_aborter()"]
  4b05301c_76b4_7bf6_5a71_e4588c1d623f -->|calls| ddf03535_deb9_49d0_f14d_3127a2c7daaa
  style 4b05301c_76b4_7bf6_5a71_e4588c1d623f fill:#6366f1,stroke:#818cf8,color:#fff

Relationship Graph

Source Code

src/flask/sansio/app.py lines 279–408

    def __init__(
        self,
        import_name: str,
        static_url_path: str | None = None,
        static_folder: str | os.PathLike[str] | None = "static",
        static_host: str | None = None,
        host_matching: bool = False,
        subdomain_matching: bool = False,
        template_folder: str | os.PathLike[str] | None = "templates",
        instance_path: str | None = None,
        instance_relative_config: bool = False,
        root_path: str | None = None,
    ) -> None:
        super().__init__(
            import_name=import_name,
            static_folder=static_folder,
            static_url_path=static_url_path,
            template_folder=template_folder,
            root_path=root_path,
        )

        if instance_path is None:
            instance_path = self.auto_find_instance_path()
        elif not os.path.isabs(instance_path):
            raise ValueError(
                "If an instance path is provided it must be absolute."
                " A relative path was given instead."
            )

        #: Holds the path to the instance folder.
        #:
        #: .. versionadded:: 0.8
        self.instance_path = instance_path

        #: The configuration dictionary as :class:`Config`.  This behaves
        #: exactly like a regular dictionary but supports additional methods
        #: to load a config from files.
        self.config = self.make_config(instance_relative_config)

        #: An instance of :attr:`aborter_class` created by
        #: :meth:`make_aborter`. This is called by :func:`flask.abort`
        #: to raise HTTP errors, and can be called directly as well.
        #:
        #: .. versionadded:: 2.2
        #:     Moved from ``flask.abort``, which calls this object.
        self.aborter = self.make_aborter()

        self.json: JSONProvider = self.json_provider_class(self)
        """Provides access to JSON methods. Functions in ``flask.json``
        will call methods on this provider when the application context
        is active. Used for handling JSON requests and responses.

        An instance of :attr:`json_provider_class`. Can be customized by
        changing that attribute on a subclass, or by assigning to this
        attribute afterwards.

        The default, :class:`~flask.json.provider.DefaultJSONProvider`,
        uses Python's built-in :mod:`json` library. A different provider
        can use a different JSON library.

        .. versionadded:: 2.2
        """

        #: A list of functions that are called by
        #: :meth:`handle_url_build_error` when :meth:`.url_for` raises a
        #: :exc:`~werkzeug.routing.BuildError`. Each function is called
        #: with ``error``, ``endpoint`` and ``values``. If a function
        #: returns ``None`` or raises a ``BuildError``, it is skipped.
        #: Otherwise, its return value is returned by ``url_for``.
        #:
        #: .. versionadded:: 0.9
        self.url_build_error_handlers: list[
            t.Callable[[Exception, str, dict[str, t.Any]], str]
        ] = []

        #: A list of functions that are called when the application context
        #: is destroyed.  Since the application context is also torn down
        #: if the request ends this is the place to store code that disconnects
        #: from databases.
        #:
        #: .. versionadded:: 0.9