App class
=========
.. _app-class:
The :class:`~micropie.App` class is the core of a MicroPie application.
It implements the ASGI call interface and dispatches HTTP, WebSocket
and lifespan events to your handlers. Subclass :class:`~micropie.App`
and add public methods to create route handlers. Instantiate your
subclass and pass the resulting object to an ASGI server such as
Uvicorn.
Constructor
-----------
.. class:: App(session_backend=None)
Create a new application. If *session_backend* is provided it must
be an instance of :class:`~micropie.SessionBackend`. When omitted,
MicroPie uses an in‑memory back‑end.
Attributes
----------
.. attribute:: middlewares
A list of :class:`~micropie.HttpMiddleware` instances. Middlewares
run before and after every HTTP request. Append a middleware
instance to enable it. See :doc:`../howto/middleware` for examples.
.. attribute:: ws_middlewares
A list of :class:`~micropie.WebSocketMiddleware` instances used for
WebSocket connections.
.. attribute:: session_backend
The active :class:`~micropie.SessionBackend` instance used to load
and save session dictionaries for both HTTP and WebSocket flows.
.. attribute:: startup_handlers
A list of asynchronous callables that run during the ASGI
``lifespan.startup`` event. Use this to set up resources such as
database connections. See :doc:`../tutorial/quickstart` for an
example.
.. attribute:: shutdown_handlers
A list of asynchronous callables that run during the ASGI
``lifespan.shutdown`` event. Use this to clean up resources.
Methods
-------
.. method:: __call__(scope, receive, send)
The ASGI entry point. Dispatches to HTTP, WebSocket or lifespan
handlers based on ``scope['type']``. You normally do not call this
directly; the ASGI server calls it for you.
.. attribute:: request
The current :class:`~micropie.Request` (or
:class:`~micropie.WebSocketRequest`) stored in a context variable for
the active request lifecycle.
.. method:: _redirect(location, extra_headers=None)
Return a tuple ``(302, '', headers)`` representing an HTTP redirect
to *location*. Use this helper in your handlers to redirect the
client.
.. method:: _render_template(name, **kwargs)
Render a Jinja2 template asynchronously. Returns a string
containing the rendered output. Requires Jinja2 to be installed.
See :doc:`../howto/templates` for details.
Additionally, MicroPie defines several private helper methods such as
``_parse_cookies`` and ``_send_response``. These are considered
internal and not part of the public API. They may change without
notice.
