.. _cbh-base-handler:

===========
BaseHandler
===========

Base handler is generic abstract class and should be used in all other class-based handlers.

Import: :code:`from aiogram.handlers import BaseHandler`

By default you will need to override only method :code:`async def handle(self) -> Any: ...`

This class also has a default initializer and you don't need to change it.
The initializer accepts the incoming event and all contextual data, which
can be accessed from the handler through attributes: :code:`event: TelegramEvent` and :code:`data: Dict[Any, str]`

If an instance of the bot is specified in context data or current context it can be accessed through *bot* class attribute.

Example
=======

.. code-block:: python

    class MyHandler(BaseHandler[Message]):
        async def handle(self) -> Any:
             await self.event.answer("Hello!")
