Typed data (#1647)

* Add TypedDict support for middleware context data

Introduced `MiddlewareData` and associated TypedDicts to type-hint middleware context data. Updated documentation to include usage examples and guidelines for extending the default middleware data. Also adjusted coverage configuration to exclude the new data module.

* Added more docstrings

* Typo fixes

aiogram/dispatcher/middlewares/data.py

@@ -0,0 +1,97 @@
+from __future__ import annotations
+
+from typing import TYPE_CHECKING, TypedDict
+
+from typing_extensions import NotRequired
+
+if TYPE_CHECKING:
+    from aiogram import Bot, Dispatcher, Router
+    from aiogram.dispatcher.event.handler import HandlerObject
+    from aiogram.dispatcher.middlewares.user_context import EventContext
+    from aiogram.fsm.context import FSMContext
+    from aiogram.fsm.storage.base import BaseStorage
+    from aiogram.types import Chat, Update, User
+    from aiogram.utils.i18n import I18n, I18nMiddleware
+
+
+class DispatcherData(TypedDict, total=False):
+    """
+    Dispatcher and bot related data.
+    """
+
+    dispatcher: Dispatcher
+    """Instance of the Dispatcher from which the handler was called."""
+    bot: Bot
+    """Bot that received the update."""
+    bots: NotRequired[list[Bot]]
+    """List of all bots in the Dispatcher. Used only in polling mode."""
+    event_update: Update
+    """Update object that triggered the handler."""
+    event_router: Router
+    """Router that was used to find the handler."""
+    handler: NotRequired[HandlerObject]
+    """Handler object that was called.
+    Available only in the handler itself and inner middlewares."""
+
+
+class UserContextData(TypedDict, total=False):
+    """
+    Event context related data about user and chat.
+    """
+
+    event_context: EventContext
+    """Event context object that contains user and chat data."""
+    event_from_user: NotRequired[User]
+    """User object that triggered the handler."""
+    event_chat: NotRequired[Chat]
+    """Chat object that triggered the handler.
+    .. deprecated:: 3.5.0
+        Use :attr:`event_context.chat` instead."""
+    event_thread_id: NotRequired[int]
+    """Thread ID of the chat that triggered the handler.
+    .. deprecated:: 3.5.0
+        Use :attr:`event_context.chat` instead."""
+    event_business_connection_id: NotRequired[str]
+    """Business connection ID of the chat that triggered the handler.
+    .. deprecated:: 3.5.0
+        Use :attr:`event_context.business_connection_id` instead."""
+
+
+class FSMData(TypedDict, total=False):
+    """
+    FSM related data.
+    """
+
+    fsm_storage: BaseStorage
+    """Storage used for FSM."""
+    state: NotRequired[FSMContext]
+    """Current state of the FSM."""
+    raw_state: NotRequired[str | None]
+    """Raw state of the FSM."""
+
+
+class I18nData(TypedDict, total=False):
+    """
+    I18n related data.
+
+    Is not included by default, you need to add it to your own Data class if you need it.
+    """
+
+    i18n: I18n
+    """I18n object."""
+    i18n_middleware: I18nMiddleware
+    """I18n middleware."""
+
+
+class MiddlewareData(
+    DispatcherData,
+    UserContextData,
+    FSMData,
+    # I18nData, # Disabled by default, add it if you need it to your own Data class.
+    total=False,
+):
+    """
+    Data passed to the handler by the middlewares.
+
+    You can add your own data by extending this class.
+    """