Move update type detecting from Dispatcher to Update (#669)

* move update type detecting to Update

* requested changes

* fix typo

* requested changes

* add docstring

* Update CHANGES/669.misc

Co-authored-by: Alex Root Junior <jroot.junior@gmail.com>

* move mypy hack to utils, add lru_cache configuration

* More accurate description of the exception, thanks @uwinx

* Update CHANGES/669.misc

Co-authored-by: evgfilim1 <evgfilim1@yandex.ru>

* Callable import fix

Co-authored-by: evgfilim1 <evgfilim1@yandex.ru>

Co-authored-by: Alex Root Junior <jroot.junior@gmail.com>
Co-authored-by: evgfilim1 <evgfilim1@yandex.ru>

CHANGES/669.misc

@@ -0,0 +1 @@
+Moved update type detection from Dispatcher to Update object

aiogram/dispatcher/dispatcher.py

@@ -9,7 +9,8 @@ from typing import Any, AsyncGenerator, Dict, List, Optional, Union
 from .. import loggers
 from ..client.bot import Bot
 from ..methods import GetUpdates, TelegramMethod
-from ..types import TelegramObject, Update, User
+from ..types import Update, User
+from ..types.update import UpdateTypeLookupError
 from ..utils.backoff import Backoff, BackoffConfig
 from ..utils.exceptions.base import TelegramAPIError
 from ..utils.exceptions.network import NetworkError
@@ -186,47 +187,10 @@ class Dispatcher(Router):
         :param kwargs:
         :return:
         """
-        event: TelegramObject
-        if update.message:
-            update_type = "message"
-            event = update.message
-        elif update.edited_message:
-            update_type = "edited_message"
-            event = update.edited_message
-        elif update.channel_post:
-            update_type = "channel_post"
-            event = update.channel_post
-        elif update.edited_channel_post:
-            update_type = "edited_channel_post"
-            event = update.edited_channel_post
-        elif update.inline_query:
-            update_type = "inline_query"
-            event = update.inline_query
-        elif update.chosen_inline_result:
-            update_type = "chosen_inline_result"
-            event = update.chosen_inline_result
-        elif update.callback_query:
-            update_type = "callback_query"
-            event = update.callback_query
-        elif update.shipping_query:
-            update_type = "shipping_query"
-            event = update.shipping_query
-        elif update.pre_checkout_query:
-            update_type = "pre_checkout_query"
-            event = update.pre_checkout_query
-        elif update.poll:
-            update_type = "poll"
-            event = update.poll
-        elif update.poll_answer:
-            update_type = "poll_answer"
-            event = update.poll_answer
-        elif update.my_chat_member:
-            update_type = "my_chat_member"
-            event = update.my_chat_member
-        elif update.chat_member:
-            update_type = "chat_member"
-            event = update.chat_member
-        else:
+        try:
+            update_type = update.event_type
+            event = update.event
+        except UpdateTypeLookupError:
             warnings.warn(
                 "Detected unknown update type.\n"
                 "Seems like Telegram Bot API was updated and you have "

aiogram/types/update.py

@@ -1,7 +1,8 @@
 from __future__ import annotations
 
-from typing import TYPE_CHECKING, Optional
+from typing import TYPE_CHECKING, Optional, cast
 
+from ..utils.mypy_hacks import lru_cache
 from .base import TelegramObject
 
 if TYPE_CHECKING:  # pragma: no cover
@@ -53,3 +54,52 @@ class Update(TelegramObject):
     """*Optional*. The bot's chat member status was updated in a chat. For private chats, this update is received only when the bot is blocked or unblocked by the user."""
     chat_member: Optional[ChatMemberUpdated] = None
     """*Optional*. A chat member's status was updated in a chat. The bot must be an administrator in the chat and must explicitly specify 'chat_member' in the list of *allowed_updates* to receive these updates."""
+
+    def __hash__(self) -> int:
+        return hash((type(self), self.update_id))
+
+    @property  # type: ignore
+    @lru_cache()
+    def event_type(self) -> str:
+        """
+        Detect update type
+        If update type is unknown, raise UpdateTypeLookupError
+
+        :return:
+        """
+        if self.message:
+            return "message"
+        if self.edited_message:
+            return "edited_message"
+        if self.channel_post:
+            return "channel_post"
+        if self.edited_channel_post:
+            return "edited_channel_post"
+        if self.inline_query:
+            return "inline_query"
+        if self.chosen_inline_result:
+            return "chosen_inline_result"
+        if self.callback_query:
+            return "callback_query"
+        if self.shipping_query:
+            return "shipping_query"
+        if self.pre_checkout_query:
+            return "pre_checkout_query"
+        if self.poll:
+            return "poll"
+        if self.poll_answer:
+            return "poll_answer"
+        if self.my_chat_member:
+            return "my_chat_member"
+        if self.chat_member:
+            return "chat_member"
+
+        raise UpdateTypeLookupError("Update does not contain any known event type.")
+
+    @property
+    def event(self) -> TelegramObject:
+        return cast(TelegramObject, getattr(self, self.event_type))
+
+
+class UpdateTypeLookupError(LookupError):
+    """Update does not contain any known event type."""

aiogram/utils/mypy_hacks.py

@@ -0,0 +1,16 @@
+import functools
+from typing import Callable, TypeVar
+
+T = TypeVar("T")
+
+
+def lru_cache(maxsize: int = 128, typed: bool = False) -> Callable[[T], T]:
+    """
+    fix: lru_cache annotation doesn't work with a property
+    this hack is only needed for the property, so type annotations are as they are
+    """
+
+    def wrapper(func: T) -> T:
+        return functools.lru_cache(maxsize, typed)(func)  # type: ignore
+
+    return wrapper