Added more details when server send invalid response

CHANGES/1014.misc.rst

@@ -0,0 +1 @@
+Added more detailed error when server response can't be deserialized. This feature will help to debug unexpected responses from the Server

aiogram/client/session/base.py

@@ -7,7 +7,10 @@ from http import HTTPStatus
 from types import TracebackType
 from typing import TYPE_CHECKING, Any, AsyncGenerator, Callable, Final, Optional, Type, Union, cast
 
+from pydantic import ValidationError
+
 from aiogram.exceptions import (
+    ClientDecodeError,
     RestartingTelegram,
     TelegramAPIError,
     TelegramBadRequest,
@@ -64,8 +67,19 @@ class BaseSession(abc.ABC):
         """
         Check response status
         """
-        json_data = self.json_loads(content)
-        response = method.build_response(json_data)
+        try:
+            json_data = self.json_loads(content)
+        except Exception as e:
+            # Handled error type can't be classified as specific error
+            # in due to decoder can be customized and raise any exception
+
+            raise ClientDecodeError("Failed to decode object", e, content)
+
+        try:
+            response = method.build_response(json_data)
+        except ValidationError as e:
+            raise ClientDecodeError("Failed to deserialize object", e, json_data)
+
         if HTTPStatus.OK <= status_code <= HTTPStatus.IM_USED and response.ok:
             return response
 

aiogram/exceptions.py

@@ -1,4 +1,4 @@
-from typing import Optional
+from typing import Any, Optional
 
 from aiogram.methods import TelegramMethod
 from aiogram.methods.base import TelegramType
@@ -104,3 +104,18 @@ class RestartingTelegram(TelegramServerError):
 
 class TelegramEntityTooLarge(TelegramNetworkError):
     url = "https://core.telegram.org/bots/api#sending-files"
+
+
+class ClientDecodeError(AiogramError):
+    def __init__(self, message: str, original: Exception, data: Any) -> None:
+        self.message = message
+        self.original = original
+        self.data = data
+
+    def __str__(self) -> str:
+        original_type = type(self.original)
+        return (
+            f"{self.message}\n"
+            f"Caused from error: {original_type.__module__}.{original_type.__name__}: {self.original}\n"
+            f"Content: {self.data}"
+        )

tests/test_api/test_client/test_session/test_base_session.py

@@ -8,6 +8,7 @@ from aiogram import Bot
 from aiogram.client.session.base import BaseSession, TelegramType
 from aiogram.client.telegram import PRODUCTION, TelegramAPIServer
 from aiogram.exceptions import (
+    ClientDecodeError,
     RestartingTelegram,
     TelegramAPIError,
     TelegramBadRequest,
@@ -183,6 +184,28 @@ class TestBaseSession:
             if error.url:
                 assert error.url in string
 
+    def test_check_response_json_decode_error(self):
+        session = CustomSession()
+        method = DeleteMessage(chat_id=42, message_id=42)
+
+        with pytest.raises(ClientDecodeError, match="JSONDecodeError"):
+            session.check_response(
+                method=method,
+                status_code=200,
+                content="is not a JSON object",
+            )
+
+    def test_check_response_validation_error(self):
+        session = CustomSession()
+        method = DeleteMessage(chat_id=42, message_id=42)
+
+        with pytest.raises(ClientDecodeError, match="ValidationError"):
+            session.check_response(
+                method=method,
+                status_code=200,
+                content='{"ok": "test"}',
+            )
+
     async def test_make_request(self):
         session = CustomSession()