Fix tasks cancelation

src/app/services/fl_downloader.py

@@ -1,5 +1,5 @@
-from typing import Optional
-
+from asyncio.exceptions import CancelledError
+from typing import Optional, cast
 import asyncio
 
 import httpx
@@ -82,6 +82,27 @@ class FLDownloader(BaseDownloader):
 
             return response.content, False
 
+    async def _wait_until_some_done(self, tasks: set[asyncio.Task]) -> Optional[tuple[bytes, bool]]:
+        tasks_ = tasks
+
+        while tasks_:
+            done, pending = await asyncio.wait(tasks, return_when=asyncio.FIRST_COMPLETED)
+
+            for task in done:
+                try:
+                    data = cast(tuple[bytes, bool], task.result())
+
+                    for p_task in pending:
+                        p_task.cancel()
+
+                    return data
+                except (NotSuccess, ReceivedHTML):
+                    continue
+
+            tasks_ = pending
+        
+        return None
+
     async def _download_with_converting(self) -> tuple[bytes, bool]:
         tasks = set()
 
@@ -92,24 +113,13 @@ class FLDownloader(BaseDownloader):
                 )
             )
 
-        content: Optional[bytes] = None
-        is_zip: Optional[bool] = None
+        data = await self._wait_until_some_done(tasks)
 
-        while tasks:
-            done, pending = await asyncio.wait(tasks, return_when=asyncio.FIRST_COMPLETED)
-
-            for task in done:
-                try:
-                    content, is_zip = task.result()
-                    break
-                except (NotSuccess, ReceivedHTML):
-                    continue
-
-            tasks = pending
-
-        if content is None or is_zip is None:
+        if data is None:
             raise ValueError
 
+        content, is_zip = data
+
         if is_zip:
             content = await asyncio.get_event_loop().run_in_executor(
                 process_pool_executor, unzip, content, 'fb2'
@@ -147,25 +157,12 @@ class FLDownloader(BaseDownloader):
                 )
             )
         
-        content: Optional[bytes] = None
-        is_zip: Optional[bool] = None
+        data = await self._wait_until_some_done(tasks)
 
-        while tasks:
-            done, pending = await asyncio.wait(tasks, return_when=asyncio.FIRST_COMPLETED)
-
-            for task in done:
-                try:
-                    content, is_zip = task.result()
-
-                    for p_task in pending:
-                        p_task.cancel()
-
-                    break
-                except (NotSuccess, ReceivedHTML, ValueError):
-                    continue
-
-            tasks = pending
+        if data is None:
+            raise ValueError
 
+        content, is_zip = data
 
         if content is None or is_zip is None:
             raise ValueError