Improve performance of fetching the content-length for web responses (#…

…9448)

Co-authored-by: Sam Bull <git@sambull.org>

aiohttp/helpers.py

@@ -747,11 +747,7 @@ def charset(self) -> Optional[str]:
     def content_length(self) -> Optional[int]:
         """The value of Content-Length HTTP header."""
         content_length = self._headers.get(hdrs.CONTENT_LENGTH)
-
-        if content_length is not None:
-            return int(content_length)
-        else:
-            return None
+        return None if content_length is None else int(content_length)
 
 
 def set_result(fut: "asyncio.Future[_T]", result: _T) -> None:

aiohttp/web_response.py

@@ -646,7 +646,7 @@ def content_length(self) -> Optional[int]:
             return None
 
         if hdrs.CONTENT_LENGTH in self._headers:
-            return super().content_length
+            return int(self._headers[hdrs.CONTENT_LENGTH])
 
         if self._compressed_body is not None:
             # Return length of the compressed body