Speed up finding the reason if its unset (#9175)

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
(cherry picked from commit 756fae8)

CHANGES/9175.misc.rst

@@ -0,0 +1 @@
+9174.misc.rst

aiohttp/web_response.py

@@ -42,6 +42,8 @@
 from .payload import Payload
 from .typedefs import JSONEncoder, LooseHeaders
 
+REASON_PHRASES = {http_status.value: http_status.phrase for http_status in HTTPStatus}
+
 __all__ = ("ContentCoding", "StreamResponse", "Response", "json_response")
 
 
@@ -102,7 +104,7 @@ def __init__(
  else:
  self._headers = CIMultiDict()
 
- self.set_status(status, reason)
+ self._set_status(status, reason)
 
  @property
  def prepared(self) -> bool:
@@ -139,13 +141,13 @@ def set_status(
  assert (
  not self.prepared
  ), "Cannot change the response status code after the headers have been sent"
- self._status = int(status)
+ self._set_status(status, reason)
+
+ def _set_status(self, status: int, reason: Optional[str]) -> None:
+ self._status = status
  if reason is None:
- try:
- reason = HTTPStatus(self._status).phrase
- except ValueError:
- reason = ""
- if "\n" in reason:
+ reason = REASON_PHRASES.get(self._status, "")
+ elif "\n" in reason:
  raise ValueError("Reason cannot contain \\n")
  self._reason = reason
 

tests/test_web_response.py

@@ -933,6 +933,14 @@ def test_set_status_with_reason() -> None:
  assert "Everything is fine!" == resp.reason
 
 
+def test_set_status_with_empty_reason() -> None:
+ resp = StreamResponse()
+
+ resp.set_status(200, "")
+ assert resp.status == 200
+ assert resp.reason == ""
+
+
 async def test_start_force_close() -> None:
  req = make_request("GET", "/")
  resp = StreamResponse()