Change normalize_path_middleware redirect from 301 -> 308 (#3579)

CHANGES/3579.bugfix

@@ -0,0 +1,4 @@
+Change normalize_path_middleware to use 308 redirect instead of 301.
+
+This behavior should prevent clients from being unable to use PUT/POST
+methods on endpoints that are redirected because of a trailing slash.

CONTRIBUTORS.txt

@@ -61,6 +61,7 @@ Cong Xu
 Damien Nadé
 Dan Xu
 Daniel García
+Daniel Grossmann-Kavanagh
 Daniel Nelson
 Danny Song
 David Bibb

aiohttp/web_middlewares.py

@@ -2,7 +2,7 @@
 import warnings
 from typing import TYPE_CHECKING, Awaitable, Callable, Tuple, Type, TypeVar
 
-from .web_exceptions import HTTPMove, HTTPMovedPermanently
+from .web_exceptions import HTTPMove, HTTPPermanentRedirect
 from .web_request import Request
 from .web_response import StreamResponse
 from .web_urldispatcher import SystemRoute
@@ -45,7 +45,7 @@ def middleware(f: _Func) -> _Func:
 def normalize_path_middleware(
         *, append_slash: bool=True, remove_slash: bool=False,
         merge_slashes: bool=True,
-        redirect_class: Type[HTTPMove]=HTTPMovedPermanently) -> _Middleware:
+        redirect_class: Type[HTTPMove]=HTTPPermanentRedirect) -> _Middleware:
     """
     Middleware factory which produces a middleware that normalizes
     the path of a request. By normalizing it means:

docs/web_reference.rst

@@ -2826,7 +2826,7 @@ Normalize path middleware
                                         append_slash=True, \
                                         remove_slash=False, \
                                         merge_slashes=True, \
-                                        redirect_class=HTTPMovedPermanently)
+                                        redirect_class=HTTPPermanentRedirect)
 
    Middleware factory which produces a middleware that normalizes
    the path of a request. By normalizing it means: