Ran the test suites and fixed messages.

starlette/middleware/sessions.py

@@ -1,7 +1,7 @@
 import json
 import typing
-from datetime import datetime, timedelta, timezone
 from base64 import b64decode, b64encode
+from datetime import datetime, timedelta, timezone
 
 import itsdangerous
 from itsdangerous.exc import BadSignature, SignatureExpired
@@ -22,7 +22,7 @@ def __init__(
         same_site: typing.Literal["lax", "strict", "none"] = "lax",
         https_only: bool = False,
         persist_session: bool = False,
-        auto_refresh_window: int = 0, # seconds, default 0 to not auto refresh, 240 seconds for 4 minute window to refresh
+        auto_refresh_window: int = 0, 
         domain: typing.Optional[str] = None,
     ) -> None:
         self.app = app
@@ -39,12 +39,12 @@ def __init__(
             self.security_flags += f"; domain={domain}"
 
 
-    def decode_cookie(self,cookie):
-        result = {"session": {}}
+    def decode_cookie(self,cookie: bytes) -> typing.Dict[str,typing.Any]:
+        result: typing.Dict[str, typing.Any] =  {"session": {}}
         try:
-            data = self.signer.unsign(cookie, max_age=self.max_age,return_timestamp=True)
-            result["session"] = json.loads(b64decode(data[0])) #first element of the data array is the json
-            result["datetime"] = data[1] #second element of the data array returned is a datetime object.
+            data = self.signer.unsign(cookie,max_age=self.max_age,return_timestamp=True)
+            result["session"] = json.loads(b64decode(data[0])) 
+            result["datetime"] = data[1] #DateTime obj
         except (BadSignature, SignatureExpired):
             return result
         return result
@@ -58,14 +58,14 @@ async def __call__(self, scope: Scope, receive: Receive, send: Send) -> None:
         update_session = True
 
         if self.session_cookie in connection.cookies:
-            data = self.decode_cookie(connection.cookies[self.session_cookie].encode("utf-8"))
+            data = self.decode_cookie(connection.cookies[self.session_cookie].encode("utf-8")) # noqa E501
             scope["session"] = data["session"]
-            scope["exp"] = data["datetime"] + timedelta(seconds=self.max_age)
+            scope["exp"] = data["datetime"] + timedelta(seconds=self.max_age) # type: ignore[arg-type]
 
             if self.auto_refresh_window:
                 now = datetime.now(timezone.utc)
                 #if the expiry date not inside of the expiry window, do not update.
-                if not (now >= (scope["exp"] - timedelta(seconds=self.auto_refresh_window)) and now <= scope["exp"]):
+                if not (now >= (scope["exp"] - timedelta(seconds=self.auto_refresh_window)) and now <= scope["exp"]): # noqa E501
                     update_session = False
             elif self.persist_session:
                     update_session = False
@@ -77,8 +77,8 @@ async def send_wrapper(message: Message) -> None:
             session_changed = False
             if message["type"] == "http.response.start":
                 if self.session_cookie in connection.cookies:
-                    previous_session_data = self.decode_cookie(connection.cookies[self.session_cookie].encode("utf-8"))
-                    if (previous_session_data["session"] and scope["session"]) and previous_session_data["session"] != scope["session"]:
+                    previous_session_data = self.decode_cookie(connection.cookies[self.session_cookie].encode("utf-8")) # noqa E501
+                    if (previous_session_data["session"] and scope["session"]) and previous_session_data["session"] != scope["session"]: # noqa E501
                         session_changed = True 
 
                 if scope["session"] and (update_session or session_changed):
@@ -95,7 +95,6 @@ async def send_wrapper(message: Message) -> None:
                     )
                     headers.append("Set-Cookie", header_value)
                 elif update_session and not scope["session"]:
-                    # The session is cleared. BadSignature/SignatureExpired or the initial scope session was empty
                     headers = MutableHeaders(scope=message)
                     header_value = "{session_cookie}={data}; path={path}; {expires}{security_flags}".format(  # noqa E501
                         session_cookie=self.session_cookie,