fix get_session_remaining_seconds() for rolling sessions

`get_session_remaining_seconds()` should return `last_update + lifetime - now` instead of `created + lifetime - now`.

Fix mypy: use FixtureRequest instead of SubRequest

`SubRequest` is a subclass of `FixtureRequest`, but is currently private
so pytest-asyncio uses `Any` instead. However, `FixtureRequest` typing
is sufficient for our needs, so can use that instead.

starsessions/middleware.py

@@ -66,7 +66,7 @@ async def __call__(self, scope: Scope, receive: Receive, send: Send) -> None:
 
         connection = HTTPConnection(scope)
         session_id = connection.cookies.get(self.cookie_name)
-        handler = SessionHandler(connection, session_id, self.store, self.serializer, self.lifetime)
+        handler = SessionHandler(connection, session_id, self.rolling, self.store, self.serializer, self.lifetime)
 
         scope["session"] = LoadGuard()
         scope["session_handler"] = handler

starsessions/session.py

@@ -72,7 +72,10 @@ def get_session_remaining_seconds(connection: HTTPConnection) -> int:
     """Get total seconds remaining before this session expires."""
     now = time.time()
     metadata = get_session_metadata(connection)
-    return int((metadata["created"] + metadata["lifetime"]) - now)
+    # use "last_update" if rolling session, otherwise use "created"
+    rolling = metadata.get("rolling", False)
+    last_update = metadata["last_update"] if rolling and "last_update" in metadata else metadata["created"]
+    return int((last_update + metadata["lifetime"]) - now)
 
 
 class SessionHandler:
@@ -86,12 +89,14 @@ def __init__(
         self,
         connection: HTTPConnection,
         session_id: typing.Optional[str],
+        rolling: bool,
         store: SessionStore,
         serializer: Serializer,
         lifetime: int,
     ) -> None:
         self.connection = connection
         self.session_id = session_id
+        self.rolling = rolling
         self.store = store
         self.serializer = serializer
         self.is_loaded = False
@@ -115,7 +120,12 @@ async def load(self) -> None:
             )
 
         # read and merge metadata
-        metadata = {"lifetime": self.lifetime, "created": time.time(), "last_access": time.time()}
+        metadata = {
+            "lifetime": self.lifetime,
+            "created": time.time(),
+            "last_access": time.time(),
+            "rolling": self.rolling,
+        }
         metadata.update(data.pop("__metadata__", {}))
         metadata.update({"last_access": time.time()})  # force update
         self.metadata = metadata  # type: ignore[assignment]
@@ -126,6 +136,8 @@ async def load(self) -> None:
         self.initially_empty = len(self.connection.session) == 0
 
     async def save(self, remaining_time: int) -> str:
+        if self.rolling and self.metadata:
+            self.metadata["last_update"] = time.time()
         self.connection.session.update({"__metadata__": self.metadata})
 
         self.session_id = await self.store.write(

starsessions/types.py

@@ -5,3 +5,4 @@ class SessionMetadata(typing.TypedDict):
     lifetime: int
     created: float  # timestamp
     last_access: float  # timestamp
+    last_update: float  # timestamp

tests/backends/test_redis.py

@@ -1,7 +1,7 @@
 import os
 import pytest
 import redis.asyncio
-from pytest_asyncio.plugin import SubRequest
+from pytest import FixtureRequest
 
 from starsessions import ImproperlyConfigured
 from starsessions.stores.base import SessionStore
@@ -13,7 +13,7 @@ def redis_key_callable(session_id: str) -> str:
 
 
 @pytest.fixture(params=["prefix_", redis_key_callable], ids=["using string", "using redis_key_callable"])
-def redis_store(request: SubRequest) -> SessionStore:
+def redis_store(request: FixtureRequest) -> SessionStore:
     redis_key = request.param
     url = os.environ.get("REDIS_URL", "redis://localhost")
     return RedisStore(url, prefix=redis_key)

tests/test_metadata.py

@@ -37,6 +37,7 @@ async def app(scope: Scope, receive: Receive, send: Send) -> None:
             "created": 1660556520,
             "last_access": 1660556520,
             "lifetime": 1209600,
+            "rolling": False,
         }
 
 
@@ -59,6 +60,7 @@ async def app(scope: Scope, receive: Receive, send: Send) -> None:
             "created": 42,
             "last_access": 1660556520,
             "lifetime": 0,
+            "rolling": False,
         }
 
 
@@ -79,11 +81,13 @@ async def app(scope: Scope, receive: Receive, send: Send) -> None:
             "created": 1660556520,
             "last_access": 1660556520,
             "lifetime": 1209600,
+            "rolling": False,
         }
 
     with mock.patch("time.time", lambda: 1660556000):
         assert client.get("/", cookies={"session": "session_id"}).json() == {
             "created": 1660556520,
             "last_access": 1660556000,
             "lifetime": 1209600,
+            "rolling": False,
         }

tests/test_rolling_session.py

@@ -7,6 +7,7 @@
 from unittest import mock
 
 from starsessions import SessionMiddleware, SessionStore, load_session
+from starsessions.session import get_session_remaining_seconds
 
 
 @pytest.mark.asyncio
@@ -19,21 +20,22 @@ async def app(scope: Scope, receive: Receive, send: Send) -> None:
         await load_session(connection)
         response = JSONResponse(connection.session)
         await response(scope, receive, send)
+        # the session has been rolled again to last for another 10 seconds
+        assert get_session_remaining_seconds(connection) == session_lifetime
 
     app = SessionMiddleware(app, store=store, lifetime=10, rolling=True)
     client = TestClient(app)
 
     current_time = time.time()
 
-    # it must set max-age = 10
     with mock.patch("time.time", lambda: current_time):
         response = client.get("/", cookies={"session": "session_id"})
-        first_max_age = next(cookie for cookie in response.cookies if cookie.name == "session").expires
+        first_expiration_date = next(cookie for cookie in response.cookies if cookie.name == "session").expires
 
-    # it must set max-age = 10 regardless of any previous value
+    # fast forward 2 seconds
     with mock.patch("time.time", lambda: current_time + 2):
         response = client.get("/", cookies={"session": "session_id"})
-        second_max_age = next(cookie for cookie in response.cookies if cookie.name == "session").expires
+        second_expiration_date = next(cookie for cookie in response.cookies if cookie.name == "session").expires
 
-    # the expiration date of the second response must be larger
-    assert second_max_age > first_max_age
+    # the expiration date of the cooke in the second response must be extended by 2 seconds
+    assert second_expiration_date - first_expiration_date == 2

tests/test_session.py

@@ -22,7 +22,9 @@ def test_regenerate_session_id(store: SessionStore, serializer: Serializer) -> N
     base_session_id = "some_id"
     connection = HTTPConnection(scope)
     connection.scope["session"] = {}
-    connection.scope["session_handler"] = SessionHandler(connection, base_session_id, store, serializer, lifetime=60)
+    connection.scope["session_handler"] = SessionHandler(
+        connection, base_session_id, False, store, serializer, lifetime=60
+    )
 
     session_id = regenerate_session_id(connection)
     assert session_id
@@ -34,7 +36,9 @@ def test_get_session_id(store: SessionStore, serializer: Serializer) -> None:
     base_session_id = "some_id"
     connection = HTTPConnection(scope)
     connection.scope["session"] = {}
-    connection.scope["session_handler"] = SessionHandler(connection, base_session_id, store, serializer, lifetime=60)
+    connection.scope["session_handler"] = SessionHandler(
+        connection, base_session_id, False, store, serializer, lifetime=60
+    )
 
     session_id = get_session_id(connection)
     assert session_id == base_session_id
@@ -45,7 +49,9 @@ def test_get_session_handler(store: SessionStore, serializer: Serializer) -> Non
     base_session_id = "some_id"
     connection = HTTPConnection(scope)
     connection.scope["session"] = {}
-    connection.scope["session_handler"] = SessionHandler(connection, base_session_id, store, serializer, lifetime=60)
+    connection.scope["session_handler"] = SessionHandler(
+        connection, base_session_id, False, store, serializer, lifetime=60
+    )
 
     assert get_session_handler(connection) == connection.scope["session_handler"]
 
@@ -56,7 +62,9 @@ async def test_load_session(store: SessionStore, serializer: Serializer) -> None
     base_session_id = "session_id"
     connection = HTTPConnection(scope)
     connection.scope["session"] = {}
-    connection.scope["session_handler"] = SessionHandler(connection, base_session_id, store, serializer, lifetime=60)
+    connection.scope["session_handler"] = SessionHandler(
+        connection, base_session_id, False, store, serializer, lifetime=60
+    )
 
     await store.write("session_id", b'{"key": "value"}', lifetime=60, ttl=60)
     await load_session(connection)