Add kaya-session-memcache package for memcached-backed session storage

packages/kaya-session-memcache/tests/test_store.py

@@ -0,0 +1,203 @@
+import unittest
+from datetime import datetime, timezone
+from typing import Optional
+
+import httpx
+from pwo import async_test
+
+from kaya.core import KayaApp, HttpContext
+from kaya.session import Session, SessionMixin
+from kaya.session_memcache import MemcacheSessionStore
+
+
+class FakeClock:
+    def __init__(self, start: float = 1_000_000.0) -> None:
+        self._now = start
+
+    def __call__(self) -> float:
+        return self._now
+
+    def advance(self, seconds: float) -> None:
+        self._now += seconds
+
+
+class StubMemcacheClient:
+    """In-memory stub implementing the aiomcache.Client subset used by the store."""
+
+    def __init__(self, clock: FakeClock) -> None:
+        self._clock = clock
+        self._data: dict[bytes, bytes] = {}
+        self._expires: dict[bytes, float] = {}
+        self.set_exptimes: list[int] = []
+        self.touch_exptimes: list[int] = []
+
+    def _expired(self, key: bytes) -> bool:
+        expires = self._expires.get(key)
+        return expires is not None and self._clock() > expires
+
+    async def get(self, key: bytes) -> Optional[bytes]:
+        if self._expired(key):
+            self._data.pop(key, None)
+            self._expires.pop(key, None)
+            return None
+        return self._data.get(key)
+
+    async def set(self, key: bytes, value: bytes, exptime: int = 0) -> bool:
+        self.set_exptimes.append(exptime)
+        self._data[key] = value
+        if exptime > 0:
+            self._expires[key] = self._clock() + exptime
+        else:
+            self._expires.pop(key, None)
+        return True
+
+    async def delete(self, key: bytes) -> bool:
+        existed = key in self._data
+        self._data.pop(key, None)
+        self._expires.pop(key, None)
+        return existed
+
+    async def touch(self, key: bytes, exptime: int) -> bool:
+        self.touch_exptimes.append(exptime)
+        if self._expired(key) or key not in self._data:
+            return False
+        self._expires[key] = self._clock() + exptime
+        return True
+
+
+class MemcacheSessionStoreTest(unittest.TestCase):
+    clock: FakeClock
+    client: StubMemcacheClient
+    store: MemcacheSessionStore
+
+    def setUp(self) -> None:
+        self.clock = FakeClock()
+        self.client = StubMemcacheClient(self.clock)
+        self.store = MemcacheSessionStore(self.client, clock=self.clock)  # type: ignore[arg-type]
+
+    @async_test
+    async def test_save_and_load_round_trip(self) -> None:
+        session = Session('abc', {'foo': 'bar', 'n': 42})
+        await self.store.save('abc', session)
+        loaded = await self.store.load('abc')
+        self.assertIsNotNone(loaded)
+        assert loaded is not None
+        self.assertEqual('abc', loaded.id)
+        self.assertEqual({'foo': 'bar', 'n': 42}, dict(loaded))
+
+    @async_test
+    async def test_load_unknown_session_returns_none(self) -> None:
+        self.assertIsNone(await self.store.load('missing'))
+
+    @async_test
+    async def test_delete_removes_session(self) -> None:
+        await self.store.save('abc', Session('abc', {'foo': 'bar'}))
+        await self.store.delete('abc')
+        self.assertIsNone(await self.store.load('abc'))
+
+    @async_test
+    async def test_save_with_max_age_expires(self) -> None:
+        await self.store.save('abc', Session('abc', {'foo': 'bar'}), max_age=60)
+        self.assertIsNotNone(await self.store.load('abc'))
+        self.clock.advance(61)
+        self.assertIsNone(await self.store.load('abc'))
+
+    @async_test
+    async def test_save_without_max_age_never_expires(self) -> None:
+        await self.store.save('abc', Session('abc', {'foo': 'bar'}))
+        self.assertEqual([0], self.client.set_exptimes)
+        self.clock.advance(10_000_000)
+        self.assertIsNotNone(await self.store.load('abc'))
+
+    @async_test
+    async def test_load_slides_expiry_when_max_age_given(self) -> None:
+        await self.store.save('abc', Session('abc', {'foo': 'bar'}), max_age=60)
+        self.clock.advance(50)
+        loaded = await self.store.load('abc', max_age=60)
+        self.assertIsNotNone(loaded)
+        self.assertEqual([60], self.client.touch_exptimes)
+        self.clock.advance(50)
+        self.assertIsNotNone(await self.store.load('abc'))
+
+    @async_test
+    async def test_exptime_over_30_days_converted_to_absolute_timestamp(self) -> None:
+        max_age = 40 * 24 * 60 * 60
+        await self.store.save('abc', Session('abc', {'foo': 'bar'}), max_age=max_age)
+        self.assertEqual([int(self.clock()) + max_age], self.client.set_exptimes)
+
+    @async_test
+    async def test_exptime_exactly_30_days_stays_relative(self) -> None:
+        max_age = 30 * 24 * 60 * 60
+        await self.store.save('abc', Session('abc', {'foo': 'bar'}), max_age=max_age)
+        self.assertEqual([max_age], self.client.set_exptimes)
+
+    @async_test
+    async def test_touch_over_30_days_converted_to_absolute_timestamp(self) -> None:
+        max_age = 40 * 24 * 60 * 60
+        await self.store.save('abc', Session('abc', {'foo': 'bar'}), max_age=max_age)
+        self.clock.advance(100)
+        await self.store.load('abc', max_age=max_age)
+        self.assertEqual([int(self.clock()) + max_age], self.client.touch_exptimes)
+
+    @async_test
+    async def test_pickle_round_trip_of_non_json_values(self) -> None:
+        now = datetime(2026, 7, 20, 12, 0, 0, tzinfo=timezone.utc)
+        session = Session('abc', {'when': now, 'blob': b'\x00\x01', 'items': {1, 2, 3}})
+        await self.store.save('abc', session)
+        loaded = await self.store.load('abc')
+        self.assertIsNotNone(loaded)
+        assert loaded is not None
+        self.assertEqual(now, loaded['when'])
+        self.assertEqual(b'\x00\x01', loaded['blob'])
+        self.assertEqual({1, 2, 3}, loaded['items'])
+
+    @async_test
+    async def test_custom_prefix(self) -> None:
+        store = MemcacheSessionStore(self.client, prefix='myapp:sess:', clock=self.clock)  # type: ignore[arg-type]
+        await store.save('abc', Session('abc', {'foo': 'bar'}))
+        self.assertIn(b'myapp:sess:abc', self.client._data)
+        self.assertNotIn(b'kaya:session:abc', self.client._data)
+
+    @async_test
+    async def test_custom_serializer(self) -> None:
+        import json
+
+        store = MemcacheSessionStore(
+            self.client,  # type: ignore[arg-type]
+            dumps=lambda d: json.dumps(d).encode('utf-8'),
+            loads=lambda b: json.loads(b.decode('utf-8')),
+            clock=self.clock,
+        )
+        await store.save('abc', Session('abc', {'foo': 'bar'}))
+        self.assertEqual(b'{"foo": "bar"}', self.client._data[b'kaya:session:abc'])
+        loaded = await store.load('abc')
+        self.assertIsNotNone(loaded)
+        assert loaded is not None
+        self.assertEqual({'foo': 'bar'}, dict(loaded))
+
+
+class MemcacheSessionIntegrationTest(unittest.TestCase):
+    app: KayaApp
+
+    def setUp(self) -> None:
+        store = MemcacheSessionStore(StubMemcacheClient(FakeClock()))  # type: ignore[arg-type]
+        self.app = KayaApp(mixins=[SessionMixin(store)])
+
+        @self.app.GET('/')
+        async def home(ctx: HttpContext) -> None:
+            n = ctx.session.get('visits', 0) + 1
+            ctx.session['visits'] = n
+            await ctx.send_str(200, f'visits: {n}')
+
+    @async_test
+    async def test_session_persists_across_requests(self) -> None:
+        transport = httpx.ASGITransport(app=self.app)
+        async with httpx.AsyncClient(transport=transport, base_url='http://127.0.0.1:80') as client:
+            r = await client.get('/')
+            self.assertEqual(200, r.status_code)
+            self.assertEqual('visits: 1', r.text)
+            self.assertIn('Set-Cookie', r.headers)
+
+            r = await client.get('/')
+            self.assertEqual(200, r.status_code)
+            self.assertEqual('visits: 2', r.text)