serverpod-caching

# Serverpod Caching In-memory and optional Redis caches via `session.caches`. Cached objects must be serializable models or primitives supported by Serverpod. ## Cache types - **`session.caches.local`** — in-memory, current server instance - **`session.caches.localPrio`** — in-memory, for frequently accessed entries - **`session.caches.global`** — Redis-backed, shared across instances (requires Redis config; do not use without Redis enabled) - **`session.caches.query`** — local query cache used by generated database helpers ## Basic usage ```dart await session.caches.local.put('UserData-$userId', userData, lifetime: Duration(minutes: 5)); var userData = await session.caches.local.get<UserData>('UserData-$userId'); ``` ## CacheMissHandler Load on miss and store automatically: ```dart var userData = await session.caches.local.get( 'UserData-$userId', CacheMissHandler( () async => UserData.db.findById(session, userId), lifetime: Duration(minutes: 5), ), ); ``` Returns `null` if the handler returns `null` (nothing stored). ## Collections and primitives ```dart await session.caches.local.put('userCount', 17, lifetime: Duration(minutes: 5)); var count = await session.caches.local.get<int>('userCount'); ``` If relevant set a **lifetime** to avoid unbounded growth. Use stable, unique keys (e.g. `'EntityName-$id'`). ## Pitfalls - `session.caches.global` asserts Redis is enabled; it is not a safe no-op fallback. - Cache groups (`put(..., group: 'name')` + `invalidateGroup('name')`) only work on the local caches. `invalidateGroup` throws `UnimplementedError` on the Redis-backed global cache, so invalidate those entries by key with `invalidateKey`.