# SignalRs

Server-side SignalR hub infrastructure: hub base class, session management, data source with change tracking, and client broadcast service.

> **Architecture:** For full dispatch flow, tag system, and tech debt documentation see `AyCode.Services/docs/SIGNALR.md`.

## Key Files

### Hub
- **`AcWebSignalRHubBase.cs`** — Abstract hub extending `Hub<IAcSignalRHubItemServer>`. Manages connection lifecycle, message dispatch via `DynamicMethodRegistry`, binary/JSON parameter deserialization. Response methods: `ResponseToCaller()`, `SendMessageToOthers()`, `SendMessageToUserIdInternal()`.
- **`IAcSignalRHubItemServer.cs`** — Server hub interfaces: `IAcSignalRHubItemServer`, `IAcSignalRHubServer`.
- **`AcLoggerSignalRHub.cs`** — Specialized hub for receiving log items via SignalR (`AddLogItem()`).

### Session & Broadcast
- **`AcSessionService.cs`** — Generic session manager with `ConcurrentDictionary<TSessionItemId, TSessionItem>`.
- **`IAcSessionItem.cs`** — Session item interface with `SessionId` property.
- **`AcSignalRSendToClientService.cs`** — Abstract broadcast service: `SendMessageToClient()`, `SendMessageToAllClients()`, `SendMessageToConnection()`, `SendMessageToUser()`.

### Data Source

> **Full specification:** `AyCode.Services.Server/docs/SIGNALR_DATASOURCE.md`

- **`AcSignalRDataSource.cs`** — Generic real-time collection (`AcSignalRDataSource<TDataItem, TId, TIList>`) implementing `IList<T>` with full CRUD and change tracking.
  - **Change tracking:** `TrackingItem<T, TId>` wraps each modified item with `TrackingState` + `OriginalValue` for rollback. `ChangeTracking<T, TId>` manages the tracking list.
  - **Loading:** `LoadDataSource()` (sync), `LoadDataSourceAsync()` (async callback), `LoadItem(id)` (single). Binary path uses `BinaryToMerge()` for `AcObservableCollection` (batch UI update via `BeginUpdate/EndUpdate`).
  - **Saving:** `SaveChanges()` iterates tracked items, posts each via CRUD tag, rollbacks on failure. `SaveItem()` for individual saves.
  - **Sync state:** `IsSyncing` (Interlocked counter) + `OnSyncingStateChanged` event for UI loading indicators.
  - **Locking:** `object _syncRoot` (sync ops) + `SemaphoreSlim _asyncLock` (async ops). `GetEnumerator()` returns safe copy.
  - **Working reference list:** `SetWorkingReferenceList()` allows external list to become inner storage (zero-copy).
  - **Context:** `ContextIds` (object[]) + `FilterText` (string) sent with GetAll requests for server-side filtering.

### Utilities
- **`ExtensionMethods.cs`** — `InvokeMethod()` — invokes methods and unwraps `Task`/`Task<T>`/`ValueTask` results.
- **`TrackingItemHelpers.cs`** — Deep clone helpers: `JsonClone<T>()`, `ReflectionClone<T>()`.