# SSE Refactor: Quick Reference

## File Locations

```
/home/uroma/obsidian-web-interface/
├── services/
│   ├── event-bus.js           ← NEW: Event pub/sub system
│   ├── sse-manager.js         ← NEW: SSE connection management
│   └── claude-service.js      ← MODIFY: Emit events instead of callbacks
├── routes/
│   ├── session-routes.js      ← NEW: Session API endpoints
│   └── sse-routes.js          ← NEW: SSE streaming endpoint
├── middleware/
│   └── validation.js          ← NEW: Request validation middleware
├── public/js/
│   └── sse-client.js          ← NEW: Client-side SSE manager
└── server.js                  ← MODIFY: Register new routes
```

## Key Code Snippets

### 1. EventBus Usage

```javascript
const eventBus = require('./services/event-bus');

// Emit an event
eventBus.emit('session-output', {
  sessionId: 'session-123',
  type: 'stdout',
  content: 'Hello from terminal'
});

// Subscribe to events
const unsubscribe = eventBus.subscribe('session-output', 'session-123', (data) => {
  console.log('Output:', data.content);
});

// Unsubscribe when done
unsubscribe();

// Subscribe to all session events
const unsubAll = eventBus.subscribeToSession('session-123', (data) => {
  console.log('Event:', data._eventType, data);
});
```

### 2. SSE Manager Usage

```javascript
const sseManager = require('./services/sse-manager');

// In route handler
app.get('/api/session/:sessionId/events', (req, res) => {
  const { sessionId } = req.params;
  sseManager.addConnection(sessionId, res, req);
  // Response stays open for streaming
});

// Get connection stats
const stats = sseManager.getStats();
// { totalSessions: 5, totalConnections: 12, ... }

// Get connection count for specific session
const count = sseManager.getConnectionCount('session-123');

// Broadcast to all connections for a session
sseManager.broadcastToSession('session-123', {
  type: 'custom-event',
  data: 'hello'
});
```

### 3. Client-Side Usage

```javascript
// Include script
<script src="/js/sse-client.js"></script>

// Create connection
const eventStream = new SessionEventStream('session-123', {
  reconnectInterval: 2000,
  maxReconnectAttempts: 20
});

// Listen for events
eventStream.on('output', (data) => {
  console.log('Output:', data.content);
});

eventStream.on('error', (data) => {
  console.error('Error:', data.error);
});

eventStream.on('connected', () => {
  console.log('Connected!');
});

// Send command via REST API
async function sendCommand(command) {
  await fetch(`/api/session/session-123/prompt`, {
    method: 'POST',
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify({ command })
  });
}

// Cleanup
eventStream.disconnect();
```

### 4. Validation Middleware

```javascript
const { validateSessionId, validateCommand } = require('./middleware/validation');

// Validate session ID parameter
router.get('/api/session/:sessionId/status', validateSessionId, (req, res) => {
  // req.sessionContext is available
  res.json(req.sessionContext);
});

// Validate request body
router.post('/api/session/:sessionId/prompt', validateSessionId, validateCommand, (req, res) => {
  // req.body.command is validated
  const { command } = req.body;
});
```

## API Endpoints

### SSE Endpoints

| Endpoint | Method | Description |
|----------|--------|-------------|
| `/api/session/:sessionId/events` | GET | SSE event stream |
| `/api/session/:sessionId/events/status` | GET | Connection status |
| `/api/sse/stats` | GET | Global SSE stats |

### Session Endpoints

| Endpoint | Method | Description |
|----------|--------|-------------|
| `/api/session/:sessionId/prompt` | POST | Send command |
| `/api/session/:sessionId/status` | GET | Session status |
| `/api/session/:sessionId/context` | GET | Session context |
| `/api/session/:sessionId/operations/preview` | POST | Preview operations |
| `/api/session/:sessionId/operations/execute` | POST | Execute operations |
| `/api/session/:sessionId` | DELETE | Delete session |
| `/api/session/:sessionId/duplicate` | POST | Duplicate session |
| `/api/session/:sessionId/fork` | POST | Fork session |
| `/api/session/:sessionId/move` | POST | Move to project |

## Event Types

| Event Type | Description | Fields |
|------------|-------------|--------|
| `connected` | SSE connection established | `sessionId`, `timestamp` |
| `session-output` | Output from Claude | `type`, `content`, `sessionId` |
| `session-error` | Session error | `error`, `code`, `recoverable` |
| `session-status` | Status update | `status`, `pid`, `uptime` |
| `operations-detected` | Operations found | `operations[]`, `response` |
| `operations-executed` | Operations completed | `results[]` |
| `operations-error` | Operations failed | `error`, `operations[]` |
| `approval-request` | Approval needed | `approvalId`, `command`, `explanation` |
| `approval-confirmed` | Approval handled | `approvalId`, `approved` |
| `approval-expired` | Approval timeout | `approvalId` |
| `command-sent` | Command sent | `sessionId`, `command` |
| `session-created` | New session | `sessionId`, `mode` |
| `session-deleted` | Session removed | `sessionId` |

## Migration Checklist

### Phase 1: Infrastructure (1-2 weeks)
- [ ] Implement EventBus service
- [ ] Implement SSE Manager service
- [ ] Create session routes
- [ ] Create SSE routes
- [ ] Create validation middleware
- [ ] Add routes to server.js
- [ ] Write unit tests
- [ ] Deploy to staging

### Phase 2: Client Migration (2-3 weeks)
- [ ] Create SSE client library
- [ ] Update IDE UI for new sessions
- [ ] Add feature flag for SSE vs WebSocket
- [ ] A/B test SSE vs WebSocket
- [ ] Monitor metrics
- [ ] Fix bugs
- [ ] Document findings

### Phase 3: Deprecation (1-2 weeks)
- [ ] Add deprecation warnings to WebSocket
- [ ] Update documentation
- [ ] Redirect old routes
- [ ] Communicate with users

### Phase 4: Cleanup (1 week)
- [ ] Remove WebSocket code
- [ ] Remove legacy client code
- [ ] Clean up unused dependencies
- [ ] Final regression test

## Monitoring Endpoints

```bash
# Event bus metrics
curl http://localhost:3010/api/debug/metrics

# SSE connection stats
curl http://localhost:3010/api/sse/stats

# Session status
curl http://localhost:3010/api/session/SESSION_ID/status

# Connection count for session
curl http://localhost:3010/api/session/SESSION_ID/events/status
```

## Configuration

### Server-Side (no config needed)

EventBus and SSEManager work out of the box with sensible defaults.

### Client-Side Options

```javascript
const options = {
  reconnectInterval: 1000,      // Initial reconnect delay (ms)
  maxReconnectInterval: 30000,   // Max reconnect delay (ms)
  reconnectDecay: 1.5,           // Exponential backoff
  maxReconnectAttempts: 10,      // Max reconnect attempts
  heartbeatTimeout: 60000        // Heartbeat timeout (ms)
};

const stream = new SessionEventStream('session-123', options);
```

## Testing

```bash
# Test SSE connection
curl -N http://localhost:3010/api/session/SESSION_ID/events

# Test with event output
curl -N -H "Accept: text/event-stream" \
  http://localhost:3010/api/session/SESSION_ID/events

# Send command
curl -X POST http://localhost:3010/api/session/SESSION_ID/prompt \
  -H "Content-Type: application/json" \
  -d '{"command":"echo hello"}'

# Check metrics
curl http://localhost:3010/api/debug/metrics | jq
```

## nginx Configuration

```nginx
location /api/session/ {
  proxy_buffering off;
  proxy_cache off;
  proxy_pass http://localhost:3010;
  proxy_http_version 1.1;
  proxy_set_header Connection '';
  proxy_set_header Cache-Control no-cache;
  proxy_set_header X-Accel-Buffering no;
  proxy_read_timeout 86400s;
  proxy_send_timeout 86400s;
}
```

## Common Issues

| Issue | Solution |
|-------|----------|
| Connection closes immediately | Check nginx buffering settings |
| No events received | Verify session ID is valid |
| Frequent reconnects | Increase heartbeat timeout |
| Memory leaks | Ensure listeners are unsubscribed |
| 404 on session endpoint | Check session exists, validate format |

## Rollback Plan

If issues occur:

1. **Phase 1-2:** Disable new routes, keep using WebSocket
2. **Phase 3:** Re-enable WebSocket as fallback
3. **Any phase:** Revert git commit, restart services

## Support

- Full plan: `SSE_REFACTOR_PLAN.md`
- Implementation guide: `SSE_IMPLEMENTATION_GUIDE.md`
- Code: `services/event-bus.js`, `services/sse-manager.js`
- Routes: `routes/session-routes.js`, `routes/sse-routes.js`

---

Last Updated: 2025-01-21
Version: 1.0