desktop/docs/device-auto-refresh-implementation.md

LED Strip Test Device Auto-Refresh Implementation

Overview

Implemented automatic refresh functionality for the device dropdown in the LED strip test interface. The device list now updates in real-time when devices are discovered, connected, or disconnected.

Changes Made

1. Frontend Changes (src/components/led-strip-test/led-strip-test.tsx)

Added Event Listener Import

import { listen } from '@tauri-apps/api/event';

Enhanced Device Loading Logic

• Initial Load: Still loads devices on component mount using get_boards()
• Real-time Updates: Added listener for boards_changed events from backend
• Smart Selection: Automatically handles device selection when devices are added/removed:
  • If current device disconnects, automatically selects first available device
  • If no device was selected and devices become available, selects the first one
  • Properly cleans up event listeners on component unmount

Improved UI Display

• Device Count: Shows number of devices found in label
• Connection Status: Each device option shows:
  • Status icon (🟢 Connected, 🟡 Connecting, 🔴 Disconnected)
  • Device name and address
  • Connection status text
• Empty State: Shows "Searching..." when no devices found

Type Safety Improvements

• Updated BoardInfo interface to match backend types
• Proper handling of connect_status union type
• Type-safe status checking functions

2. Backend Integration

The implementation leverages existing backend infrastructure:

• UdpRpc Manager: Continuously searches for devices via mDNS
• Device Monitoring: Checks device connectivity every second
• Event Broadcasting: Sends boards_changed events to frontend
• Status Tracking: Maintains real-time connection status for each device

Technical Details

Event Flow

1. Backend UdpRpc discovers devices via mDNS service discovery
2. Backend monitors device connectivity with periodic health checks
3. Backend broadcasts boards_changed events when device list changes
4. Frontend listens for events and updates UI automatically
5. Frontend handles device selection logic intelligently

Connection Status Types

• Connected: Device is responding to ping requests
• Connecting: Device is in retry state (with retry count)
• Disconnected: Device is not responding

Error Handling

• Graceful fallback if initial device load fails
• Proper cleanup of event listeners
• Maintains UI state consistency during device changes

Benefits

1. Real-time Updates: No need to manually refresh device list
2. Better UX: Visual indicators for device status
3. Automatic Recovery: Handles device disconnections gracefully
4. Type Safety: Proper TypeScript types prevent runtime errors
5. Performance: Efficient event-driven updates instead of polling

Implementation Status

✅ Completed: LED Strip Test device dropdown auto-refresh ✅ Already Implemented: Board Index page auto-refresh (was already working) ✅ Type Safety: Fixed TypeScript type definitions for BoardInfo ✅ UI Improvements: Added status indicators and device count display

Testing

To test the functionality:

1. Start the application with npm run tauri dev
2. Navigate to LED Strip Test page
3. Observe device list updates as devices come online/offline
4. Verify status indicators show correct connection states:
   • 🟢 Connected devices
   • 🟡 Connecting devices (with retry count)
   • 🔴 Disconnected devices
5. Test device selection behavior when devices disconnect
6. Check that device count is displayed in the label

Code Quality

• ✅ No TypeScript errors
• ✅ Proper event listener cleanup
• ✅ Type-safe status checking
• ✅ Consistent with existing codebase patterns
• ✅ Follows SolidJS best practices

Future Enhancements

• Add device refresh button for manual refresh
• Show device discovery progress indicator
• Add device connection retry controls
• Display device ping latency information
• Add device connection history/logs