ef1f9eade2
Multi-axis lift to ship-quality after a full review:
Security
- ApiKeyManager: per-install random API key, persisted via SharedPreferences
with synchronous first-write; threaded into uvicorn via the
LEDGRAB_AUTH__API_KEYS env var; embedded in QR as a URL fragment (#k=)
so it never appears in HTTP requests or server logs; frontend reads
location.hash on first visit and strips it via history.replaceState
- Root.runAsRoot(argv: Array<String>) overload with POSIX shell-quoting to
eliminate the shell-injection footgun (= excluded from unquoted-safe set)
- UsbSerialBridge: ContextCompat.RECEIVER_NOT_EXPORTED + intent.package
check in the broadcast receiver for defence-in-depth across API levels
- Release builds refuse to silently fall back to debug keystore; require
ANDROID_KEYSTORE_* env vars or explicit
ANDROID_ALLOW_DEBUG_SIGNED_RELEASE=1
- Crash log retention capped at 10 entries
- Fatal-error stack trace hidden behind a toggle on the error screen
Performance
- ScreenCapture / RootScreenrecord reuse a single RGBA ByteArray per
pipeline instead of allocating per frame — eliminates ~15 MB/s GC churn
at 30 fps on low-end TV boxes
- Frame pacer switched from System.currentTimeMillis() + integer division
(~30.3 fps drift) to SystemClock.elapsedRealtimeNanos with a catch-up
accumulator
- ScreenCapture computes capture dimensions from source aspect ratio so
non-16:9 displays don't get squashed
- RootScreenrecord input pump backs off 5 ms when MediaCodec is starved,
ending a tight spin that burned a CPU core on decoder stalls
- QR cached by URL — onResume from background no longer rebuilds the
560×560 bitmap each time
- ApiKey commit() pre-warmed off Main on app startup
Compatibility
- compileSdk / targetSdk bumped to 35 (Play Store requirement)
- armeabi-v7a build path added to build script + conditionally included
in gradle splits when the matching wheel is present in android/wheels/
- Foreground service type declared as mediaProjection|specialUse with
PROPERTY_SPECIAL_USE_FGS_SUBTYPE rationale; promotion via
ServiceCompat.startForeground with the correct type per mode
- NetworkUtils picks Ethernet > Wi-Fi > VPN > cellular instead of just
activeNetwork — fixes wrong-URL on TV boxes with both Ethernet + Wi-Fi
- enableOnBackInvokedCallback=true for Android 15 predictive-back
- Splash screen API via androidx.core:core-splashscreen — hides Chaquopy
stdlib unpack delay on cold first launch
UI / UX
- All previously hardcoded English strings (root prompt, permission
denial, fatal-error screen, notification text) now localised across
en/ru/zh
- Monochrome notification icon (was a colored launcher → gray blob in
status bar)
- 320×180 TV banner (was the square launcher → squashed on Leanback row)
- ViewStub-based running panel (deferred inflation)
- ObjectAnimator pulse on the Running status dot for liveness feedback
- "Starting…" button state while root is being probed
- Autostart checkbox hidden entirely on unrooted devices
- "No network" status when getLocalIpAddress returns null
- QR fallback hint text
- Animator cancelled in onStop to avoid leaking view hierarchy
Lifecycle hardening (from review)
- RootScreenrecord: processLock serialises EOF respawn vs concurrent
stop() to prevent orphaned screenrecord processes
- CaptureService.restartRootPipeline: publish-before-start under
@Synchronized to close the orphan window during watchdog restarts
- ScreenCapture.MediaProjection.Callback.onStop just flips
running=false instead of calling stop() (which self-joined
captureThread and hung 500 ms)
- updateUI early-returns when lateinit not initialised (fatal-error path)
- Watchdog give-up bound fixed (>= instead of >, was allowing 4 attempts)
server/android_entry.py accepts an optional api_key, sets
LEDGRAB_AUTH__API_KEYS={"android":<key>} as JSON before any LedGrab
import, logs a clear error if pydantic-settings parsing doesn't land
the value back in config (defensive guard against future settings
behaviour drift).
server/static/js/app.ts: bootstrap reads #k= from location.hash,
persists to localStorage, then strips via history.replaceState.
Two independent code-review passes; 147 relevant server tests still
pass; TypeScript and ruff clean.
LedGrab - Server
High-performance FastAPI server that captures screen content and controls WLED devices for ambient lighting.
Overview
The server component provides:
- 🎯 Real-time Screen Capture - Multi-monitor support with configurable FPS
- 🎨 Advanced Processing - Border pixel extraction with color correction
- 🔧 Flexible Calibration - Map screen edges to any LED layout
- 🌐 REST API - Complete control via 25+ REST endpoints
- 💾 Persistent Storage - JSON-based device and configuration management
- 📊 Metrics & Monitoring - Real-time FPS, status, and performance data
Quick Start
Option 1: Docker (Recommended)
# Start server
docker-compose up -d
# View logs
docker-compose logs -f
# Stop server
docker-compose down
Server runs on: http://localhost:8080
Option 2: Python
# Create virtual environment
python -m venv venv
# Activate
source venv/bin/activate # Linux/Mac
venv\Scripts\activate # Windows
# Install dependencies
pip install .
# Set PYTHONPATH
export PYTHONPATH=$(pwd)/src # Linux/Mac
set PYTHONPATH=%CD%\src # Windows
# Run server
uvicorn ledgrab.main:app --host 0.0.0.0 --port 8080
Installation
Requirements
- Python 3.11+ (for Python installation)
- Docker & Docker Compose (for Docker installation)
- WLED device on your network
See ../INSTALLATION.md for comprehensive installation guide.
Configuration
Configuration File
Edit config/default_config.yaml:
server:
host: "0.0.0.0"
port: 8080
log_level: "INFO"
processing:
default_fps: 30 # Target frames per second
max_fps: 60 # Maximum allowed FPS
border_width: 10 # Pixels to sample from edge
wled:
timeout: 5 # Connection timeout (seconds)
retry_attempts: 3 # Number of retries
storage:
devices_file: "data/devices.json"
logging:
format: "json"
file: "logs/ledgrab.log"
Environment Variables
# Server configuration
export LEDGRAB_SERVER__HOST="0.0.0.0"
export LEDGRAB_SERVER__PORT=8080
export LEDGRAB_SERVER__LOG_LEVEL="INFO"
# Processing configuration
export LEDGRAB_PROCESSING__DEFAULT_FPS=30
export LEDGRAB_PROCESSING__BORDER_WIDTH=10
# WLED configuration
export WLED_WLED__TIMEOUT=5
Usage
WLED Device Setup
Important: Configure your WLED device using the official WLED web interface before connecting it to this controller:
- Access WLED Interface: Open
http://[wled-ip]in your browser - Configure Device Settings:
- Set LED count and type
- Configure brightness, color order, and power limits
- Set up segments if needed
- Configure effects and presets
This controller only sends pixel color data - it does not manage WLED settings like brightness, effects, or segments. All WLED device configuration should be done through the official WLED interface.
API Documentation
- Web UI: http://localhost:8080 (recommended for device management)
- Swagger UI: http://localhost:8080/docs
- ReDoc: http://localhost:8080/redoc
Quick Example
# 1. Add device
curl -X POST http://localhost:8080/api/v1/devices \
-H "Content-Type: application/json" \
-d '{"name":"Living Room","url":"http://192.168.1.100","led_count":150}'
# 2. Start processing
curl -X POST http://localhost:8080/api/v1/devices/{device_id}/start
# 3. Check status
curl http://localhost:8080/api/v1/devices/{device_id}/state
Testing
# Run all tests
pytest
# Run with coverage
pytest --cov=ledgrab --cov-report=html
# Run specific test
pytest tests/test_screen_capture.py -v
Development
Project Structure
src/ledgrab/
├── main.py # FastAPI application
├── config.py # Configuration
├── api/ # API routes
├── core/ # Core functionality
│ ├── screen_capture.py
│ ├── wled_client.py
│ ├── calibration.py
│ └── processor_manager.py
├── storage/ # Data persistence
└── utils/ # Utilities
Code Quality
# Format code
black src/ tests/
# Lint code
ruff check src/ tests/
License
MIT - see ../LICENSE