asteroid/docs/STREAM-CONTROL.org

Stream Queue Control System

• Overview
• How It Works
• API Endpoints (Admin Only)
  • Get Current Queue
  • Add Track to Queue
  • Remove Track from Queue
  • Clear Queue
  • Add Playlist to Queue
  • Reorder Queue
• Usage Examples
  • Building a Stream Queue
  • Managing the Queue
• Lisp Functions
• File Locations
• How Liquidsoap Reads Updates
• Stream History
• Future Enhancements
• Troubleshooting
  • Queue changes not taking effect
  • Empty queue falls back to random
  • Playlist file not updating
• Integration with Admin Interface

Overview

The stream queue control system allows administrators to manage what plays on the main Asteroid Radio broadcast stream. Instead of random playback from the music library, you can now curate the exact order of tracks.

How It Works

1. Stream Queue - An ordered list of track IDs maintained in memory
2. M3U Generation - The queue is converted to a stream-queue.m3u file
3. Liquidsoap Integration - Liquidsoap reads the M3U file and reloads it every 60 seconds
4. Fallback - If the queue is empty, Liquidsoap falls back to random directory playback

API Endpoints (Admin Only)

All endpoints require admin authentication.

Get Current Queue

GET /api/asteroid/stream/queue

Returns the current stream queue with track details.

Add Track to Queue

POST /api/asteroid/stream/queue/add
Parameters:
  - track_id: ID of track to add
  - position: "end" (default) or "next"

Adds a track to the end of the queue or as the next track to play.

Remove Track from Queue

POST /api/asteroid/stream/queue/remove
Parameters:
  - track_id: ID of track to remove

Removes a specific track from the queue.

Clear Queue

POST /api/asteroid/stream/queue/clear

Clears the entire queue (will fall back to random playback).

Add Playlist to Queue

POST /api/asteroid/stream/queue/add-playlist
Parameters:
  - playlist_id: ID of playlist to add

Adds all tracks from a user playlist to the stream queue.

Reorder Queue

POST /api/asteroid/stream/queue/reorder
Parameters:
  - track_ids: Comma-separated list of track IDs in desired order

Completely reorders the queue with a new track order.

Usage Examples

Building a Stream Queue

# Add a specific track to the end
curl -X POST http://localhost:8080/api/asteroid/stream/queue/add \
  -d "track-id=42" \
  -H "Cookie: radiance-session=..."

# Add a track to play next
curl -X POST http://localhost:8080/api/asteroid/stream/queue/add \
  -d "track-id=43&position=next" \
  -H "Cookie: radiance-session=..."

# Add an entire playlist
curl -X POST http://localhost:8080/api/asteroid/stream/queue/add-playlist \
  -d "playlist-id=5" \
  -H "Cookie: radiance-session=..."

Managing the Queue

# View current queue
curl http://localhost:8080/api/asteroid/stream/queue \
  -H "Cookie: radiance-session=..."

# Remove a track
curl -X POST http://localhost:8080/api/asteroid/stream/queue/remove \
  -d "track-id=42" \
  -H "Cookie: radiance-session=..."

# Clear everything
curl -X POST http://localhost:8080/api/asteroid/stream/queue/clear \
  -H "Cookie: radiance-session=..."

Lisp Functions

If you're working directly in the Lisp REPL:

;; Add tracks to queue
(add-to-stream-queue 42 :end)
(add-to-stream-queue 43 :next)

;; View queue
(get-stream-queue)

;; Add a playlist
(add-playlist-to-stream-queue 5)

;; Remove a track
(remove-from-stream-queue 42)

;; Clear queue
(clear-stream-queue)

;; Reorder queue
(reorder-stream-queue '(43 44 45 46))

;; Build smart queues
(build-smart-queue "electronic" 20)
(build-queue-from-artist "Nine Inch Nails" 15)

;; Manually regenerate playlist file
(regenerate-stream-playlist)

File Locations

• Stream Queue File: /home/glenn/Projects/Code/asteroid/stream-queue.m3u
• Docker Mount: /app/stream-queue.m3u (inside Liquidsoap container)
• Liquidsoap Config: docker/asteroid-radio-docker.liq

How Liquidsoap Reads Updates

The Liquidsoap configuration reloads the playlist file every 60 seconds:

radio = playlist.safe(
  mode="normal",
  reload=60,
  "/app/stream-queue.m3u"
)

This means changes to the queue will take effect within 1 minute.

Stream History

The system also tracks recently played tracks:

;; Get last 10 played tracks
(get-stream-history 10)

;; Add to history (usually automatic)
(add-to-stream-history 42)

Future Enhancements

• Web UI for queue management (drag-and-drop reordering)
• Telnet integration for real-time skip/next commands
• Scheduled programming (time-based queue switching)
• Auto-queue filling (automatically add tracks when queue runs low)
• Genre-based smart queues
• Listener request system

Troubleshooting

Queue changes not taking effect

• Wait up to 60 seconds for Liquidsoap to reload
• Check that stream-queue.m3u was generated correctly
• Verify Docker volume mount is working: docker exec asteroid-liquidsoap ls -la /app/stream-queue.m3u
• Check Liquidsoap logs: docker logs asteroid-liquidsoap

Empty queue falls back to random

This is expected behavior. The system will play random tracks from the music library when the queue is empty to ensure continuous streaming.

Playlist file not updating

• Ensure Asteroid server has write permissions to the project directory
• Check that regenerate-stream-playlist is being called after queue modifications
• Verify the file exists: ls -la stream-queue.m3u

Integration with Admin Interface

The stream control system is designed to be integrated into the admin web interface. Future work will add:

• Visual queue editor with drag-and-drop
• "Add to Stream Queue" buttons on track listings
• "Queue Playlist" buttons on playlist pages
• Real-time queue display showing what's currently playing
• Skip/Next controls for immediate playback changes (via Telnet)