cto-radio

Warning

Experimental — not for public consumption. This is a personal, single-listener hobby stream. It is extremely unstable: it drops, stutters, and goes silent without notice, and any public endpoint may vanish at any time. Don't depend on it, don't share the listen link, and don't treat any URL here as a service. Read it as a reference build, not a station you can tune into.

Turn a headless box into an always-on Spotify Connect device that streams whatever it plays to a webpage you can open anywhere.

Two problems this solves:

1. Cold start. Spotify can only start playback on a device that's already open. Close the app on your phone and the device vanishes — there's nothing to "press play" on. A headless go-librespot instance is a device that never sleeps, so you can start playback any time, from anything (the Spotify API, a script, your phone), with no app open first.
2. Hearing it. A headless server has no speakers. So the audio is piped out as a live HTTP stream you tune into from a browser, phone, or any media player.

go-librespot ──▶ FIFO (raw PCM) ──▶ ffmpeg ──▶ Icecast ──▶ http://you:8000/stream-<token>.mp3
                                                                        ▲
                                                                you, anywhere

No PulseAudio/PipeWire needed — audio goes straight through a named pipe.

Pieces

File	What it is
config.yml.example	go-librespot config — device name, bitrate, pipe output, headless OAuth
icecast.xml.example	Icecast config — passwords, the mount, a silence fallback
stream.env.example	source password + mount token for the ffmpeg service
listen.html	a dark, self-reconnecting player page — shows cover art, title and progress
cto-now.sh	polls go-librespot and writes now.json into the webroot for the player
cto-now.service	--user service that runs the now-playing feeder
systemd/*.service	four --user services that keep the whole chain alive

Setup

Assumes Linux with ffmpeg and icecast installed, and the go-librespot binary at /usr/local/bin/go-librespot.

1. go-librespot config + first login

mkdir -p ~/.config/go-librespot ~/.local/share/go-librespot
cp config.yml.example ~/.config/go-librespot/config.yml
# edit it: set your username path, device_name, bitrate
go-librespot         # prints an authorize URL

Open the URL in a browser logged into your Spotify account, approve, and the redirect to 127.0.0.1 completes the login. Credentials cache to ~/.config/go-librespot/state.json — you only do this once. (Spotify Premium required.)

2. Icecast

sudo cp icecast.xml.example /etc/icecast.xml
# edit: set source/admin passwords, your hostname/IP, and an unguessable mount token
# generate a silence fallback so the mount stays alive during pauses:
ffmpeg -f lavfi -i anullsrc=r=44100:cl=stereo -t 5 -b:a 128k silence.mp3
sudo cp silence.mp3 /usr/share/icecast/web/silence.mp3
sudo systemctl enable --now icecast

3. Player page — drop listen.html in the Icecast webroot and point SRC at your mount:

sudo cp listen.html /usr/share/icecast/web/listen.html
# edit the SRC constant in it to /stream-<your-token>.mp3

4. The services

mkdir -p ~/.config/cto-stream
cp stream.env.example ~/.config/cto-stream/stream.env   # set SRC + LIS, then: chmod 600
chmod 600 ~/.config/cto-stream/stream.env

cp systemd/*.service ~/.config/systemd/user/
loginctl enable-linger "$USER"      # run without an active login
systemctl --user daemon-reload
systemctl --user enable --now cto-fifo cto-pipe-keeper go-librespot cto-stream

Now your box shows up in Spotify as a device. Play to it from anywhere, and open http://YOUR_IP:8000/listen.html to hear it.

Listening

The listen.html page is fine in a pinch, but mobile browsers are the worst case for a live stream — they buffer poorly and won't auto-resume after a stall. For a steady listen, use a real audio app and point it at the raw mount (http://YOUR_IP:8000/stream-<token>.mp3):

• VLC (any platform) — most bulletproof. New stream → paste the URL.
• Transistor (Android, F-Droid) — minimal, purpose-built for one custom radio URL.

Some apps choke on a bare .mp3 and want a playlist file. Drop a .pls (and/or .m3u) in the Icecast webroot — it carries the station name and the stream URL, so the app shows a proper named station instead of nothing:

STREAM="http://YOUR_IP:8000/stream-<token>.mp3"

# .pls — most widely accepted by radio apps
printf '[playlist]\nNumberOfEntries=1\nFile1=%s\nTitle1=My box\nLength1=-1\nVersion=2\n' "$STREAM" \
  | sudo tee /usr/share/icecast/web/station.pls >/dev/null

# .m3u — alternative
printf '#EXTM3U\n#EXTINF:-1,My box\n%s\n' "$STREAM" \
  | sudo tee /usr/share/icecast/web/station.m3u >/dev/null

Then add http://YOUR_IP:8000/station.pls in the app. (.pls plays cleanly in VLC; if an app prefers the other, .m3u is right there.)

How it holds together

• The FIFO keeper (cto-pipe-keeper) holds both ends of the named pipe open. Without it, when ffmpeg or go-librespot restarts the other side gets an EOF or SIGPIPE and dies. The keeper opens the FIFO read-write and just sits there — it never reads, so it steals no audio, it only keeps the pipe from ever signalling end-of-stream.
• source-timeout is set high (2h) so Icecast doesn't drop the source during a long pause. The silence.mp3 fallback covers brief gaps so the mount URL never 404s.
• The mount token is the secret. The stream is at /stream-<random>.mp3; the unguessable path is what keeps it private while staying trivial to open in any player (no auth dialog). Rotate it by changing the mount name.
• The player page reconnects itself — a watchdog reopens the stream only if playback genuinely stalls for 15s, and it resumes when you unlock your phone. It deliberately does not reconnect on every transient stalled event (that just causes endless rebuffering).

Notes

• High latency between your server and your phone? Drop the ffmpeg bitrate (-b:a) to 128k — plenty for casual listening and far kinder to thin mobile buffers.
• go-librespot also stays LAN-discoverable (zeroconf), so a phone on the same network can hand off to it directly.

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Built one evening, for the joy of it.