Raspberry Pi Internet Radio

Internet radio controlled with a web-based front-end or a REST api.

Setup

All components are implemented as docker containers. To start, install Docker and docker-compose and run

docker-compose up

This will start all containers and a web server will be accessible at port 8080.

API reference

The radio API is used to control the radio and to manage stations. The endpoints are:

Play

POST /api/play

Parameters:

Parameter	Value
url (optional)	The station URL to play
station_id (optional)	The id of the station to play

Response:

A status message. For example:

{
   "volume":100,
   "bitrate":"92",
   "state":"PLAYING",
   "name":"DR P6 BEAT",
   "url":"http://live-icy.gss.dr.dk/A/A29H.mp3.m3u",
   "title":"Senest spillet: Yuk Foo | Wolf Alice"
}

The state can either be PLAYING or STOPPED.

Stop

POST /api/stop

Response:

A status message.

Volume

POST /api/volume

Parameters:

Parameter	Value
vol	The volume (between 0 and 100)

Response:

A status message.

Station list

GET /api/stations

Parameters:

Parameter	Value
is_favorite (optional)	Boolean value specifying whether to only receive favorite stations

Response:

An array of stations:

[
   {
      "id":2,
      "url":"http://live-icy.gss.dr.dk/A/A03H.mp3.m3u",
      "is_favorite":false,
      "name":"DR P1"
   },
   {
      "id":3,
      "url":"http://live-icy.gss.dr.dk/A/A04H.mp3.m3u",
      "is_favorite":false,
      "name":"DR P2"
   },
   {
      "id":5,
      "url":"http://live-icy.gss.dr.dk/A/A10H.mp3.m3u",
      "is_favorite":false,
      "name":"DR P4 Nordjylland"
   }
]

Station info

GET /api/stations/[station_id]

Response:

A station object:

{
   "id":2,
   "url":"http://live-icy.gss.dr.dk/A/A03H.mp3.m3u",
   "is_favorite":false,
   "name":"DR P1"
}

Station modification

Stations can be created with POST requests:

POST /api/stations/

With data containing a new station object.

Stations can be updated with PUT requests:

PUT /api/stations/[station_id]

and deleted with DELETE requests:

DELETE /api/stations/[station_id]

Architecture

The entire project is structured in five Docker containers: app-server (front-end), api-server, web-radio (the radio component), db (PostgreSQL), and nginx.

The front-end is styled with Materialize and implemented using Rivets.js and Socket.io. The web-servers (front-end and API) are implemented with Flask running behind Gunicorn and nginx. The web radio is implemented using Music Player Daemon. All communication between containers is done using GRPC.

General Setup Tips

To improve the analogue audio output, add the following line to /boot/config.txt

audio_pwm_mode=2

(via this forum post)