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WebSocket APIs

Introduction​

The most used API transport in Volumio2 is its Websockets API as it allows almost real time communication with multiple clients. Volumio's WebUI gets and sends data (almost) exclusively via WS. Volumio's WS layer is powered by Socket.io. The WebSocket API interface is located at: https://github.com/volumio/Volumio2/blob/master/app/plugins/user_interfaces/websocket/index.js

Scenarios​

Websocket communication in Volumio is identifiable in the most basic server/client architecture. The Server is Volumio itself (aka the host where Volumio is running), the client can be one or more WebUIs or other consumers (Apps and so on). In some cases, Volumio hosts can also act as client, to communicate with other hosts on the same network.

Events​

Socket.io allows to invoke events triggered by other events, emit and receive communications (on its most basic implementation). As an example, defining which event should be invoked on a client connection looks like:

self.libSocketIO.on('connection', function (connWebSocket) {
  // use connWebSocket here
});

This way, we can define what event should be triggered when a particular message is received:

connWebSocket.on('bringmepizza', function () {
  givehimpizza();
});

Typically, every message we send or receive to Volumio's Backend will have this structure:

io.emit('message','data');

Where message can be for example "play" and data can be the song number. A good policy for sending data on emits is to configure them as objects: they're easier to parse and easily extendable. So our message can be:

io.emit('addToPlaylist', {"name": "Music", "service": "mpd", "uri": "music-library/..."});

Events Documentation​

Basic Playback Commands​

**Play:** play
**Pause:** pause
**Stop:** stop
**Previous:** prev
**Next:** next
**Seek** seek N (N is the time in seconds that the playback will keep)
**Random** setRandom({"value":true|false})
**repeat** setRepeat({"value":true|false})

Get Player State​

getState

Reply:

pushState
{
  "status": "stop",
  "position": 0,
  "title": "Matilda Mother",
  "artist": "Pink Floyd",
  "album": "The Piper At The Gates Of Dawn",
  "albumart": "/albumart?web=Pink%20Floyd/The%20Piper%20At%20The%20Gates%20Of%20Dawn/extralarge&path=%2FNAS%2FHi_Res_Music%2FPINK%20FLOYD%20Discovery%20Studio%20Album%20Box%20Set%20(2011)%20FLAC%2F1967%20The%20Piper%20At%20The%20Gates%20Of%20Dawn",
  "uri": "mnt/NAS/Hi_Res_Music/PINK FLOYD Discovery Studio Album Box Set (2011) FLAC/1967 The Piper At The Gates Of Dawn/03 - Matilda Mother.flac",
  "trackType": "flac",
  "seek": 0,
  "duration": 189,
  "random": false,
  "repeat": false,
  "repeatSingle": false,
  "volume": 39,
  "mute": false,
  "stream": false,
  "updatedb": false,
  "volatile": false,
  "service": "mpd"
}

Where

  • status is the status of the player
  • position is the position in the play queue of current playing track (if any)
  • title is the item's title
  • artist is the item's artist
  • album is the item's album
  • albumart the URL of AlbumArt (via last.fm APIs)
  • uri it's the track's unique uri
  • trackType The track's type: e.g. mp3, flac, spotify etc
  • seek is the item's current elapsed time
  • duration is the item's duration, if any
  • random if true, random mode is enabled
  • repeat if true, repeat mode is enabled
  • repeatSingle if true, repeat single mode is enabled (song is replayed in a cycle)
  • volume current Volume
  • mute if true, Volumio is muted
  • stream if true, Volumio is playing a stream (webradio)
  • updatedb if true, Volumio is updating its internal music database
  • volatile if true, Volumio is in Volatile mode (analog input)
  • samplerate current samplerate
  • bitdepth bitdepth
  • channels mono or stereo
  • service current playback service (mpd, spop...)
search {value:'query'}

Where query is my search query. (note that for using live search, DO NOT send queries with less than 3 characters, they will dramatically slow search operations).

Volume​

Set to percentage, raise or lower, mute or unmute.

Message: volume

Data:

  • numeric value between 0 and 100
  • mute
  • umute
  • +
  • -

Example

io.emit('volume', 90);
io.emit('volume', '+');

Mute​

Message: mute

Example

io.emit('mute', '');

Unmute​

Message: unmute

Example

io.emit('unmute', '');

Multiroom​

getMultiRoomDevices

Retrieves all devices connected to the same network. Input: None

Output (through pushMultiRoomDevices socket.io event):

   {
      "misc": {"debug": true},
      "list": [
         {
                "id":"uuid",
                "host":"",
                "name":"",
                "isSelf":true|false,
                "state": {
                    "status": "",
                    "volume": 0,
                    "mute": true|false,
                    "artist": "",
                    "track": ""
                },
                                {
                "id":"uuid",
                "host":"",
                "name":"",
                "isSelf":true|false,
                "state": {
                    "status": "",
                    "volume": 0,
                    "mute": true|false,
                    "artist": "",
                    "track": ""
                }
      ]
   }

Browse Music Library​

browseLibrary objBrowseParameters

Where objBrowseParameters are the parameters we want to dig into. This returns the desired level in the music library along with navigation and pagination informations.

{
  navigation: {
    prev: {
      uri: ''
    },
    list: [
      {service: 'mpd', type: 'song',  title: 'track a', artist: 'artist a', album: 'album', icon: 'music' uri: 'uri'},
      {type: 'folder',  title: 'folder a', icon: 'folder-open-o' uri: 'uri'},
      {type: 'folder',  title: 'folder b', albumart: '//ip/image' uri: 'uri2'},
      {type: 'playlist',  title: 'playlist', icon: 'bars' uri: 'uri4'}
    ]
  }
}

The browsable items can be;

  • Track
  • Folder (can also be a category)
  • Playlist

Their parameters are:

  • Type: track, folder, category
  • Title: If this is a song: title, if folder or category is their name.
  • Artist and Album: used only if the type is song
  • Icon or image: Select the icon to display (naming of Font-Awesome ) , or image (URL served by Volumio Backend or external service)
  • Uri: Uri

Get Music Library Available filters​

getBrowseFilters

This returns available filters (browse by)

{name:'Genres by Name', index: 'index:Genres by Name'},
{name:'Artists by Name', index: 'index:Artists by Name'},
{name:'Albums by Name', index: 'index:Albums by Name'},
{name:'Albums by Artist', index: 'index:Albums by Artist'},
{name:'Tracks by Name', index: 'index:Tracks by Name'}

Get Music Sources​

getBrowseSources

This returns a list of available Music Sources

{name:'USB', uri: 'usb'},
{name:'NAS', uri: 'nas'},
{name:'Web Radio', uri: 'web-radio'},
{name:'Spotify', uri: 'spotify'}

Custom Browse Source​

This can be useful when creating a new plugin, to inject custom views in the browse sources panel, along with top-level custom actions.

{
  "name": "Custom Source",
  "pluginName": "streaming_controller",
  "pluginType": "music_service",
  "uri": "stream",
  "info": "Additional info",
  "menuItems": [
    {
      "name": "play",
      "socketCall": {
        "emit": "callMethod",
        "payload": {
          "endpoint": "music_service/streaming_controller",
          "method": "launchStream",
          "data": ""
        }
      }
    },
    {
      "name": "rip",
      "socketCall": {
        "emit": "callMethod",
        "payload": {
          "endpoint": "music_service/streaming_controller",
          "method": "updateStream",
          "data": ""
        }
      }
    },
    {
      "name": "eject",
      "socketCall": {
        "emit": "callMethod",
        "payload": {
          "endpoint": "music_service/streaming_controller",
          "method": "refreshStream",
          "data": ""
        }
      }
    }
  ]}

Play Queue Controls​

Get Current Play Queue​

getQueue

Response:

pushQueue
[ { uri: 'http://yp.shoutcast.com/sbin/tunein-station.m3u?id=830692',
    title: 'ANTENA1 - 94 7 FM',
    service: 'webradio',
    name: 'ANTENA1 - 94 7 FM',
    albumart: '/albumart',
    samplerate: '',
    bitdepth: '',
    channels: 0,
    trackType: 'webradio' },
  { uri: 'mnt/NAS/FLAC/Muse - Black Holes And Revelations - FLAC - HellraiserRG/02 - Starlight.flac',
    service: 'mpd',
    name: 'Starlight',
    artist: 'Muse',
    album: 'Black Holes And Revelations',
    type: 'track',
    tracknumber: 0,
    albumart: '/albumart?web=Muse/Black%20Holes%20And%20Revelations/extralarge&path=%2FNAS%2FFLAC%2FMuse%20-%20Black%20Holes%20And%20Revelations%20-%20FLAC%20-%20HellraiserRG',
    duration: 240,
    samplerate: '44.1 KHz',
    bitdepth: '16 bit',
    trackType: 'flac',
    channels: 2 }]

Remove Item from queue​

removeFromQueue {value: N}

where N is the track number in the queue, 0 for the first, 9 for the tenth and so on

Response:

pushQueue

Add Item to Queue​

addToQueue {uri:'uri'}

where uri is the uri of the item we want to add

Move a queue item​

moveQueue {from:N,to:N2}

Where N is the track number we want to move, and N2 is its new position

If we want to add an individual track from a .cue file:

addPlayCue {uri:'uriofsong',number:3}

Favourites handling​

Available functionality:

  • addToFavourites
  • removeFromFavourites

addToFavourites​

This method adds a song to the favourites

Input:

   {
    "uri":"my_uri/...",
    "title":"my song",
    "service":"my_service"
   }

Output:

   {
    "success":true|false
    "reason":"failure details"
   }

The reason field is set only if success is false

removeFromFavourites​

This method removes all occurrences of a song from the favourites

Input:

   {
    "uri":"my_uri/...",
    "service":"my_service"
   }

Output:

   {
    "success":true|false
    "reason":"failure details"
   }

The reason field is set only if success is false

Playlist handling​

Available functionality:

  • createPlaylist
  • deletePlaylist
  • listPlaylist
  • addToPlaylist
  • removeFromPlaylist
  • playPlaylist
  • enqueue

createPlaylist​

This method creates a new playlist

Input:

   {
    "name":"myplaylist"
   }

Output:

   {
    "success":true|false
    "reason":"failure details"
   }

The reason field is set only if success is false

deletePlaylist​

This method deletes a playlist

Input:

   {
    "name":"myplaylist"
   }

Output:

   {
    "success":true|false
    "reason":"failure details"
   }

The reason field is set only if success is false

listPlaylist​

This method lists all playlists in the system

Input: None

Output (through event pushListPlaylist):

   [
     "playlistA",
     "playlistB",
     ...
   ]

The reason field is set only if success is false

addToPlaylist​

This method adds a song to an existing playlist

Input:

   {
    "name":"my playlist",
    "service":"mpd",
    "uri":"USB/..."
   }

Output:

   {
    "success":true|false
    "reason":"failure details"
   }

The reason field is set only if success is false

removeFromPlaylist​

This method removes all occurrences of a song from an existing playlist

Input:

   {
    "name":"my playlist",
    "uri":"USB/..."
   }

Output:

   {
    "success":true|false
    "reason":"failure details"
   }

The reason field is set only if success is false

playPlaylist​

This method clears the queue, adds the playlist and play

Input:

   {
    "name":"my playlist"
   }

Output:

   {
    "success":true|false
    "reason":"failure details"
   }

The reason field is set only if success is false

enqueue​

This method enqueue all songs of a playlist

Input:

   {
    "name":"my playlist"
   }

Output:

   {
    "success":true|false
    "reason":"failure details"
   }

The reason field is set only if success is false

CallMethod on Plugin​

Each method of a plugin can be execute through a websocket call. As of now there's no ACL or any security feature but thi s will change in the future. To execute a method the following socket.io command shall be issued:

callMethod

The payload shall be a json with the following structure:

   {
    "endpoint":"category/name",
    "method":"methodName",
    "data": {}
   }

where:

  • endpoint is a string used to target the plugin. Its structure is a linux path like string containing the plugin category, a slash and the plugin name. An example: endpoint:'music_service/spop'.
  • method is a string containing the name of the method to be executed.
  • data is a complex value (can be a string or a Json) and is passed as is to the method.

IMPORTANT: There should be no "-" in this call, due to FE parsing method (it converts / to -). So plugins and functions should not contain "-".

Once the method returns, the result is pushed back to the client with the event 'pushMethod'.

Miscellaneous​

Sleep & Alarm Clock​

getSleep

Triggers :

pushSleep {enabled:true|false, time:hh:mm:}

To set sleep mode:

setSleep {enabled:true|false, time:hh:mm:}
getAlarms

Triggers:

pushAlarms {[{id:1,enabled:true, time:hh:mm, playlist:uriplaylist},{id:2,enabled:true, time:hh:mm, playlist:uriplaylist}]}

To add a new alarm:

addAlarm {time:hh:mm, playlist:uriplaylist}

When a new Playlist gets added, the Values enabled:true and id (as progressive numbering) are added by default by the Backend.

To edit an alarm:

setAlarm {id:1,enabled:true, time:hh:mm, playlist:uriplaylist}

Those values will replace the values of the correspondent playlist id.

To remove an alarm:

removeAlarm {id:3}