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PlaybackAPI_WebSocket.md 8.0KB

Web Socket Playback Information API (1.0.0)

Google Play Music Desktop Player provides an interface for external applications to determine the currently played song and playback status.

This interface is provided through a locally hosted Web Socket. In a standard release this WebSocket is hosted on port 5672. Any site or application should be able to connect to ws://localhost:5672 and use the API.

Message Format

All messages are sent from the Web Socket Server in the following format

{
  "channel": "channel_name",
  "payload": { ...data }
}

Channels

API_VERSION

Data recieved in the API_VERSION channel will have a payload in the format

"payload": String

The String will be a semver compliant version string for the WebSocketAPI. You should use this to determine if your app is designed to handle the current API syntax.

*As per semver any breaking change will result in a MAJOR version bump to the API but NOT to the app*

PlayState

Data received in the playState channel will have a payload in the format

"payload": Boolean

The Boolean value will be true if a song is currently playing, and false if a song is currently paused or stopped.

Track

Data received in the track channel will have a payload in the format

"payload": {
  "title": "Song Title",
  "artist": "Song Artist",
  "album": "Song Album",
  "albumArt": "URL pointing to the Album Art"
}

This data is sent every time the currently playing song changes. It is important to note that this channel will still be sent even if the song changes while the player is paused

Lyrics

Data received in the lyrics channel will have a payload in the format

"payload": "String of song lyrics here"

This data is sent every time the currently playing song changes. It is important to note that this channel will still be sent even if the song changes while the player is paused.
Also important to note that when the song first changes this channel will be sent with a “null” value. Once we have determined the lyrics for the new song, the lyrics will then be sent down this channel. You must therefore handle that brief period of time where lyrics is null.

Time

Data received in the time channel will have a payload in the format

"payload": {
  "current": Number,
  "total": Number
}

The current value is the time progressed through the current song in milliseconds.
The total value is the total time in milliseconds available to play in the current song.

This channel is sent on average every 100 - 200 milliseconds. You will receive a lot of data.

Rating

This data is sent when the song first starts playing and when the user changes his rating / rates a song.

Data received in the rating channel will have a payload in the format

"payload": {
  "liked": Boolean,
  "disliked": Boolean
}

Shuffle

Data received in the shuffle channel with have a payload in the format

"payload": "ALL_SHUFFLE"

Possible shuffle values can be found here

Repeat

Data received in the repeat channel will have a payload in the format

"payload": "LIST_REPEAT"

Possible repeat values can be found here

Playlists

Data received in the playlists channel will have a payload in the format

"payload": [ // 0 -> Many playlists
  {
    "id": String,      // You can assume this be be unique
    "name": String,    // The user defined name of the playlist
    "tracks": [ // 0 -> Many tracks
      {
        "id": String,  // Unique ID for this song
        "index": Number, // The index position (starting at 1) of the track in the playlist
        "title": String,
        "artist": String,
        "album": String,
        "albumArt": String,
        "duration": Number, // Duration of song in milliseconds
        "playCount": Number // Number of times the user has played this song
      }
    ]
  }
]

Queue

Data received in the queue channel will have a payload in the format

"payload": [ // 0 -> Many tracks
  {
    "id": String,             // Unique ID for this song
    "index": Number,          // The index position (starting at 1) of the track in the queue
    "title": String,
    "artist": String,
    "album": String,
    "albumArt": String,       // URL to the albumArt for this song
    "duration": Number,       // Duration of song in milliseconds
    "playCount": Number,      // Number of times the user has ever played the song
  }
]

Search-Results

Data received in the search-results channel will have a payload in the format

{
  "searchText": String,   // The text the user searched for to get these results
  "albums": [ // 0 -> Many albums
    {
      "id": String,           // Unique ID for this album
      "name": String,         // The name of the album
      "artist": String,       // The name of the artist for the album
      "albumArt": String,     // URL to the albumArt for this album
    }
  ]
  "artists": [ // 0 -> Many artists
    {
      "id": String,           // Unique ID for this artist
      "name": String,         // The name of the artist
      "image": String,        // URL to an image of this artist
    }
  ]
  "tracks": [ // 0 -> Many tracks
    {
      "id": String,             // Unique ID for this song
      "index": Number,          // The index position (starting at 1) of the track in the object that is storing a collection of tracks E.g. A Playlist
      "title": String,
      "artist": String,
      "album": String,
      "albumArt": String,       // URL to the albumArt for this song
      "duration": Number,       // Duration of song in milliseconds
      "playCount": Number,      // Number of times the user has ever played the song
    }
  ]
}

Controlling the application

Be Polite

If your app is going to be using the controller detailed below you must inform the user that you are now controlling the app. This is done by sending a message to WebSocket with a stringified JSON object in the form.

{
  "namespace": "connect",
  "method": "connect",
  "arguments": ["Name of Device / App"]
}

This command will trigger a response

{
  "channel": "connect",
  "payload": "CODE_REQUIRED"
}

A UI will popup in GPMDP containing a 4 digit code. You must instruct your user to provide this 4 digit code to you and you must then send it in the following form

{
  "namespace": "connect",
  "method": "connect",
  "arguments": ["Name of Device / App", "0000"]
}

If the code is incorrect the CODE_REQUIRED message will be sent to you again. If it is correct however you will receive a permanent authorization code in the following form

{
  "channel": "connect",
  "payload": "RANDOM_STRING_OF_CHARS_HERE"
}

As soon as you receive that message (and whenever you want to connect to the WebSocketAPI) you must simply send one message in the form.

{
  "namespace": "connect",
  "method": "connect",
  "arguments": ["Name of Device / App", "RANDOM_STRING_OF_CHARS_HERE"]
}

All Powerful Controller

You can use ANY method from the

All you need to do is send a message to the WebSocket with a stringified JSON object in the form.

{
  "namespace": "playback",
  "method": "setCurrentTime",
  "arguments": [10000]
}

Return Values

If the method has a return value you want to fetch you need to pass a requestID property to the WebSocket like so.

{
  "namespace": "playback",
  "method": "getCurrentTime",
  "requestID": 1
}

You will recieve a response in the following form

{
  "namespace": "result",
  "type": "return", // This will be "error" if the method threw an error
  "value": 10000, // This will be the error object if the method threw an error
  "requestID": 1
}