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Javascript-SDK

Overview​

Our JavaScript SDK powers music playback for websites. This SDK does not have all the features of our native SDKs, but it does support basic streaming and simulcast playback. And it’s framework agnostic, so it works with React, Vue, Angular, and other web app tools.

The library is published via NPM as feed-media-audio-player. The SDK makes use of the HTML Audio element, and has no external dependencies.

Introduction​

The Feed Media SDK for Javascript allows you to play DMCA compliant radio within your browser.. This library includes a Feed.Player class, which offers a simple interface starting and stopping audio playback, and Feed.PlayerView, which offers a simple way to render a music player in HTML.

This javascript library makes use of the Audio element and works with desktop browsers that support it: Edge 80+, Firefox 76+, Chrome 79+, and Safari 11.1+.

warning

We do NOT support mobile web browsers using our Javascript SDK. While the Javascript SDK may have some success on mobile web browsers, we do not officially support these mobile web integrations. To create the best user experience, we recommend understanding these limitations prior to developing on mobile web. In general, Feed.fm best practices discourage the use of our Javascript SDK on mobile web to ensure the applications you develop are optimized for the best possible user experience. We recommend building native mobile applications which can utilize our iOS SDK and Android SDK.

This library will work with the default demo credentials built into it, but you will need to get a set of production credentials from your contact at Feed.fm.

For bug reporting or questions, please send an email to support@feed.fm.

Installation​

Via npm​

Install via npm:

npm install feed-media-audio-player

Use <script> tag​

The dist/feed-media-audio-player.min.js file in this package is suitable for including directly in an HTML page. This is a self-executing function that exposes a Feed variable to your javascript. The file has no external dependencies.

CJS or Modules​

Alternatively, if you're using a bundler, add the following to your code:

var Feed = require('feed-media-audio-player');

or

import Feed from 'feed-media-audio-player';

Bundler will automatically pull in dependent libraries.

Basic music player with UI​

To create a simple player and work with the Player and PlayerView objects, create a web page with the following content (or start with this jsbin):

<div id="player-view-div">
  <div class='status'></div>
  <button class="play-button">play</button>
  <button class="pause-button">pause</button>
  <button class="skip-button">skip</button>
</div>

<script src="feed-media-audio-player.min.js"></script>
<script>
  var player = new Feed.Player('demo', 'demo');
  
  // Display all the events the player triggers
  player.on('all', function(event) {
    console.log('player triggered event \'' + event + '\' with arguments:', Array.prototype.splice.call(arguments, 1));
  });
  
  var playerView = new Feed.PlayerView('player-view-div', player);
  
  player.tune();
</script>

When the page is run, the user will be able to start and stop music playback, and skip songs. The control buttons enable and disable themselves based on the state of the player.

Working with Feed.Player​

The Feed.Player class retrieves music from the Feed.fm servers and sends them to the browser for playback. The methods on instances of this class are mostly asynchronous, and events (that can be subscribed to with simple on() and off() methods) indicate player activity.

The class requires a token and secret in order to create an instance of the player:

  var player = new Feed.Player('token', 'secret' /*, options */);

The final argument is optional and lets you specify some extra parameters for the player (fully documented here).

Construction of the Player instance kicks off communication with the feed.fm servers to determine what music is available to the client. The player should not be used until either a 'not-in-us' event or a 'stations' event is triggered, to indicate that no music is available to the user or to indicate which music stations can be tuned to.

The basic methods for use on the object are play(), pause(), stop() and skip(), which do what you might expect.

You can adjust and retrieve music volume via getVolume() and setVolume(X) (where X is 0..100) on the Player instance.

Due to auto-play restrictions on browsers, and especially Mobile Safari, the first call to play() on the player object must be made in a user-initiated event handler. If you don't want to immediately play music on the user event, you can call initializeAudio() in the event handler, and then play() at a later time. Repeated calls to initializeAudio() are fine.

The player emits named events that you can attach to in order to follow the state of the player. To follow an event, use the on(event, callback, context) method, and to stop following an event use the off(event) method. Event handling comes from the BackBone.js project. Some example usage:

  // simple callback
  player.on('play-completed', function() { console.log('a play completed!'); });

  // third argument sets 'this' for callback function
  player.on('play-started', handler.someFunction, handler);

  // passing 'all' as the event will cause all events to be sent to this callback
  player.on('all', function(event) { console.log('received: ', event); });

  // turn off all handlers for this event
  player.off('play-completed');

  // turn off a specific handler for this event
  player.off('play-started', handler.someFunction);

The player emits the following events:

  • music-unavailable - Feed.fm doesn't believe that the client is located in a region for which music is licensed for playback. When this event is emitted, you can assume the player will no longer function. This event is only emitted once, shortly after construction of the Player instance, so register for this event early!
  • stations - This event provides the list of stations available to the player, as provided by the server. It is triggered before any music starts, after the player has contacted feed.fm. See "Station and Play objects" below for details on what the station object looks like.
  • play-started - This is sent when playback of a specific song has started. Details of the song that has just started are passed as an argument and are described in "Station and Play objects" below.
  • play-paused - This is sent when playback of the current song is paused.
  • play-resumed - This is sent when playback of the current song is resumed after pausing.
  • play-stopped - This is sent when the 'stop()' method is called in Player
  • play-completed - This is sent when playback of the current song is complete or is aborted (due to a skip, for instance).
  • plays-exhausted - If there are no more songs that a user can listen to, this event is triggered.
  • skip-denied - If a call was made to skip() to skip the current song, but the server denied it (due to skip restrictions), then this event will be emitted.

In addition to responding to events, the current state of the player can be queried with getCurrentState(). That call will return one of the following strings:

  • playing - the player is currently playing a song
  • paused - the player is paused
  • idle - the player has no song actively playing or paused

Station and Play objects​

A station object looks like the following:

  {
    id: "276510",
    name: "90BPM",
    on_demand: 0,
    pre_gain: 11.32,
    options: {
      id: "90BPM"
    },
    last_updated: "2019-04-05T21:49:08.000Z"
  }

Some important points:

  • The station id will change between different sessions - and should not be used, for instance, to remember a user's favorite station. Instead, you should use the station's name or a value in the options object.
  • The options object can be any arbitrary JSON object that you provide to feed.fm. We suggest you use this for storing foreign keys or values that you wish to use to search for particular stations. Some examples: storing a 'genre' or your own 'id' or numeric BPM range.
  • last_updated refers to the last time the contents of a station with this name were updated.

A play object looks like the following:

{
  "id":"132459570",
  "station": {
    "id":"727",
    "name":"Pretty Lights Music"
  },
  "audio_file": {
    "id":"8707",
    "duration_in_seconds":349,
    "track": { 
      "id":"15226435",
      "title":"Starve the Ego, Feed the Soul"
    },
    "release": {
      "id":"1550367",
      "title":"Drink the Sea"
    },
    "artist": {
      "id":"1176632",
      "name":"The Glitch Mob"
    }
  }
}

Working with Feed.PlayerView​

Feed.PlayerView should be given the ID of an element in the page and a reference to a Feed.Player instance, and it will update child elements based on player events and listen to user clicks to tell the Feed.Player to pause/play/skip. Child elements are identified by their class name and are used as described below:

  • status - This is updated to display the song currently being played, or the name of the placement that we're streaming from. The 'formatPlay(play)' method can be overridden to change how the current song is formatted, and the 'formatPlacement(placement)' method can be overriden to change how the placement is formatted. Also, if there are errors or alerts that need to be displayed, those are placed here and an 'alert' class is added to this element. After displaying an alert, the status is automatically reverted back to the song or placement text after a few seconds.
  • elapsed - As a song is playing, the text of this element is updated with the elapsed playback time in the format '0:00'.
  • duration - When a song starts playing, the text of this element is set to the total duration of the song in the format '0:00'.
  • progress - While a song is playing the 'width' of this element is changed from 0% to 100%.
  • play-button - When clicked, this will start playback. This button may be disabled (for instance, when a song is already playing). The button is enabled by adding a 'button-enabled' class. The button is disabled by adding a 'button-disabled' class and setting the 'disabled' attribute to true.
  • pause-button - When clicked, this will pause playback. This button may be disabled (for instance, when a song is already paused). The button is enabled by adding a 'button-enabled' class. The button is disabled by adding a 'button-disabled' class and setting the 'disabled' attribute to true.
  • skip-button - When clicked, this will request a song skip. This button may be disabled (for instance, when a song may not be skipped). The button is enabled by adding a 'button-enabled' class. The button is disabled by adding a 'button-disabled' class and setting the 'disabled' attribute to true.

The sample jsbin has a function to display in the javascript console all the events that the player emits.

When creating your own player skin, most everything can be stylized without having to edit javascript. For most projects, you should be able to fully customize the player using only CSS rules that take into account the 'button-enabled' and 'button-disabled' classes, along with the state of the player that is attached as a class to the top level HTML element of the player.