media-player-controller/players/mpv.js

Spawn media player app and control playback

const noop = () => {};
var prevPosition;

module.exports =
{
	init: function()
	{
		prevPosition = null;

		this.command(['observe_property', 1, 'time-pos']);
		this.command(['observe_property', 2, 'volume']);
		this.command(['observe_property', 3, 'pause']);
		this.command(['observe_property', 4, 'duration']);
		this.command(['observe_property', 5, 'eof-reached']);
		this.command(['observe_property', 6, 'speed']);
		this.command(['observe_property', 7, 'media-title']);
	},

	_connectType: 'socket',

	_getSpawnArgs: function(opts)
	{
		var presetArgs = [
			`--input-ipc-server=${opts.ipcPath}`,
			opts.media
		];

		return [ ...opts.args, ...presetArgs ];
	},

	command: function(params, cb)
	{
		cb = cb || noop;
		var command = null;

		if(!this.writable)
			return cb(new Error('No writable IPC socket! Playback control disallowed'));

		if(!Array.isArray(params))
			return cb(new Error('No command parameters array!'));

		try { command = JSON.stringify({ command: params }); }
		catch(err) { return cb(err); }

		this._debug(command);
		this.write(command + '\n', cb);
	},

	play: function(cb)
	{
		cb = cb || noop;
		this.command(['set_property', 'pause', false], cb);
	},

	pause: function(cb)
	{
		cb = cb || noop;
		this.command(['set_property', 'pause', true], cb);
	},

	cyclePause: function(cb)
	{
		cb = cb || noop;
		this.command(['cycle', 'pause'], cb);
	},

	_load: function(media, cb)
	{
		cb = cb || noop;
		this.command(['loadfile', media, 'replace'], cb);
	},

	seek: function(position, cb)
	{
		cb = cb || noop;
		this.command(['seek', position, 'exact+absolute'], cb);
	},

	setVolume: function(value, cb)
	{
		cb = cb || noop;
		this.command(['set_property', 'volume', value * 100], cb);
	},

	setSpeed: function(value, cb)
	{
		cb = cb || noop;
		this.command(['set_property', 'speed', value], cb);
	},

	setRepeat: function(isEnabled, cb)
	{
		cb = cb || noop;

		switch(isEnabled)
		{
			case true:
			case 'inf':
			case 'yes':
			case 'on':
				isEnabled = 'inf';
				break;
			default:
				isEnabled = 'no';
				break;
		}

		this.command(['set_property', 'loop', isEnabled], cb);
	},

	cycleVideo: function(cb)
	{
		cb = cb || noop;
		this.command(['cycle', 'video'], cb);
	},

	cycleAudio: function(cb)
	{
		cb = cb || noop;
		this.command(['cycle', 'audio'], cb);
	},

	cycleSubs: function(cb)
	{
		cb = cb || noop;
		this.command(['cycle', 'sub'], cb);
	},

	addSubs: function(subsPath, cb)
	{
		cb = cb || noop;
		return cb(new Error('Adding subs on MPV not supported yet.'));
	},

	setFullscreen: function(isEnabled, cb)
	{
		cb = cb || noop;

		switch(isEnabled)
		{
			case false:
			case 'no':
				isEnabled = 'no';
				break;
			default:
				isEnabled = 'yes';
				break;
		}

		this.command(['set_property', 'fullscreen', isEnabled], cb);
	},

	cycleFullscreen: function(cb)
	{
		cb = cb || noop;
		this.command(['cycle', 'fullscreen'], cb);
	},

	keepOpen: function(value, cb)
	{
		cb = cb || noop;

		switch(value)
		{
			case true:
			case 'yes':
				value = 'yes';
				break;
			case 'always':
				value = 'always';
				break;
			default:
				value = 'no';
				break;
		}

		this.command(['set_property', 'keep-open', value], cb);
	},

	_playerQuit: function(cb)
	{
		cb = cb || noop;
		this.command(['quit', 0], cb);
	},

	_parseSocketData: function(data)
	{
		const splitOper = data.includes('\r\n') ? '\r\n' : '\n';
		const msgArray = data.split(splitOper);

		for(var i = 0; i < msgArray.length - 1; i++)
		{
			var msg = JSON.parse(msgArray[i]);

			if(msg.event !== 'property-change')
				continue;

			var value = null;

			switch(msg.name)
			{
				case 'volume':
					value = msg.data / 100;
					break;
				case 'time-pos':
					if(
						msg.data < 0
						|| !isNaN(prevPosition)
						&& Math.abs(prevPosition - msg.data) < 1
					) {
						continue;
					}
					value = Math.floor(msg.data);
					prevPosition = value;
					break;
				case 'duration':
				case 'pause':
				case 'eof-reached':
				case 'speed':
				case 'media-title':
					value = msg.data;
					break;
				default:
					break;
			}

			if(value !== null)
				this.emit('playback', { name: msg.name, value: value });
		}
	}
}