/**
* @license
* Copyright 2016 Google Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
goog.provide('shaka.cast.CastReceiver');
goog.require('goog.asserts');
goog.require('shaka.cast.CastUtils');
goog.require('shaka.log');
goog.require('shaka.util.Error');
goog.require('shaka.util.EventManager');
goog.require('shaka.util.FakeEvent');
goog.require('shaka.util.FakeEventTarget');
goog.require('shaka.util.IDestroyable');
goog.require('shaka.util.Platform');
goog.require('shaka.util.Timer');
/**
* A receiver to communicate between the Chromecast-hosted player and the
* sender application.
*
* @constructor
* @struct
* @param {!HTMLMediaElement} video The local video element associated with the
* local Player instance.
* @param {!shaka.Player} player A local Player instance.
* @param {function(Object)=} appDataCallback A callback to handle
* application-specific data passed from the sender. This can come either
* from a Shaka-based sender through CastProxy.setAppData, or from a
* sender using the customData field of the LOAD message of the standard
* Cast message namespace. It can also be null if no such data is sent.
* @param {function(string):string=} contentIdCallback A callback to
* retrieve manifest URI from the provided content id.
* @implements {shaka.util.IDestroyable}
* @extends {shaka.util.FakeEventTarget}
* @export
*/
shaka.cast.CastReceiver =
function(video, player, appDataCallback, contentIdCallback) {
shaka.util.FakeEventTarget.call(this);
/** @private {HTMLMediaElement} */
this.video_ = video;
/** @private {shaka.Player} */
this.player_ = player;
/** @private {shaka.util.EventManager} */
this.eventManager_ = new shaka.util.EventManager();
/** @private {Object} */
this.targets_ = {
'video': video,
'player': player,
};
/** @private {?function(Object)} */
this.appDataCallback_ = appDataCallback || function() {};
/** @private {?function(string):string} */
this.contentIdCallback_ = contentIdCallback ||
/** @param {string} contentId
@return {string} */
function(contentId) { return contentId; };
/** @private {boolean} */
this.isConnected_ = false;
/** @private {boolean} */
this.isIdle_ = true;
/** @private {number} */
this.updateNumber_ = 0;
/** @private {boolean} */
this.startUpdatingUpdateNumber_ = false;
/** @private {boolean} */
this.initialStatusUpdatePending_ = true;
/** @private {cast.receiver.CastMessageBus} */
this.shakaBus_ = null;
/** @private {cast.receiver.CastMessageBus} */
this.genericBus_ = null;
/** @private {shaka.util.Timer} */
this.pollTimer_ = new shaka.util.Timer(() => {
this.pollAttributes_();
});
this.init_();
};
goog.inherits(shaka.cast.CastReceiver, shaka.util.FakeEventTarget);
/**
* @return {boolean} True if the cast API is available and there are receivers.
* @export
*/
shaka.cast.CastReceiver.prototype.isConnected = function() {
return this.isConnected_;
};
/**
* @return {boolean} True if the receiver is not currently doing loading or
* playing anything.
* @export
*/
shaka.cast.CastReceiver.prototype.isIdle = function() {
return this.isIdle_;
};
/**
* Destroys the underlying Player, then terminates the cast receiver app.
*
* @override
* @export
*/
shaka.cast.CastReceiver.prototype.destroy = async function() {
if (this.eventManager_) {
this.eventManager_.release();
this.eventManager_ = null;
}
const waitFor = [];
if (this.player_) {
waitFor.push(this.player_.destroy());
this.player_ = null;
}
if (this.pollTimer_) {
this.pollTimer_.stop();
this.pollTimer_ = null;
}
this.video_ = null;
this.targets_ = null;
this.appDataCallback_ = null;
this.isConnected_ = false;
this.isIdle_ = true;
this.shakaBus_ = null;
this.genericBus_ = null;
await Promise.all(waitFor);
const manager = cast.receiver.CastReceiverManager.getInstance();
manager.stop();
};
/** @private */
shaka.cast.CastReceiver.prototype.init_ = function() {
let manager = cast.receiver.CastReceiverManager.getInstance();
manager.onSenderConnected = this.onSendersChanged_.bind(this);
manager.onSenderDisconnected = this.onSendersChanged_.bind(this);
manager.onSystemVolumeChanged = this.fakeVolumeChangeEvent_.bind(this);
this.genericBus_ = manager.getCastMessageBus(
shaka.cast.CastUtils.GENERIC_MESSAGE_NAMESPACE);
this.genericBus_.onMessage = this.onGenericMessage_.bind(this);
this.shakaBus_ = manager.getCastMessageBus(
shaka.cast.CastUtils.SHAKA_MESSAGE_NAMESPACE);
this.shakaBus_.onMessage = this.onShakaMessage_.bind(this);
if (goog.DEBUG) {
// Sometimes it is useful to load the receiver app in Chrome to work on the
// UI. To avoid log spam caused by the SDK trying to connect to web sockets
// that don't exist, in uncompiled mode we check if the hosting browser is a
// Chromecast before starting the receiver manager. We wouldn't do browser
// detection except for debugging, so only do this in uncompiled mode.
if (shaka.util.Platform.isChromecast()) {
manager.start();
}
} else {
manager.start();
}
shaka.cast.CastUtils.VideoEvents.forEach(function(name) {
this.eventManager_.listen(
this.video_, name, this.proxyEvent_.bind(this, 'video'));
}.bind(this));
shaka.cast.CastUtils.PlayerEvents.forEach(function(name) {
this.eventManager_.listen(
this.player_, name, this.proxyEvent_.bind(this, 'player'));
}.bind(this));
// In our tests, the original Chromecast seems to have trouble decoding above
// 1080p. It would be a waste to select a higher res anyway, given that the
// device only outputs 1080p to begin with.
// Chromecast has an extension to query the device/display's resolution.
if (cast.__platform__ && cast.__platform__.canDisplayType(
'video/mp4; codecs="avc1.640028"; width=3840; height=2160')) {
// The device and display can both do 4k. Assume a 4k limit.
this.player_.setMaxHardwareResolution(3840, 2160);
} else {
// Chromecast has always been able to do 1080p. Assume a 1080p limit.
this.player_.setMaxHardwareResolution(1920, 1080);
}
// Do not start excluding values from update messages until the video is
// fully loaded.
this.eventManager_.listen(this.video_, 'loadeddata', function() {
this.startUpdatingUpdateNumber_ = true;
}.bind(this));
// Maintain idle state.
this.eventManager_.listen(this.player_, 'loading', function() {
// No longer idle once loading. This allows us to show the spinner during
// the initial buffering phase.
this.isIdle_ = false;
this.onCastStatusChanged_();
}.bind(this));
this.eventManager_.listen(this.video_, 'playing', function() {
// No longer idle once playing. This allows us to replay a video without
// reloading.
this.isIdle_ = false;
this.onCastStatusChanged_();
}.bind(this));
this.eventManager_.listen(this.video_, 'pause', function() {
this.onCastStatusChanged_();
}.bind(this));
this.eventManager_.listen(this.player_, 'unloading', function() {
// Go idle when unloading content.
this.isIdle_ = true;
this.onCastStatusChanged_();
}.bind(this));
this.eventManager_.listen(this.video_, 'ended', function() {
// Go idle 5 seconds after 'ended', assuming we haven't started again or
// been destroyed.
const timer = new shaka.util.Timer(() => {
if (this.video_ && this.video_.ended) {
this.isIdle_ = true;
this.onCastStatusChanged_();
}
});
timer.tickAfter(/* seconds= */ 5);
}.bind(this));
// Do not start polling until after the sender's 'init' message is handled.
};
/** @private */
shaka.cast.CastReceiver.prototype.onSendersChanged_ = function() {
// Reset update message frequency values, to make sure whomever joined
// will get a full update message.
this.updateNumber_ = 0;
// Don't reset startUpdatingUpdateNumber_, because this operation does not
// result in new data being loaded.
this.initialStatusUpdatePending_ = true;
let manager = cast.receiver.CastReceiverManager.getInstance();
this.isConnected_ = manager.getSenders().length != 0;
this.onCastStatusChanged_();
};
/**
* Dispatch an event to notify the receiver app that the status has changed.
* @private
*/
shaka.cast.CastReceiver.prototype.onCastStatusChanged_ = function() {
// Do this asynchronously so that synchronous changes to idle state (such as
// Player calling unload() as part of load()) are coalesced before the event
// goes out.
Promise.resolve().then(function() {
if (!this.player_) {
// We've already been destroyed.
return;
}
let event = new shaka.util.FakeEvent('caststatuschanged');
this.dispatchEvent(event);
// Send a media status message, with a media info message if appropriate.
if (!this.maybeSendMediaInfoMessage_()) {
this.sendMediaStatus_();
}
}.bind(this));
};
/**
* Take on initial state from the sender.
* @param {shaka.cast.CastUtils.InitStateType} initState
* @param {Object} appData
* @private
*/
shaka.cast.CastReceiver.prototype.initState_ = function(initState, appData) {
// Take on player state first.
for (let k in initState['player']) {
let v = initState['player'][k];
// All player state vars are setters to be called.
/** @type {Object} */(this.player_)[k](v);
}
// Now process custom app data, which may add additional player configs:
this.appDataCallback_(appData);
let manifestReady = Promise.resolve();
let autoplay = this.video_.autoplay;
// Now load the manifest, if present.
if (initState['manifest']) {
// Don't autoplay the content until we finish setting up initial state.
this.video_.autoplay = false;
manifestReady = this.player_.load(
initState['manifest'], initState['startTime']);
}
// Finally, take on video state and player's "after load" state.
manifestReady.then(() => {
if (!this.player_) {
// We've already been destroyed.
return;
}
for (let k in initState['video']) {
let v = initState['video'][k];
this.video_[k] = v;
}
for (let k in initState['playerAfterLoad']) {
let v = initState['playerAfterLoad'][k];
// All player state vars are setters to be called.
/** @type {Object} */(this.player_)[k](v);
}
// Restore original autoplay setting.
this.video_.autoplay = autoplay;
if (initState['manifest']) {
// Resume playback with transferred state.
this.video_.play();
// Notify generic controllers of the state change.
this.sendMediaStatus_();
}
}, (error) => {
// Pass any errors through to the app.
goog.asserts.assert(error instanceof shaka.util.Error,
'Wrong error type!');
let event = new shaka.util.FakeEvent('error', {'detail': error});
this.player_.dispatchEvent(event);
});
};
/**
* @param {string} targetName
* @param {!Event} event
* @private
*/
shaka.cast.CastReceiver.prototype.proxyEvent_ = function(targetName, event) {
if (!this.player_) {
// The receiver is destroyed, so it should ignore further events.
return;
}
// Poll and send an update right before we send the event. Some events
// indicate an attribute change, so that change should be visible when the
// event is handled.
this.pollAttributes_();
this.sendMessage_({
'type': 'event',
'targetName': targetName,
'event': event,
}, this.shakaBus_);
};
/** @private */
shaka.cast.CastReceiver.prototype.pollAttributes_ = function() {
// The poll timer may have been pre-empted by an event (e.g. timeupdate).
// Calling |start| will cancel any pending calls and therefore will avoid us
// polling too often.
this.pollTimer_.tickAfter(/* seconds= */ 0.5);
let update = {
'video': {},
'player': {},
};
shaka.cast.CastUtils.VideoAttributes.forEach(function(name) {
update['video'][name] = this.video_[name];
}.bind(this));
// TODO: Instead of this variable frequency update system, instead cache the
// previous player state and only send over changed values, with complete
// updates every ~20 updates to account for dropped messages.
if (this.player_.isLive()) {
for (let name in shaka.cast.CastUtils.PlayerGetterMethodsThatRequireLive) {
let frequency =
shaka.cast.CastUtils.PlayerGetterMethodsThatRequireLive[name];
if (this.updateNumber_ % frequency == 0) {
update['player'][name] = /** @type {Object} */ (this.player_)[name]();
}
}
}
for (let name in shaka.cast.CastUtils.PlayerGetterMethods) {
let frequency = shaka.cast.CastUtils.PlayerGetterMethods[name];
if (this.updateNumber_ % frequency == 0) {
update['player'][name] = /** @type {Object} */ (this.player_)[name]();
}
}
// Volume attributes are tied to the system volume.
let manager = cast.receiver.CastReceiverManager.getInstance();
let systemVolume = manager.getSystemVolume();
if (systemVolume) {
update['video']['volume'] = systemVolume.level;
update['video']['muted'] = systemVolume.muted;
}
// Only start progressing the update number once data is loaded,
// just in case any of the "rarely changing" properties with less frequent
// update messages changes significantly during the loading process.
if (this.startUpdatingUpdateNumber_) {
this.updateNumber_ += 1;
}
this.sendMessage_({
'type': 'update',
'update': update,
}, this.shakaBus_);
this.maybeSendMediaInfoMessage_();
};
/**
* Composes and sends a mediaStatus message if appropriate.
* @return {boolean}
* @private
*/
shaka.cast.CastReceiver.prototype.maybeSendMediaInfoMessage_ = function() {
if (this.initialStatusUpdatePending_ &&
(this.video_.duration || this.player_.isLive())) {
// Send over a media status message to set the duration of the cast
// dialogue.
this.sendMediaInfoMessage_();
this.initialStatusUpdatePending_ = false;
return true;
}
return false;
};
/**
* Composes and sends a mediaStatus message with a mediaInfo component.
*
* @param {number=} requestId
* @private
*/
shaka.cast.CastReceiver.prototype.sendMediaInfoMessage_ =
function(requestId = 0) {
let media = {
'contentId': this.player_.getAssetUri(),
'streamType': this.player_.isLive() ? 'LIVE' : 'BUFFERED',
// TODO: Is there a use case when this would be required?
// Sending an empty string for now since it's a mandatory
// field.
'contentType': '',
};
if (!this.player_.isLive()) {
// Optional, and only sent when the duration is known.
media['duration'] = this.video_.duration;
}
this.sendMediaStatus_(requestId, media);
};
/**
* Dispatch a fake 'volumechange' event to mimic the video element, since volume
* changes are routed to the system volume on the receiver.
* @private
*/
shaka.cast.CastReceiver.prototype.fakeVolumeChangeEvent_ = function() {
// Volume attributes are tied to the system volume.
let manager = cast.receiver.CastReceiverManager.getInstance();
let systemVolume = manager.getSystemVolume();
goog.asserts.assert(systemVolume, 'System volume should not be null!');
if (systemVolume) {
// Send an update message with just the latest volume level and muted state.
this.sendMessage_({
'type': 'update',
'update': {
'video': {
'volume': systemVolume.level,
'muted': systemVolume.muted,
},
},
}, this.shakaBus_);
}
// Send another message with a 'volumechange' event to update the sender's UI.
this.sendMessage_({
'type': 'event',
'targetName': 'video',
'event': {'type': 'volumechange'},
}, this.shakaBus_);
};
/**
* Since this method is in the compiled library, make sure all messages are
* read with quoted properties.
* @param {!cast.receiver.CastMessageBus.Event} event
* @private
*/
shaka.cast.CastReceiver.prototype.onShakaMessage_ = function(event) {
let message = shaka.cast.CastUtils.deserialize(event.data);
shaka.log.debug('CastReceiver: message', message);
switch (message['type']) {
case 'init':
// Reset update message frequency values after initialization.
this.updateNumber_ = 0;
this.startUpdatingUpdateNumber_ = false;
this.initialStatusUpdatePending_ = true;
this.initState_(message['initState'], message['appData']);
// The sender is supposed to reflect the cast system volume after
// connecting. Using fakeVolumeChangeEvent_() would create a race on the
// sender side, since it would have volume properties, but no others.
// This would lead to hasRemoteProperties() being true, even though a
// complete set had never been sent.
// Now that we have init state, this is a good time for the first update
// message anyway.
this.pollAttributes_();
break;
case 'appData':
this.appDataCallback_(message['appData']);
break;
case 'set': {
let targetName = message['targetName'];
let property = message['property'];
let value = message['value'];
if (targetName == 'video') {
// Volume attributes must be rerouted to the system.
let manager = cast.receiver.CastReceiverManager.getInstance();
if (property == 'volume') {
manager.setSystemVolumeLevel(value);
break;
} else if (property == 'muted') {
manager.setSystemVolumeMuted(value);
break;
}
}
this.targets_[targetName][property] = value;
break;
}
case 'call': {
let targetName = message['targetName'];
let methodName = message['methodName'];
let args = message['args'];
let target = this.targets_[targetName];
target[methodName].apply(target, args);
break;
}
case 'asyncCall': {
let targetName = message['targetName'];
let methodName = message['methodName'];
if (targetName == 'player' && methodName == 'load') {
// Reset update message frequency values after a load.
this.updateNumber_ = 0;
this.startUpdatingUpdateNumber_ = false;
}
let args = message['args'];
let id = message['id'];
let senderId = event.senderId;
let target = this.targets_[targetName];
let p = target[methodName].apply(target, args);
if (targetName == 'player' && methodName == 'load') {
// Wait until the manifest has actually loaded to send another media
// info message, so on a new load it doesn't send the old info over.
p = p.then(function() {
this.initialStatusUpdatePending_ = true;
}.bind(this));
}
// Replies must go back to the specific sender who initiated, so that we
// don't have to deal with conflicting IDs between senders.
p.then(this.sendAsyncComplete_.bind(this, senderId, id, /* error */ null),
this.sendAsyncComplete_.bind(this, senderId, id));
break;
}
}
};
/**
* @param {!cast.receiver.CastMessageBus.Event} event
* @private
*/
shaka.cast.CastReceiver.prototype.onGenericMessage_ = function(event) {
let message = shaka.cast.CastUtils.deserialize(event.data);
shaka.log.debug('CastReceiver: message', message);
// TODO(ismena): error message on duplicate request id from the same sender
switch (message['type']) {
case 'PLAY':
this.video_.play();
// Notify generic controllers that the player state changed.
// requestId=0 (the parameter) means that the message was not
// triggered by a GET_STATUS request.
this.sendMediaStatus_();
break;
case 'PAUSE':
this.video_.pause();
this.sendMediaStatus_();
break;
case 'SEEK': {
let currentTime = message['currentTime'];
let resumeState = message['resumeState'];
if (currentTime != null) {
this.video_.currentTime = Number(currentTime);
}
if (resumeState && resumeState == 'PLAYBACK_START') {
this.video_.play();
this.sendMediaStatus_();
} else if (resumeState && resumeState == 'PLAYBACK_PAUSE') {
this.video_.pause();
this.sendMediaStatus_();
}
break;
}
case 'STOP':
this.player_.unload().then(function() {
if (!this.player_) {
// We've already been destroyed.
return;
}
this.sendMediaStatus_();
}.bind(this));
break;
case 'GET_STATUS':
// TODO(ismena): According to the SDK this is supposed to be a
// unicast message to the sender that requested the status,
// but it doesn't appear to be working.
// Look into what's going on there and change this to be a
// unicast.
this.sendMediaInfoMessage_(Number(message['requestId']));
break;
case 'VOLUME': {
let volumeObject = message['volume'];
let level = volumeObject['level'];
let muted = volumeObject['muted'];
let oldVolumeLevel = this.video_.volume;
let oldVolumeMuted = this.video_.muted;
if (level != null) {
this.video_.volume = Number(level);
}
if (muted != null) {
this.video_.muted = muted;
}
// Notify generic controllers if the volume changed.
if (oldVolumeLevel != this.video_.volume ||
oldVolumeMuted != this.video_.muted) {
this.sendMediaStatus_();
}
break;
}
case 'LOAD': {
// Reset update message frequency values after a load.
this.updateNumber_ = 0;
this.startUpdatingUpdateNumber_ = false;
this.initialStatusUpdatePending_ = false; // This already sends an update.
let mediaInfo = message['media'];
let contentId = mediaInfo['contentId'];
let currentTime = message['currentTime'];
let assetUri = this.contentIdCallback_(contentId);
let autoplay = message['autoplay'] || true;
let customData = mediaInfo['customData'];
this.appDataCallback_(customData);
if (autoplay) {
this.video_.autoplay = true;
}
this.player_.load(assetUri, currentTime).then(function() {
if (!this.player_) {
// We've already been destroyed.
return;
}
// Notify generic controllers that the media has changed.
this.sendMediaInfoMessage_();
}.bind(this)).catch(function(error) {
// Load failed. Dispatch the error message to the sender.
let type = 'LOAD_FAILED';
if (error.category == shaka.util.Error.Category.PLAYER &&
error.code == shaka.util.Error.Code.LOAD_INTERRUPTED) {
type = 'LOAD_CANCELLED';
}
this.sendMessage_({
'requestId': Number(message['requestId']),
'type': type,
}, this.genericBus_);
}.bind(this));
break;
}
default:
shaka.log.warning(
'Unrecognized message type from the generic Chromecast controller!',
message['type']);
// Dispatch an error to the sender.
this.sendMessage_({
'requestId': Number(message['requestId']),
'type': 'INVALID_REQUEST',
'reason': 'INVALID_COMMAND',
}, this.genericBus_);
break;
}
};
/**
* Tell the sender that the async operation is complete.
* @param {string} senderId
* @param {string} id
* @param {shaka.util.Error} error
* @private
*/
shaka.cast.CastReceiver.prototype.sendAsyncComplete_ =
function(senderId, id, error) {
if (!this.player_) {
// We've already been destroyed.
return;
}
this.sendMessage_({
'type': 'asyncComplete',
'id': id,
'error': error,
}, this.shakaBus_, senderId);
};
/**
* Since this method is in the compiled library, make sure all messages passed
* in here were created with quoted property names.
* @param {!Object} message
* @param {cast.receiver.CastMessageBus} bus
* @param {string=} senderId
* @private
*/
shaka.cast.CastReceiver.prototype.sendMessage_ =
function(message, bus, senderId) {
// Cuts log spam when debugging the receiver UI in Chrome.
if (!this.isConnected_) return;
let serialized = shaka.cast.CastUtils.serialize(message);
if (senderId) {
bus.getCastChannel(senderId).send(serialized);
} else {
bus.broadcast(serialized);
}
};
/**
* @return {string}
* @private
*/
shaka.cast.CastReceiver.prototype.getPlayState_ = function() {
let playState = shaka.cast.CastReceiver.PLAY_STATE;
if (this.isIdle_) {
return playState.IDLE;
} else if (this.player_.isBuffering()) {
return playState.BUFFERING;
} else if (this.video_.paused) {
return playState.PAUSED;
} else {
return playState.PLAYING;
}
};
/**
* @param {number=} requestId
* @param {Object=} media
* @private
*/
shaka.cast.CastReceiver.prototype.sendMediaStatus_ =
function(requestId = 0, media = null) {
let mediaStatus = {
// mediaSessionId is a unique ID for the playback of this specific session.
// It's used to identify a specific instance of a playback.
// We don't support multiple playbacks, so just return 0.
'mediaSessionId': 0,
'playbackRate': this.video_.playbackRate,
'playerState': this.getPlayState_(),
'currentTime': this.video_.currentTime,
// supportedMediaCommands is a sum of all the flags of commands that the
// player supports.
// The list of comands with respective flags is:
// 1 - Pause
// 2 - Seek
// 4 - Stream volume
// 8 - Stream mute
// 16 - Skip forward
// 32 - Skip backward
// We support all of them, and their sum is 63.
'supportedMediaCommands': 63,
'volume': {
'level': this.video_.volume,
'muted': this.video_.muted,
},
};
if (media) {
mediaStatus['media'] = media;
}
let ret = {
'requestId': requestId,
'type': 'MEDIA_STATUS',
'status': [mediaStatus],
};
this.sendMessage_(ret, this.genericBus_);
};
/**
* @enum {string}
*/
shaka.cast.CastReceiver.PLAY_STATE = {
IDLE: 'IDLE',
PLAYING: 'PLAYING',
BUFFERING: 'BUFFERING',
PAUSED: 'PAUSED',
};