infusion
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Infusion is an application framework for developing flexible stuff with JavaScript
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JavaScript
/*
Copyright 2018 OCAD University
Licensed under the Educational Community License (ECL), Version 2.0 or the New
BSD license. You may not use this file except in compliance with one these
Licenses.
You may obtain a copy of the ECL 2.0 License and BSD License at
https://github.com/fluid-project/infusion/raw/master/Infusion-LICENSE.txt
*/
/* global YT */
var fluid_3_0_0 = fluid_3_0_0 || {};
(function ($, fluid) {
"use strict";
/*******************************************************************************
* captions
*
* An enactor that is capable of enabling captions on embedded YouTube videos
*******************************************************************************/
fluid.defaults("fluid.prefs.enactor.captions", {
gradeNames: ["fluid.prefs.enactor", "fluid.viewComponent"],
preferenceMap: {
"fluid.prefs.captions": {
"model.enabled": "value"
}
},
events: {
onVideoElementLocated: null
},
selectors: {
videos: "iframe[src^=\"https://www.youtube.com/embed/\"]"
},
model: {
enabled: false
},
components: {
ytAPI: {
type: "fluid.prefs.enactor.captions.ytAPI"
}
},
dynamicComponents: {
player: {
type: "fluid.prefs.enactor.captions.youTubePlayer",
createOnEvent: "onVideoElementLocated",
container: "{arguments}.0",
options: {
model: {
captions: "{captions}.model.enabled"
}
}
}
},
listeners: {
"onCreate.initPlayers": "{that}.initPlayers"
},
invokers: {
initPlayers: {
funcName: "fluid.prefs.enactor.captions.initPlayers",
args: ["{that}", "{ytAPI}.notifyWhenLoaded", "{that}.dom.videos"]
}
}
});
/**
* When the YouTube API is available, the onVideoElementLocated event will fire for each video element located by
* the `videos` argument. Each of these event calls will fire with a jQuery object containing a single video
* element. This allows for initializing dynamicComponents (fluid.prefs.enactor.captions.youTubePlayer) for each
* video element.
*
* @param {Component} that - the component
* @param {Function} getYtApi - a function that returns a promise indicating if the YouTube API is available
* @param {jQuery|Element} videos - the videos to fire onVideoElementLocated events with
*
* @return {Promise} - A promise that follows the promise returned by the getYtApi function
*/
fluid.prefs.enactor.captions.initPlayers = function (that, getYtApi, videos) {
var promise = fluid.promise();
var ytAPINotice = getYtApi();
promise.then(function () {
$(videos).each(function (index, elm) {
that.events.onVideoElementLocated.fire($(elm));
});
});
fluid.promise.follow(ytAPINotice, promise);
return promise;
};
/*********************************************************************************************
* fluid.prefs.enactor.captions.window is a singleton component to be used for assigning *
* values onto the window object. *
*********************************************************************************************/
fluid.defaults("fluid.prefs.enactor.captions.ytAPI", {
gradeNames: ["fluid.component", "fluid.resolveRootSingle"],
singleRootType: "fluid.prefs.enactor.captions.window",
events: {
onYouTubeAPILoaded: null
},
members: {
global: window
},
invokers: {
notifyWhenLoaded: {
funcName: "fluid.prefs.enactor.captions.ytAPI.notifyWhenLoaded",
args: ["{that}"]
}
}
});
/**
* Used to determine when the YouTube API is available for use. It will test if the API is already available, and if
* not, will bind to the onYouTubeIframeAPIReady method that is called when the YouTube API finishes loading.
* When the YouTube API is ready, the promise will resolve an the onYouTubeAPILoaded event will fire.
*
* NOTE: After FLUID-6148 (https://issues.fluidproject.org/browse/FLUID-6148) is complete, it should be possible for
* the framework to handle this asynchrony directly in an expander for the player member in
* fluid.prefs.enactor.captions.youTubePlayer.
*
* @param {Component} that - the component itself
*
* @return {Promise} - a promise resolved after the YouTube API has loaded.
*/
fluid.prefs.enactor.captions.ytAPI.notifyWhenLoaded = function (that) {
var promise = fluid.promise();
promise.then(function () {
that.events.onYouTubeAPILoaded.fire();
}, function (error) {
fluid.log(fluid.logLevel.WARN, error);
});
if (fluid.get(window, ["YT", "Player"])) {
promise.resolve();
} else {
// the YouTube iframe api will call onYouTubeIframeAPIReady after the api has loaded
fluid.set(that.global, "onYouTubeIframeAPIReady", promise.resolve);
}
return promise;
};
/**
* See: https://developers.google.com/youtube/iframe_api_reference#Events for details on the YouTube player
* events. This includes when they are fired and what data is passed along.
*/
fluid.defaults("fluid.prefs.enactor.captions.youTubePlayer", {
gradeNames: ["fluid.viewComponent"],
events: {
onReady: null,
onStateChange: null,
onPlaybackQualityChange: null,
onPlaybackRateChange: null,
onError: null,
onApiChange: null
},
model: {
captions: false,
track: {}
},
members: {
player: {
expander: {
funcName: "fluid.prefs.enactor.captions.youTubePlayer.initYTPlayer",
args: ["{that}"]
}
},
tracklist: []
},
invokers: {
applyCaptions: {
funcName: "fluid.prefs.enactor.captions.youTubePlayer.applyCaptions",
args: ["{that}.player", "{that}.model.track", "{that}.model.captions"]
}
},
modelListeners: {
"setCaptions": {
listener: "{that}.applyCaptions",
path: ["captions", "track"],
excludeSource: "init"
}
},
listeners: {
"onApiChange.prepTrack": {
listener: "fluid.prefs.enactor.captions.youTubePlayer.prepTrack",
args: ["{that}", "{that}.player"]
},
"onApiChange.applyCaptions": {
listener: "{that}.applyCaptions",
priority: "after:prepTrack"
}
}
});
/**
* Adds the "enablejsapi=1" query parameter to the query string at the end of the src attribute.
* If "enablejsapi" already exists it will modify its value to 1. This is required for API access
* to the embedded YouTube video.
*
* @param {jQuery|Element} videoElm - a reference to the existing embedded YouTube video.
*/
fluid.prefs.enactor.captions.youTubePlayer.enableJSAPI = function (videoElm) {
videoElm = $(videoElm);
var url = new URL(videoElm.attr("src"));
url.searchParams.set("enablejsapi", 1);
videoElm.attr("src", url.toString());
};
/**
* An instance of a YouTube player from the YouTube iframe API
*
* @typedef {Object} YTPlayer
*/
/**
* Initializes the YT.Player using the existing embedded video (component's container). An ID will be added to the
* video element if one does not already exist.
*
* @param {Component} that - the component
* @return {YTPlayer} - an instance of a YouTube player controlling the embedded video
*/
fluid.prefs.enactor.captions.youTubePlayer.initYTPlayer = function (that) {
var id = fluid.allocateSimpleId(that.container);
fluid.prefs.enactor.captions.youTubePlayer.enableJSAPI(that.container);
return new YT.Player(id, {
events: {
onReady: that.events.onReady.fire,
onStateChange: that.events.onStateChange.fire,
onPlaybackQualityChange: that.events.onPlaybackQualityChange.fire,
onPlaybackRateChange: that.events.onPlaybackRateChange.fire,
onError: that.events.onError.fire,
onApiChange: that.events.onApiChange.fire
}
});
};
/**
* Enables/disables the captions on an embedded YouTube video. Requires that the player be initiallized and the API
* ready for use.
*
* @param {YTPlayer} player - an instance of a YouTube player
* @param {Object} track - a track object for the {YTPlayer}
* @param {Boolean} state - true - captions enabled; false - captions disabled.
*/
fluid.prefs.enactor.captions.youTubePlayer.applyCaptions = function (player, track, state) {
// The loadModule method from the player must be ready first. This is made available after
// the onApiChange event has fired.
if (player.loadModule) {
if (state) {
player.loadModule("captions");
player.setOption("captions", "track", track);
} else {
player.unloadModule("captions");
}
}
};
/**
* Prepares the track to be used when captions are enabled. It will use the first track in the tracklist, and update
* the "track" model path with it.
*
* @param {Component} that - the component
* @param {YTPlayer} player - an instance of a YouTube player
*/
fluid.prefs.enactor.captions.youTubePlayer.prepTrack = function (that, player) {
player.loadModule("captions");
var tracklist = player.getOption("captions", "tracklist");
if (tracklist.length && !that.tracklist.length) {
// set the tracklist and use first track for the captions
that.tracklist = tracklist;
that.applier.change("track", tracklist[0], "ADD", "prepTrack");
}
};
})(jQuery, fluid_3_0_0);