BADGER-130: Test CDN failover (extended plugin functionality) (#413)

* feat: implemented functional plugins w/ context

* fix: accounted for optional use of onPluginContextUpdated callback

* chore: moved subtitle cdn failover logic to subtitles.js

* chore: added onContextUpdated plugin event / removed functional plugins

* fix: comments

* fix: comments

Author: JoeBBC

src/bigscreenplayer.js

@@ -307,6 +307,8 @@ function BigscreenPlayer() {
             callbacks.onError(reason)
           }
         })
+
+      Plugins.updateContext((context) => ({ ...context, mediaSources }))
     },
 
     /**
@@ -737,7 +739,7 @@ function BigscreenPlayer() {
     },
 
     /**
-     * Register a plugin for extended events.
+     * Register a plugin for extended events & custom functionality.
      * @function
      * @param {*} plugin
      */

src/playercomponent.js

@@ -335,6 +335,9 @@ function PlayerComponent(
       })
   }
 
+  // Not an ideal place for this, but I've been warned of a possible playercomponent rewrite
+  Plugins.updateContext((context) => ({ ...context, attemptCdnFailover }))
+
   function clearFatalErrorTimeout() {
     if (fatalErrorTimeout !== null) {
       clearTimeout(fatalErrorTimeout)

src/plugins.js

@@ -2,6 +2,7 @@ import PlaybackUtils from "./utils/playbackutils"
 import CallCallbacks from "./utils/callcallbacks"
 
 let plugins = []
+const pluginContext = {}
 
 function callOnAllPlugins(funcKey, evt) {
   const clonedEvent = PlaybackUtils.deepClone(evt)
@@ -13,8 +14,37 @@ function callOnAllPlugins(funcKey, evt) {
 }
 
 export default {
+  /**
+   * @param {function (*): *} updater - a function which accepts the current context, and returns a new context
+   */
+  updateContext: (updater) => {
+    const newContext = updater(PlaybackUtils.deepClone(pluginContext))
+
+    if (typeof newContext !== "object") {
+      throw new TypeError("context must be an object")
+    }
+
+    // update object (preserving reference)
+    for (const prop of Object.keys(pluginContext)) {
+      delete pluginContext[prop]
+    }
+
+    Object.assign(pluginContext, newContext)
+
+    // call context update handlers
+    for (const plugin of plugins) {
+      plugin.onContextUpdated?.(pluginContext)
+    }
+  },
+
+  /**
+   * @param {*} plugin - an object
+   */
   registerPlugin: (plugin) => {
     plugins.push(plugin)
+
+    // provide initial context
+    plugin.onContextUpdated?.(pluginContext)
   },
 
   unregisterPlugin: (plugin) => {

src/subtitles/imscsubtitles.test.js

@@ -7,6 +7,7 @@ import Plugins from "../plugins"
 jest.mock("smp-imsc")
 jest.mock("../utils/loadurl")
 jest.mock("../plugins", () => ({
+  updateContext: jest.fn(),
   interface: {
     onSubtitlesTimeout: jest.fn(),
     onSubtitlesXMLError: jest.fn(),

src/subtitles/legacysubtitles.test.js

@@ -6,6 +6,7 @@ import Renderer from "./renderer"
 
 jest.mock("../utils/loadurl")
 jest.mock("../plugins", () => ({
+  updateContext: jest.fn(),
   interface: {
     onSubtitlesTimeout: jest.fn(),
     onSubtitlesXMLError: jest.fn(),

src/subtitles/subtitles.js

@@ -133,6 +133,16 @@ function Subtitles(
     subtitlesContainer?.tearDown()
   }
 
+  function attemptSubtitleCdnFailover(opts) {
+    hide()
+    mediaSources
+      .failoverSubtitles(opts)
+      .then(() => show())
+      .catch(() => DebugTool.info("No more CDNs available for subtitle failover"))
+  }
+
+  Plugins.updateContext((context) => ({ ...context, attemptSubtitleCdnFailover }))
+
   return {
     enable,
     disable,