feat: set up required key sessions on waitingforkey event (#1232)

If a waitingforkey event is fired, try to set up new key
sessions, as the manifest may have new key information.

Co-authored-by: Gary Katsevman <git@gkatsev.com>

src/videojs-http-streaming.js

@@ -1004,6 +1004,41 @@ class VhsHandler extends Component {
     this.tech_.src(this.mediaSourceUrl_);
   }
 
+  createKeySessions_() {
+    const audioPlaylistLoader =
+      this.masterPlaylistController_.mediaTypes_.AUDIO.activePlaylistLoader;
+
+    this.logger_('waiting for EME key session creation');
+    waitForKeySessionCreation({
+      player: this.player_,
+      sourceKeySystems: this.source_.keySystems,
+      audioMedia: audioPlaylistLoader && audioPlaylistLoader.media(),
+      mainPlaylists: this.playlists.master.playlists
+    }).then(() => {
+      this.logger_('created EME key session');
+      this.masterPlaylistController_.sourceUpdater_.initializedEme();
+    }).catch((err) => {
+      this.logger_('error while creating EME key session', err);
+      this.player_.error({
+        message: 'Failed to initialize media keys for EME',
+        code: 3
+      });
+    });
+  }
+
+  handleWaitingForKey_() {
+    // If waitingforkey is fired, it's possible that the data that's necessary to retrieve
+    // the key is in the manifest. While this should've happened on initial source load, it
+    // may happen again in live streams where the keys change, and the manifest info
+    // reflects the update.
+    //
+    // Because videojs-contrib-eme compares the PSSH data we send to that of PSSH data it's
+    // already requested keys for, we don't have to worry about this generating extraneous
+    // requests.
+    this.logger_('waitingforkey fired, attempting to create any new key sessions');
+    this.createKeySessions_();
+  }
+
   /**
    * If necessary and EME is available, sets up EME options and waits for key session
    * creation.
@@ -1033,6 +1068,9 @@ class VhsHandler extends Component {
       }
     });
 
+    this.handleWaitingForKey_ = this.handleWaitingForKey_.bind(this);
+    this.player_.tech_.on('waitingforkey', this.handleWaitingForKey_);
+
     // In IE11 this is too early to initialize media keys, and IE11 does not support
     // promises.
     if (videojs.browser.IE_VERSION === 11 || !didSetupEmeOptions) {
@@ -1041,22 +1079,7 @@ class VhsHandler extends Component {
       return;
     }
 
-    this.logger_('waiting for EME key session creation');
-    waitForKeySessionCreation({
-      player: this.player_,
-      sourceKeySystems: this.source_.keySystems,
-      audioMedia: audioPlaylistLoader && audioPlaylistLoader.media(),
-      mainPlaylists: this.playlists.master.playlists
-    }).then(() => {
-      this.logger_('created EME key session');
-      this.masterPlaylistController_.sourceUpdater_.initializedEme();
-    }).catch((err) => {
-      this.logger_('error while creating EME key session', err);
-      this.player_.error({
-        message: 'Failed to initialize media keys for EME',
-        code: 3
-      });
-    });
+    this.createKeySessions_();
   }
 
   /**
@@ -1171,6 +1194,10 @@ class VhsHandler extends Component {
       this.mediaSourceUrl_ = null;
     }
 
+    if (this.tech_) {
+      this.tech_.off('waitingforkey', this.handleWaitingForKey_);
+    }
+
     super.dispose();
   }
 

test/videojs-http-streaming.test.js

@@ -4713,6 +4713,45 @@ QUnit.test('eme handles keystatuschange where status is usable', function(assert
   assert.deepEqual(excludes, [], 'did not exclude anything');
 });
 
+QUnit.test('eme waitingforkey event triggers another setup', function(assert) {
+  this.player.eme = { options: { setting: 1 } };
+  this.player.src({
+    src: 'manifest/master.m3u8',
+    type: 'application/x-mpegURL',
+    keySystems: { keySystem1: { url: 'url1' } }
+  });
+
+  this.clock.tick(1);
+
+  const media = {
+    attributes: { CODECS: 'avc1.420015, mp4a.40.2c' },
+    contentProtection: { keySystem1: { pssh: 'test' } }
+  };
+
+  const vhs = this.player.tech_.vhs;
+
+  vhs.playlists = {
+    master: { playlists: [media] },
+    media: () => media
+  };
+
+  const origCreateKeySessions = vhs.createKeySessions_.bind(vhs);
+  let createKeySessionCalls = 0;
+
+  vhs.createKeySessions_ = () => {
+    createKeySessionCalls++;
+    origCreateKeySessions();
+  };
+
+  vhs.masterPlaylistController_.sourceUpdater_.trigger('createdsourcebuffers');
+
+  assert.equal(createKeySessionCalls, 1, 'called createKeySessions_ once');
+
+  this.player.tech_.trigger({type: 'waitingforkey', status: 'usable'});
+
+  assert.equal(createKeySessionCalls, 2, 'called createKeySessions_ again');
+});
+
 QUnit.test('integration: configures eme for DASH on source buffer creation', function(assert) {
   assert.timeout(3000);
   const done = assert.async();