feat: add option to cache encrpytion keys in the player

README.md

@@ -40,6 +40,7 @@ Video.js Compatibility: 6.0, 7.0
       - [Source](#source)
     - [List](#list)
       - [withCredentials](#withcredentials)
+      - [handleManifestRedirects](#handlemanifestredirects)
       - [useCueTags](#usecuetags)
       - [overrideNative](#overridenative)
       - [blacklistDuration](#blacklistduration)
@@ -51,6 +52,7 @@ Video.js Compatibility: 6.0, 7.0
       - [allowSeeksWithinUnsafeLiveWindow](#allowseekswithinunsafelivewindow)
       - [customTagParsers](#customtagparsers)
       - [customTagMappers](#customtagmappers)
+      - [cacheEncryptionKeys](#cacheencryptionkeys)
   - [Runtime Properties](#runtime-properties)
     - [hls.playlists.master](#hlsplaylistsmaster)
     - [hls.playlists.media](#hlsplaylistsmedia)
@@ -418,6 +420,14 @@ With `customTagParsers` you can pass an array of custom m3u8 tag parser objects.
 
 Similar to `customTagParsers`, with `customTagMappers` you can pass an array of custom m3u8 tag mapper objects. See https://github.com/videojs/m3u8-parser#custom-parsers
 
+##### cacheEncryptionKeys
+* Type: `boolean`
+* can be used as a source option
+* can be used as an initialization option
+
+This option forces the player to cache AES-128 encryption keys internally instead of requesting the key alongside every segment request.
+This option defaults to `false`.
+
 ### Runtime Properties
 Runtime properties are attached to the tech object when HLS is in
 use. You can get a reference to the HLS source handler like this:

src/bin-utils.js

@@ -75,6 +75,13 @@ export const initSegmentId = function(initSegment) {
   ].join(',');
 };
 
+/**
+ * Returns a unique string identifier for a media segment key.
+ */
+export const segmentKeyId = function(key) {
+  return key.resolvedUri;
+};
+
 /**
  * utils to help dump binary data to the console
  */

src/master-playlist-controller.js

@@ -64,7 +64,8 @@ export class MasterPlaylistController extends videojs.EventTarget {
       blacklistDuration,
       enableLowInitialPlaylist,
       sourceType,
-      seekTo
+      seekTo,
+      cacheEncryptionKeys
     } = options;
 
     if (!url) {
@@ -125,7 +126,8 @@ export class MasterPlaylistController extends videojs.EventTarget {
       syncController: this.syncController_,
       decrypter: this.decrypter_,
       sourceType: this.sourceType_,
-      inbandTextTracks: this.inbandTextTracks_
+      inbandTextTracks: this.inbandTextTracks_,
+      cacheEncryptionKeys
     };
 
     this.masterPlaylistLoader_ = this.sourceType_ === 'dash' ?

src/media-segment-request.js

@@ -285,16 +285,18 @@ const decryptSegment = (decrypter, segment, doneFn) => {
 
   decrypter.addEventListener('message', decryptionHandler);
 
+  const keyBytes = segment.key.bytes.slice();
+
   // this is an encrypted segment
   // incrementally decrypt the segment
   decrypter.postMessage(createTransferableMessage({
     source: segment.requestId,
     encrypted: segment.encryptedBytes,
-    key: segment.key.bytes,
+    key: keyBytes,
     iv: segment.key.iv
   }), [
     segment.encryptedBytes.buffer,
-    segment.key.bytes.buffer
+    keyBytes.buffer
   ]);
 };
 
@@ -432,7 +434,7 @@ export const mediaSegmentRequest = (xhr,
   const finishProcessingFn = waitForCompletion(activeXhrs, decryptionWorker, doneFn);
 
   // optionally, request the decryption key
-  if (segment.key) {
+  if (segment.key && !segment.key.bytes) {
     const keyRequestOptions = videojs.mergeOptions(xhrOptions, {
       uri: segment.key.resolvedUri,
       responseType: 'arraybuffer'

src/segment-loader.js

@@ -7,7 +7,7 @@ import SourceUpdater from './source-updater';
 import Config from './config';
 import window from 'global/window';
 import { removeCuesFromTrack } from './mse/remove-cues-from-track';
-import { initSegmentId } from './bin-utils';
+import { initSegmentId, segmentKeyId } from './bin-utils';
 import { mediaSegmentRequest, REQUEST_ERRORS } from './media-segment-request';
 import { TIME_FUDGE_FACTOR, timeUntilRebuffer as timeUntilRebuffer_ } from './ranges';
 import { minRebufferMaxBandwidthSelector } from './playlist-selectors';
@@ -183,6 +183,11 @@ export default class SegmentLoader extends videojs.EventTarget {
     // Fragmented mp4 playback
     this.activeInitSegmentId_ = null;
     this.initSegments_ = {};
+
+    // HLSe playback
+    this.cacheEncryptionKeys_ = settings.cacheEncryptionKeys;
+    this.keyCache_ = {};
+
     // Fmp4 CaptionParser
     this.captionParser_ = new CaptionParser();
 
@@ -342,6 +347,8 @@ export default class SegmentLoader extends videojs.EventTarget {
     const id = initSegmentId(map);
     let storedMap = this.initSegments_[id];
 
+    // TODO: We should use the HTTP Expires header to invalidate our cache per
+    // https://tools.ietf.org/html/draft-pantos-http-live-streaming-23#section-6.2.3
     if (set && !storedMap && map.bytes) {
       this.initSegments_[id] = storedMap = {
         resolvedUri: map.resolvedUri,
@@ -355,6 +362,42 @@ export default class SegmentLoader extends videojs.EventTarget {
     return storedMap || map;
   }
 
+  /**
+   * Gets and sets key for the provided key
+   *
+   * @param {Object} key
+   *        The key object representing the key to get or set
+   * @param {Boolean=} set
+   *        If true, the key for the provided key should be saved
+   * @return {Object}
+   *         Key object for desired key
+   */
+  segmentKey(key, set = false) {
+    if (!key) {
+      return null;
+    }
+
+    const id = segmentKeyId(key);
+    let storedKey = this.keyCache_[id];
+
+    if (this.cacheEncryptionKeys_ && set && !storedKey && key.bytes) {
+      this.keyCache_[id] = storedKey = {
+        resolvedUri: key.resolvedUri,
+        bytes: key.bytes
+      };
+    }
+
+    const result = {
+      resolvedUri: (storedKey || key).resolvedUri
+    };
+
+    if (storedKey) {
+      result.bytes = storedKey.bytes;
+    }
+
+    return result;
+  }
+
   /**
    * Returns true if all configuration required for loading is present, otherwise false.
    *
@@ -1048,10 +1091,8 @@ export default class SegmentLoader extends videojs.EventTarget {
         0, 0, 0, segmentInfo.mediaIndex + segmentInfo.playlist.mediaSequence
       ]);
 
-      simpleSegment.key = {
-        resolvedUri: segment.key.resolvedUri,
-        iv
-      };
+      simpleSegment.key = this.segmentKey(segment.key);
+      simpleSegment.key.iv = iv;
     }
 
     if (segment.map) {
@@ -1136,6 +1177,11 @@ export default class SegmentLoader extends videojs.EventTarget {
       simpleSegment.map = this.initSegment(simpleSegment.map, true);
     }
 
+    // if this request included a segment key, save that data in the cache
+    if (simpleSegment.key) {
+      this.segmentKey(simpleSegment.key, true);
+    }
+
     this.processSegmentResponse_(simpleSegment);
   }
 

src/videojs-http-streaming.js

@@ -404,6 +404,7 @@ class HlsHandler extends Component {
         this.options_.useBandwidthFromLocalStorage || false;
     this.options_.customTagParsers = this.options_.customTagParsers || [];
     this.options_.customTagMappers = this.options_.customTagMappers || [];
+    this.options_.cacheEncryptionKeys = this.options_.cacheEncryptionKeys || false;
 
     if (typeof this.options_.blacklistDuration !== 'number') {
       this.options_.blacklistDuration = 5 * 60;
@@ -443,7 +444,8 @@ class HlsHandler extends Component {
       'smoothQualityChange',
       'customTagParsers',
       'customTagMappers',
-      'handleManifestRedirects'
+      'handleManifestRedirects',
+      'cacheEncryptionKeys'
     ].forEach((option) => {
       if (typeof this.source_[option] !== 'undefined') {
         this.options_[option] = this.source_[option];