Source: lib/mss/content_protection.js

  1. /*! @license
  2.  * Shaka Player
  3.  * Copyright 2016 Google LLC
  4.  * SPDX-License-Identifier: Apache-2.0
  5.  */
  7. goog.provide('shaka.mss.ContentProtection');
  9. goog.require('shaka.drm.PlayReady');
  10. goog.require('shaka.util.ManifestParserUtils');
  11. goog.require('shaka.util.Pssh');
  12. goog.require('shaka.util.TXml');
  13. goog.require('shaka.util.Uint8ArrayUtils');
  16. /**
  17.  * @summary A set of functions for parsing and interpreting Protection
  18.  *   elements.
  19.  */
  20. shaka.mss.ContentProtection = class {
  21.   /**
  22.    * Parses info from the Protection elements.
  23.    *
  24.    * @param {!Array<!shaka.extern.xml.Node>} elements
  25.    * @param {!Object<string, string>} keySystemsBySystemId
  26.    * @return {!Array<shaka.extern.DrmInfo>}
  27.    */
  28.   static parseFromProtection(elements, keySystemsBySystemId) {
  29.     const ContentProtection = shaka.mss.ContentProtection;
  30.     const TXml = shaka.util.TXml;
  32.     /** @type {!Array<!shaka.extern.xml.Node>} */
  33.     let protectionHeader = [];
  34.     for (const element of elements) {
  35.       protectionHeader = protectionHeader.concat(
  36.           TXml.findChildren(element, 'ProtectionHeader'));
  37.     }
  38.     if (!protectionHeader.length) {
  39.       return [];
  40.     }
  41.     return ContentProtection.convertElements_(
  42.         protectionHeader, keySystemsBySystemId);
  43.   }
  45.   /**
  46.    * Gets a PlayReady license URL from a protection element
  47.    * containing a PlayReady Header Object
  48.    *
  49.    * @param {!shaka.extern.xml.Node} element
  50.    * @return {string}
  51.    */
  52.   static getPlayReadyLicenseUrl(element) {
  53.     return shaka.drm.PlayReady.getLicenseUrl(element);
  54.   }
  56.   /**
  57.    * Gets a PlayReady KID from a protection element
  58.    * containing a PlayReady Header Object
  59.    *
  60.    * @param {!shaka.extern.xml.Node} element
  61.    * @return {?string}
  62.    * @private
  63.    */
  64.   static getPlayReadyKID_(element) {
  65.     return shaka.drm.PlayReady.getPlayReadyKID(element);
  66.   }
  68.   /**
  69.    * Gets a initData from a protection element.
  70.    *
  71.    * @param {!shaka.extern.xml.Node} element
  72.    * @param {string} systemID
  73.    * @param {?string} keyId
  74.    * @return {?Array<shaka.extern.InitDataOverride>}
  75.    * @private
  76.    */
  77.   static getInitDataFromPro_(element, systemID, keyId) {
  78.     const Uint8ArrayUtils = shaka.util.Uint8ArrayUtils;
  79.     const data = Uint8ArrayUtils.fromBase64(
  80.         /** @type {string} */ (shaka.util.TXml.getTextContents(element)));
  81.     const systemId = Uint8ArrayUtils.fromHex(systemID.replace(/-/g, ''));
  82.     const keyIds = new Set();
  83.     const psshVersion = 0;
  84.     const pssh =
  85.         shaka.util.Pssh.createPssh(data, systemId, keyIds, psshVersion);
  86.     return [
  87.       {
  88.         initData: pssh,
  89.         initDataType: 'cenc',
  90.         keyId: keyId,
  91.       },
  92.     ];
  93.   }
  95.   /**
  96.    * Creates DrmInfo objects from an array of elements.
  97.    *
  98.    * @param {!Array<!shaka.extern.xml.Node>} elements
  99.    * @param {!Object<string, string>} keySystemsBySystemId
  100.    * @return {!Array<shaka.extern.DrmInfo>}
  101.    * @private
  102.    */
  103.   static convertElements_(elements, keySystemsBySystemId) {
  104.     const ContentProtection = shaka.mss.ContentProtection;
  105.     const ManifestParserUtils = shaka.util.ManifestParserUtils;
  106.     const licenseUrlParsers = ContentProtection.licenseUrlParsers_;
  108.     /** @type {!Array<shaka.extern.DrmInfo>} */
  109.     const out = [];
  111.     for (let i = 0; i < elements.length; i++) {
  112.       const element = elements[i];
  113.       const systemID = element.attributes['SystemID'].toLowerCase();
  114.       const keySystem = keySystemsBySystemId[systemID];
  115.       if (keySystem) {
  116.         const KID = ContentProtection.getPlayReadyKID_(element);
  117.         const initData = ContentProtection.getInitDataFromPro_(
  118.             element, systemID, KID);
  120.         const info = ManifestParserUtils.createDrmInfo(
  121.             keySystem, /* encryptionScheme= */ 'cenc', initData);
  122.         if (KID) {
  123.           info.keyIds.add(KID);
  124.         }
  126.         const licenseParser = licenseUrlParsers.get(keySystem);
  127.         if (licenseParser) {
  128.           info.licenseServerUri = licenseParser(element);
  129.         }
  131.         out.push(info);
  132.       }
  133.     }
  135.     return out;
  136.   }
  137. };
  139. /**
  140.  * A map of key system name to license server url parser.
  141.  *
  142.  * @const {!Map<string, function(!shaka.extern.xml.Node)>}
  143.  * @private
  144.  */
  145. shaka.mss.ContentProtection.licenseUrlParsers_ = new Map()
  146.     .set('com.microsoft.playready',
  147.         shaka.mss.ContentProtection.getPlayReadyLicenseUrl)
  148.     .set('com.microsoft.playready.recommendation',
  149.         shaka.mss.ContentProtection.getPlayReadyLicenseUrl)
  150.     .set('com.microsoft.playready.software',
  151.         shaka.mss.ContentProtection.getPlayReadyLicenseUrl)
  152.     .set('com.microsoft.playready.hardware',
  153.         shaka.mss.ContentProtection.getPlayReadyLicenseUrl);