shaka-player/lib/offline/offline_scheme.js

/**
 * @license
 * Copyright 2016 Google Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

goog.provide('shaka.offline.OfflineScheme');

goog.require('shaka.log');
goog.require('shaka.net.NetworkingEngine');
goog.require('shaka.offline.StorageEngineFactory');
goog.require('shaka.util.Error');


/**
 * @namespace
 * @summary A plugin that handles requests for offline content.
 * @param {string} uri
 * @param {shakaExtern.Request} request
 * @return {!Promise.<shakaExtern.Response>}
 * @export
 */
shaka.offline.OfflineScheme = function(uri, request) {
  var manifestId = shaka.offline.OfflineScheme.uriToManifestId(uri);
  if (manifestId != null) {
    return shaka.offline.OfflineScheme.onManifest_(uri);
  }

  var segmentId = shaka.offline.OfflineScheme.uriToSegmentId(uri);
  if (segmentId != null) {
    return shaka.offline.OfflineScheme.onSegment_(segmentId, uri);
  }

  return Promise.reject(new shaka.util.Error(
      shaka.util.Error.Severity.CRITICAL,
      shaka.util.Error.Category.NETWORK,
      shaka.util.Error.Code.MALFORMED_OFFLINE_URI,
      uri));
};


/**
 * @param {string} uri
 * @return {!Promise<shakaExtern.Response>}
 * @private
 */
shaka.offline.OfflineScheme.onManifest_ = function(uri) {
  /** @type {shakaExtern.Response} */
  var response = {
    uri: uri,
    data: new ArrayBuffer(0),
    headers: {'content-type': 'application/x-offline-manifest'}
  };

  return Promise.resolve(response);
};


/**
 * @param {number} id
 * @param {string} uri
 * @return {!Promise<shakaExtern.Response>}
 * @private
 */
shaka.offline.OfflineScheme.onSegment_ = function(id, uri) {
  /** @type {shaka.offline.IStorageEngine} */
  var storageEngine;
  var segment;

  return shaka.offline.StorageEngineFactory.createStorageEngine()
      .then(function(se) {
        storageEngine = se;
        return storageEngine.getSegment(id);
      })
      .then(function(seg) {
        segment = seg;
        return storageEngine.destroy();
      })
      .then(function() {
        if (!segment) {
          throw new shaka.util.Error(
              shaka.util.Error.Severity.CRITICAL,
              shaka.util.Error.Category.STORAGE,
              shaka.util.Error.Code.REQUESTED_ITEM_NOT_FOUND,
              id);
        }

        /** @type {shakaExtern.Response} */
        var response = {
          uri: uri,
          data: segment.data,
          headers: {}
        };

        return response;
      });
};


/**
 * @param {!number} id
 * @return {!string}
 */
shaka.offline.OfflineScheme.manifestIdToUri = function(id) {
  return 'offline:manifest/' + id;
};


/**
 * @param {!string} uri
 * @return {?number}
 */
shaka.offline.OfflineScheme.uriToManifestId = function(uri) {
  var parts = /^offline:manifest\/([0-9]+)$/.exec(uri);

  /** @type {?number} */
  var id = parts ? Number(parts[1]) : null;

  if (id != null) {
    return id;
  }

  // TODO (vaage) : Remove legacy support once database upgrades are supported.

  /** @type {?number} */
  var legacyId = shaka.offline.OfflineScheme.legacyUriToManifestId(uri);

  if (legacyId != null) {
    shaka.log.alwaysWarn(
        'Legacy uri detected. Download content again to update uris.');
  }

  return legacyId;
};


/**
 * @param {!string} uri
 * @return {?number}
 */
shaka.offline.OfflineScheme.legacyUriToManifestId = function(uri) {
  var parts = /^offline:([0-9]+)$/.exec(uri);
  return parts ? Number(parts[1]) : null;
};


/**
 * @param {number} id
 * @return {!string}
 */
shaka.offline.OfflineScheme.segmentIdToUri = function(id) {
  return 'offline:segment/' + id;
};


/**
 * @param {!string} uri
 * @return {?number}
 */
shaka.offline.OfflineScheme.uriToSegmentId = function(uri) {
  var parts = /^offline:segment\/([0-9]+)$/.exec(uri);

  /** @type {?number} */
  var id = parts ? Number(parts[1]) : null;

  if (id != null) {
    return id;
  }

  // TODO (vaage) : Remove legacy support once database upgrades are supported.

  /** @type {?number} */
  var legacyId = shaka.offline.OfflineScheme.legacyUriToSegmentId(uri);

  if (legacyId != null) {
    shaka.log.alwaysWarn(
        'Legacy uri detected. Download content again to update uris.');
  }

  return legacyId;
};


/**
 * @param {!string} uri
 * @return {?number}
 */
shaka.offline.OfflineScheme.legacyUriToSegmentId = function(uri) {
  var parts = /^offline:[0-9]+\/[0-9]+\/([0-9]+)$/.exec(uri);
  return parts ? Number(parts[1]) : null;
};


shaka.net.NetworkingEngine.registerScheme(
    'offline', shaka.offline.OfflineScheme);