parser.js 15.4 KB
'use strict';

Object.defineProperty(exports, "__esModule", {
  value: true
});

var _extends = Object.assign || function (target) { for (var i = 1; i < arguments.length; i++) { var source = arguments[i]; for (var key in source) { if (Object.prototype.hasOwnProperty.call(source, key)) { target[key] = source[key]; } } } return target; };

var _createClass = function () { function defineProperties(target, props) { for (var i = 0; i < props.length; i++) { var descriptor = props[i]; descriptor.enumerable = descriptor.enumerable || false; descriptor.configurable = true; if ("value" in descriptor) descriptor.writable = true; Object.defineProperty(target, descriptor.key, descriptor); } } return function (Constructor, protoProps, staticProps) { if (protoProps) defineProperties(Constructor.prototype, protoProps); if (staticProps) defineProperties(Constructor, staticProps); return Constructor; }; }();

var _stream = require('./stream');

var _stream2 = _interopRequireDefault(_stream);

var _lineStream = require('./line-stream');

var _lineStream2 = _interopRequireDefault(_lineStream);

var _parseStream = require('./parse-stream');

var _parseStream2 = _interopRequireDefault(_parseStream);

function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { 'default': obj }; }

function _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } }

function _possibleConstructorReturn(self, call) { if (!self) { throw new ReferenceError("this hasn't been initialised - super() hasn't been called"); } return call && (typeof call === "object" || typeof call === "function") ? call : self; }

function _inherits(subClass, superClass) { if (typeof superClass !== "function" && superClass !== null) { throw new TypeError("Super expression must either be null or a function, not " + typeof superClass); } subClass.prototype = Object.create(superClass && superClass.prototype, { constructor: { value: subClass, enumerable: false, writable: true, configurable: true } }); if (superClass) Object.setPrototypeOf ? Object.setPrototypeOf(subClass, superClass) : subClass.__proto__ = superClass; } /**
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                * @file m3u8/parser.js
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                */


/**
 * A parser for M3U8 files. The current interpretation of the input is
 * exposed as a property `manifest` on parser objects. It's just two lines to
 * create and parse a manifest once you have the contents available as a string:
 *
 * ```js
 * var parser = new m3u8.Parser();
 * parser.push(xhr.responseText);
 * ```
 *
 * New input can later be applied to update the manifest object by calling
 * `push` again.
 *
 * The parser attempts to create a usable manifest object even if the
 * underlying input is somewhat nonsensical. It emits `info` and `warning`
 * events during the parse if it encounters input that seems invalid or
 * requires some property of the manifest object to be defaulted.
 *
 * @class Parser
 * @extends Stream
 */
var Parser = function (_Stream) {
  _inherits(Parser, _Stream);

  function Parser() {
    _classCallCheck(this, Parser);

    var _this = _possibleConstructorReturn(this, (Parser.__proto__ || Object.getPrototypeOf(Parser)).call(this));

    _this.lineStream = new _lineStream2['default']();
    _this.parseStream = new _parseStream2['default']();
    _this.lineStream.pipe(_this.parseStream);
    /* eslint-disable consistent-this */
    var self = _this;
    /* eslint-enable consistent-this */
    var uris = [];
    var currentUri = {};
    // if specified, the active EXT-X-MAP definition
    var currentMap = void 0;
    // if specified, the active decryption key
    var _key = void 0;
    var noop = function noop() {};
    var defaultMediaGroups = {
      'AUDIO': {},
      'VIDEO': {},
      'CLOSED-CAPTIONS': {},
      'SUBTITLES': {}
    };
    // group segments into numbered timelines delineated by discontinuities
    var currentTimeline = 0;

    // the manifest is empty until the parse stream begins delivering data
    _this.manifest = {
      allowCache: true,
      discontinuityStarts: [],
      segments: []
    };

    // update the manifest with the m3u8 entry from the parse stream
    _this.parseStream.on('data', function (entry) {
      var mediaGroup = void 0;
      var rendition = void 0;

      ({
        tag: function tag() {
          // switch based on the tag type
          (({
            'allow-cache': function allowCache() {
              this.manifest.allowCache = entry.allowed;
              if (!('allowed' in entry)) {
                this.trigger('info', {
                  message: 'defaulting allowCache to YES'
                });
                this.manifest.allowCache = true;
              }
            },
            byterange: function byterange() {
              var byterange = {};

              if ('length' in entry) {
                currentUri.byterange = byterange;
                byterange.length = entry.length;

                if (!('offset' in entry)) {
                  this.trigger('info', {
                    message: 'defaulting offset to zero'
                  });
                  entry.offset = 0;
                }
              }
              if ('offset' in entry) {
                currentUri.byterange = byterange;
                byterange.offset = entry.offset;
              }
            },
            endlist: function endlist() {
              this.manifest.endList = true;
            },
            inf: function inf() {
              if (!('mediaSequence' in this.manifest)) {
                this.manifest.mediaSequence = 0;
                this.trigger('info', {
                  message: 'defaulting media sequence to zero'
                });
              }
              if (!('discontinuitySequence' in this.manifest)) {
                this.manifest.discontinuitySequence = 0;
                this.trigger('info', {
                  message: 'defaulting discontinuity sequence to zero'
                });
              }
              if (entry.duration > 0) {
                currentUri.duration = entry.duration;
              }

              if (entry.duration === 0) {
                currentUri.duration = 0.01;
                this.trigger('info', {
                  message: 'updating zero segment duration to a small value'
                });
              }

              this.manifest.segments = uris;
            },
            key: function key() {
              if (!entry.attributes) {
                this.trigger('warn', {
                  message: 'ignoring key declaration without attribute list'
                });
                return;
              }
              // clear the active encryption key
              if (entry.attributes.METHOD === 'NONE') {
                _key = null;
                return;
              }
              if (!entry.attributes.URI) {
                this.trigger('warn', {
                  message: 'ignoring key declaration without URI'
                });
                return;
              }
              if (!entry.attributes.METHOD) {
                this.trigger('warn', {
                  message: 'defaulting key method to AES-128'
                });
              }

              // setup an encryption key for upcoming segments
              _key = {
                method: entry.attributes.METHOD || 'AES-128',
                uri: entry.attributes.URI
              };

              if (typeof entry.attributes.IV !== 'undefined') {
                _key.iv = entry.attributes.IV;
              }
            },
            'media-sequence': function mediaSequence() {
              if (!isFinite(entry.number)) {
                this.trigger('warn', {
                  message: 'ignoring invalid media sequence: ' + entry.number
                });
                return;
              }
              this.manifest.mediaSequence = entry.number;
            },
            'discontinuity-sequence': function discontinuitySequence() {
              if (!isFinite(entry.number)) {
                this.trigger('warn', {
                  message: 'ignoring invalid discontinuity sequence: ' + entry.number
                });
                return;
              }
              this.manifest.discontinuitySequence = entry.number;
              currentTimeline = entry.number;
            },
            'playlist-type': function playlistType() {
              if (!/VOD|EVENT/.test(entry.playlistType)) {
                this.trigger('warn', {
                  message: 'ignoring unknown playlist type: ' + entry.playlist
                });
                return;
              }
              this.manifest.playlistType = entry.playlistType;
            },
            map: function map() {
              currentMap = {};
              if (entry.uri) {
                currentMap.uri = entry.uri;
              }
              if (entry.byterange) {
                currentMap.byterange = entry.byterange;
              }
            },
            'stream-inf': function streamInf() {
              this.manifest.playlists = uris;
              this.manifest.mediaGroups = this.manifest.mediaGroups || defaultMediaGroups;

              if (!entry.attributes) {
                this.trigger('warn', {
                  message: 'ignoring empty stream-inf attributes'
                });
                return;
              }

              if (!currentUri.attributes) {
                currentUri.attributes = {};
              }
              _extends(currentUri.attributes, entry.attributes);
            },
            media: function media() {
              this.manifest.mediaGroups = this.manifest.mediaGroups || defaultMediaGroups;

              if (!(entry.attributes && entry.attributes.TYPE && entry.attributes['GROUP-ID'] && entry.attributes.NAME)) {
                this.trigger('warn', {
                  message: 'ignoring incomplete or missing media group'
                });
                return;
              }

              // find the media group, creating defaults as necessary
              var mediaGroupType = this.manifest.mediaGroups[entry.attributes.TYPE];

              mediaGroupType[entry.attributes['GROUP-ID']] = mediaGroupType[entry.attributes['GROUP-ID']] || {};
              mediaGroup = mediaGroupType[entry.attributes['GROUP-ID']];

              // collect the rendition metadata
              rendition = {
                'default': /yes/i.test(entry.attributes.DEFAULT)
              };
              if (rendition['default']) {
                rendition.autoselect = true;
              } else {
                rendition.autoselect = /yes/i.test(entry.attributes.AUTOSELECT);
              }
              if (entry.attributes.LANGUAGE) {
                rendition.language = entry.attributes.LANGUAGE;
              }
              if (entry.attributes.URI) {
                rendition.uri = entry.attributes.URI;
              }
              if (entry.attributes['INSTREAM-ID']) {
                rendition.instreamId = entry.attributes['INSTREAM-ID'];
              }
              if (entry.attributes.CHARACTERISTICS) {
                rendition.characteristics = entry.attributes.CHARACTERISTICS;
              }
              if (entry.attributes.FORCED) {
                rendition.forced = /yes/i.test(entry.attributes.FORCED);
              }

              // insert the new rendition
              mediaGroup[entry.attributes.NAME] = rendition;
            },
            discontinuity: function discontinuity() {
              currentTimeline += 1;
              currentUri.discontinuity = true;
              this.manifest.discontinuityStarts.push(uris.length);
            },
            'program-date-time': function programDateTime() {
              this.manifest.dateTimeString = entry.dateTimeString;
              this.manifest.dateTimeObject = entry.dateTimeObject;
            },
            targetduration: function targetduration() {
              if (!isFinite(entry.duration) || entry.duration < 0) {
                this.trigger('warn', {
                  message: 'ignoring invalid target duration: ' + entry.duration
                });
                return;
              }
              this.manifest.targetDuration = entry.duration;
            },
            totalduration: function totalduration() {
              if (!isFinite(entry.duration) || entry.duration < 0) {
                this.trigger('warn', {
                  message: 'ignoring invalid total duration: ' + entry.duration
                });
                return;
              }
              this.manifest.totalDuration = entry.duration;
            },
            'cue-out': function cueOut() {
              currentUri.cueOut = entry.data;
            },
            'cue-out-cont': function cueOutCont() {
              currentUri.cueOutCont = entry.data;
            },
            'cue-in': function cueIn() {
              currentUri.cueIn = entry.data;
            }
          })[entry.tagType] || noop).call(self);
        },
        uri: function uri() {
          currentUri.uri = entry.uri;
          uris.push(currentUri);

          // if no explicit duration was declared, use the target duration
          if (this.manifest.targetDuration && !('duration' in currentUri)) {
            this.trigger('warn', {
              message: 'defaulting segment duration to the target duration'
            });
            currentUri.duration = this.manifest.targetDuration;
          }
          // annotate with encryption information, if necessary
          if (_key) {
            currentUri.key = _key;
          }
          currentUri.timeline = currentTimeline;
          // annotate with initialization segment information, if necessary
          if (currentMap) {
            currentUri.map = currentMap;
          }

          // prepare for the next URI
          currentUri = {};
        },
        comment: function comment() {
          // comments are not important for playback
        }
      })[entry.type].call(self);
    });

    return _this;
  }

  /**
   * Parse the input string and update the manifest object.
   *
   * @param {String} chunk a potentially incomplete portion of the manifest
   */


  _createClass(Parser, [{
    key: 'push',
    value: function push(chunk) {
      this.lineStream.push(chunk);
    }

    /**
     * Flush any remaining input. This can be handy if the last line of an M3U8
     * manifest did not contain a trailing newline but the file has been
     * completely received.
     */

  }, {
    key: 'end',
    value: function end() {
      // flush any buffered input
      this.lineStream.push('\n');
    }
  }]);

  return Parser;
}(_stream2['default']);

exports['default'] = Parser;