LAMD/modules/m3u8stream/m3u8-parser.js

'use strict';

const Writable = require('stream').Writable;


/**
 * A very simple m3u8 playlist file parser that detects tags and segments.
 *
 * @extends WritableStream
 * @constructor
 */
module.exports = class m3u8parser extends Writable {
  constructor() {
    super({ decodeStrings: false });
    this._lastLine = '';
    this.on('finish', () => {
      this._parseLine(this._lastLine);
      this.emit('end');
    });
  }

  _parseLine(line) {
    var tag = line.match(/^#(EXT[A-Z0-9-]+)(?::(.*))?/);
    if (tag) {
      // This is a tag.
      this.emit('tag', tag[1], tag[2] || null);

    } else if (!/^#/.test(line) && line.trim()) {
      // This is a segment
      this.emit('item', line.trim());
    }
  }

  _write(chunk, encoding, callback) {
    var lines = chunk.toString('utf8').split('\n');
    if (this._lastLine) { lines[0] = this._lastLine + lines[0]; }
    lines.forEach((line, i) => {
      if (i < lines.length - 1) {
        this._parseLine(line);
      } else {
        // Save the last line in case it has been broken up.
        this._lastLine = line;
      }
    });
    callback();
  }
};