68 lines
1.7 KiB
JavaScript
68 lines
1.7 KiB
JavaScript
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const Writable = require('stream').Writable;
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/**
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* A very simple m3u8 playlist file parser that detects tags and segments.
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*
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* @extends WritableStream
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* @constructor
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*/
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module.exports = class m3u8Parser extends Writable {
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constructor() {
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super();
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this._lastLine = '';
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this._seq = 0;
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this._nextItemDuration = null;
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this.on('finish', () => {
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this._parseLine(this._lastLine);
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this.emit('end');
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});
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}
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_parseLine(line) {
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let match = line.match(/^#(EXT[A-Z0-9-]+)(?::(.*))?/);
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if (match) {
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// This is a tag.
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const tag = match[1];
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const value = match[2] || null;
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switch (tag) {
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case 'EXT-X-PROGRAM-DATE-TIME':
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this.emit('starttime', new Date(value).getTime());
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break;
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case 'EXT-X-MEDIA-SEQUENCE':
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this._seq = parseInt(value, 10);
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break;
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case 'EXTINF':
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this._nextItemDuration =
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Math.round(parseFloat(value.split(',')[0], 10) * 1000);
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break;
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case 'EXT-X-ENDLIST':
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this.emit('endlist');
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break;
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}
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} else if (!/^#/.test(line) && line.trim()) {
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// This is a segment
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this.emit('item', {
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url: line.trim(),
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seq: this._seq++,
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duration: this._nextItemDuration,
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});
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}
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}
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_write(chunk, encoding, callback) {
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let lines = chunk.toString('utf8').split('\n');
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if (this._lastLine) { lines[0] = this._lastLine + lines[0]; }
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lines.forEach((line, i) => {
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if (i < lines.length - 1) {
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this._parseLine(line);
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} else {
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// Save the last line in case it has been broken up.
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this._lastLine = line;
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}
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});
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callback();
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}
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};
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