youtube.ts•4.7 kB
import { spawnPromise } from 'spawn-rx';
import * as fs from 'node:fs';
import * as path from 'node:path';
import * as os from 'node:os';
import { rimraf } from 'rimraf';
export interface TranscriptOptions {
language?: string;
tempDir?: string;
}
export interface VideoMetadata {
title: string;
description: string;
}
export class YouTubeError extends Error {
constructor(message: string) {
super(message);
this.name = 'YouTubeError';
}
}
export async function getVideoMetadata(url: string): Promise<VideoMetadata> {
const args = [
'--skip-download',
'--print',
'%(title)s\n%(description)s',
url,
];
try {
const result = await spawnPromise('yt-dlp', args);
const [title, ...descriptionParts] = result.split('\n');
const description = descriptionParts.join('\n');
return {
title: title.trim(),
description: description.trim(),
};
} catch (error) {
if (error instanceof Error) {
throw new YouTubeError(`Failed to get video metadata: ${error.message}`);
}
throw error;
}
}
export async function getTranscript(
url: string,
options: TranscriptOptions = {}
): Promise<string> {
const tempDir =
options.tempDir || fs.mkdtempSync(path.join(os.tmpdir(), 'yt-'));
// Use video ID as filename to avoid "File name too long" errors
const shortFilenameTemplate = path.join(tempDir, '%(id)s.%(ext)s');
const args = [
'--write-sub',
'--write-auto-sub',
'--sub-lang',
options.language || 'ja',
'--skip-download',
'--sub-format',
'vtt',
'--output',
shortFilenameTemplate,
'--verbose',
url,
];
try {
await spawnPromise('yt-dlp', args);
const files = fs.readdirSync(tempDir);
const subtitleFiles = files.filter(
(file) => file.endsWith('.vtt') || file.endsWith('.srt')
);
if (subtitleFiles.length === 0) {
throw new YouTubeError('No transcript found for this video');
}
const content = fs.readFileSync(
path.join(tempDir, subtitleFiles[0]),
'utf8'
);
return cleanTranscript(content);
} catch (error) {
// Check if it's a filename length error and try fallback with even shorter name
if (error instanceof Error &&
(error.message.includes('File name too long') ||
error.message.includes('ENOENT') ||
error.message.includes('Errno 36'))) {
console.warn('Filename too long error detected, attempting fallback with timestamp-based filename');
// Fallback: Use timestamp-based filename
const timestamp = Date.now();
const fallbackTemplate = path.join(tempDir, `yt_${timestamp}.%(ext)s`);
const fallbackArgs = [...args];
const outputIndex = fallbackArgs.indexOf('--output');
if (outputIndex !== -1) {
fallbackArgs[outputIndex + 1] = fallbackTemplate;
}
try {
await spawnPromise('yt-dlp', fallbackArgs);
const files = fs.readdirSync(tempDir);
const subtitleFiles = files.filter(
(file) => file.endsWith('.vtt') || file.endsWith('.srt')
);
if (subtitleFiles.length === 0) {
throw new YouTubeError('No transcript found for this video (fallback attempt)');
}
const content = fs.readFileSync(
path.join(tempDir, subtitleFiles[0]),
'utf8'
);
return cleanTranscript(content);
} catch (fallbackError) {
if (fallbackError instanceof Error) {
throw new YouTubeError(`Failed to get transcript even with fallback filename: ${fallbackError.message}`);
}
throw fallbackError;
}
}
if (error instanceof Error) {
throw new YouTubeError(`Failed to get transcript: ${error.message}`);
}
throw error;
} finally {
if (!options.tempDir) {
rimraf.sync(tempDir);
}
}
}
function cleanTranscript(content: string): string {
const lines = content.split('\n');
let cleanedText = '';
let isSubtitleText = false;
const seenLines = new Set<string>();
for (const line of lines) {
const trimmedLine = line.trim();
if (/^\d+$/.test(trimmedLine)) {
continue;
}
if (trimmedLine.includes('-->')) {
isSubtitleText = true;
continue;
}
if (trimmedLine === '') {
isSubtitleText = false;
continue;
}
if (trimmedLine === 'WEBVTT') {
continue;
}
if (isSubtitleText) {
const cleanLine = trimmedLine.replace(/<[^>]*>/g, '').trim();
if (cleanLine && !seenLines.has(cleanLine)) {
cleanedText += `${cleanLine}\n`;
seenLines.add(cleanLine);
}
}
}
return cleanedText.trim();
}