import { decipherFormatURLs } from "./decipher.ts";import { Format, VideoInfo } from "./types.ts";
export const BASE_URL = "https://www.youtube.com/watch?v=";const USER_AGENT = "Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:107.0) Gecko/20100101 Firefox/107.0";
export async function ytDownload( id: string, options: Options = { hasAudio: true, hasVideo: true }) { const formats = await getFormats(id, options); if (formats.length === 0) { throw "No matching formats found"; } return getDataStream(formats[0]);}
export async function getVideoInfo(id: string): Promise<undefined | VideoInfo> { try { const url = `${BASE_URL}${id}&hl=en`; const resp = await fetch(url, { headers: { "User-Agent": USER_AGENT, }, }); const html = await resp.text(); const responses = html.match( /ytInitialPlayerResponse = ([\S\s]+)?(?=;var meta)/ ); const playerInfo = JSON.parse(responses![1]); const playerURL = html.match(/"jsUrl":"([^"]+)"/)![1]; await decipherFormatURLs(playerInfo, playerURL); return playerInfo; } catch { return undefined; }}
type Options = { hasVideo?: boolean; hasAudio?: boolean; mimeType?: string;};
export async function getFormats( id: string, { hasAudio, hasVideo, mimeType }: Options = {}) { const info = await getVideoInfo(id); if (info === undefined) { throw "Video not found"; } const result = [ ...info.streamingData.adaptiveFormats, ...info.streamingData.formats, ]; result.sort((a, b) => b.bitrate - a.bitrate); return result .filter( (format) => hasAudio === undefined || (hasAudio && format.audioQuality !== undefined) || (!hasAudio && format.audioQuality === undefined) ) .filter( (format) => hasVideo === undefined || (hasVideo && format.qualityLabel !== undefined) || (!hasVideo && format.qualityLabel === undefined) ) .filter((format) => mimeType === undefined || mimeType === format.mimeType);}
export async function getDataStream(format: Format) { return (await fetch(format.url)).body!;}