cobalt/src/modules/processing/services/vk.js

import { xml2json } from "xml-js";
import { genericUserAgent, maxVideoDuration, services } from "../../config.js";
import selectQuality from "../../stream/selectQuality.js";

export default async function(obj) {
    let html;
    html = await fetch(`https://vk.com/video-${obj.userId}_${obj.videoId}`, {
        headers: { "user-agent": genericUserAgent }
    }).then((r) => { return r.text() }).catch(() => { return false });
    if (!html) return { error: 'ErrorCouldntFetch' };
    if (!html.includes(`{"lang":`)) return { error: 'ErrorEmptyDownload' };

    let js = JSON.parse('{"lang":' + html.split(`{"lang":`)[1].split(']);')[0]);

    if (Number(js["mvData"]["is_active_live"]) !== 0) return { error: 'ErrorLiveVideo' };
    if (js["mvData"]["duration"] > maxVideoDuration / 1000) return { error: ['ErrorLengthLimit', maxVideoDuration / 60000] };

    let mpd = JSON.parse(xml2json(js["player"]["params"][0]["manifest"], { compact: true, spaces: 4 }));
    let repr = mpd["MPD"]["Period"]["AdaptationSet"]["Representation"];
    if (!mpd["MPD"]["Period"]["AdaptationSet"]["Representation"]) repr = mpd["MPD"]["Period"]["AdaptationSet"][0]["Representation"];

    let selectedQuality,
        attr = repr[repr.length - 1]["_attributes"], 
        qualities = Object.keys(services.vk.quality_match);
    for (let i in qualities) {
        if (qualities[i] === attr["height"]) {
            selectedQuality = `url${attr["height"]}`;
            break
        }
        if (qualities[i] === attr["width"]) {
            selectedQuality = `url${attr["width"]}`;
            break
        }
    }

    let maxQuality = js["player"]["params"][0][selectedQuality].split('type=')[1].slice(0, 1);
    let userQuality = selectQuality('vk', obj.quality, Object.entries(services.vk.quality_match).reduce((r, [k, v]) => { r[v] = k; return r; })[maxQuality]);
    let userRepr = repr[services.vk.representation_match[userQuality]]["_attributes"];
    if (!(selectedQuality in js["player"]["params"][0])) return { error: 'ErrorEmptyDownload' };

    return {
        urls: js["player"]["params"][0][`url${userQuality}`],
        filename: `vk_${obj.userId}_${obj.videoId}_${userRepr["width"]}x${userRepr['height']}.mp4`
    }
}