netneutrality/docs/reference/udio-lavalink-plugin/UdioAudioSourceManager.java

package me.bobert.netneutrality.music.source;
/*
 * Copyright (c) anthorob
 *
 * https://discord.gg/qUa6zNFZsd
 */

import com.sedmelluq.discord.lavaplayer.player.AudioPlayerManager;
import com.sedmelluq.discord.lavaplayer.source.AudioSourceManager;
import com.sedmelluq.discord.lavaplayer.tools.ExceptionTools;
import com.sedmelluq.discord.lavaplayer.tools.FriendlyException;
import com.sedmelluq.discord.lavaplayer.tools.JsonBrowser;
import com.sedmelluq.discord.lavaplayer.tools.io.HttpClientTools;
import com.sedmelluq.discord.lavaplayer.tools.io.HttpInterface;
import com.sedmelluq.discord.lavaplayer.tools.io.HttpInterfaceManager;
import com.sedmelluq.discord.lavaplayer.track.AudioItem;
import com.sedmelluq.discord.lavaplayer.track.AudioReference;
import com.sedmelluq.discord.lavaplayer.track.AudioTrack;
import com.sedmelluq.discord.lavaplayer.track.AudioTrackInfo;
import org.apache.commons.io.IOUtils;
import org.apache.http.HttpStatus;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpGet;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;

import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;
import java.nio.charset.StandardCharsets;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import static com.sedmelluq.discord.lavaplayer.tools.FriendlyException.Severity.SUSPICIOUS;

public class UdioAudioSourceManager implements AudioSourceManager {
    private static final Logger log = LogManager.getLogger(UdioAudioSourceManager.class);
    private static final String TRACK_URL_REGEX = "^https://www.udio.com/songs/[0-9A-Za-z]+$";
    private static final Pattern trackUrlPattern = Pattern.compile(TRACK_URL_REGEX);
    private static final Pattern NEXT_PUSH_PATTERN = Pattern.compile(
        "self\\.__next_f\\.push\\(\\[(\\d+),\"(.*?)\"]\\)",
        Pattern.DOTALL
    );
    private final HttpInterfaceManager httpInterfaceManager;

    public UdioAudioSourceManager() {
        httpInterfaceManager = HttpClientTools.createDefaultThreadLocalManager();
    }

    @Override
    public String getSourceName() {
        return "udio";
    }

    @Override
    public AudioItem loadItem(AudioPlayerManager manager, AudioReference reference) {
        if (!trackUrlPattern.matcher(reference.identifier).matches()) {
            return null;
        }

        try (HttpInterface httpInterface = httpInterfaceManager.getInterface()) {
            return loadFromTrackPage(httpInterface, reference.identifier);
        } catch (IOException e) {
            throw new FriendlyException("Loading Udio track information failed.", SUSPICIOUS, e);
        }
    }

    @Override
    public boolean isTrackEncodable(AudioTrack track) {
        return true;
    }

    @Override
    public void encodeTrack(AudioTrack track, DataOutput output) {

    }

    @Override
    public AudioTrack decodeTrack(AudioTrackInfo trackInfo, DataInput input) {
        return new UdioAudioTrack(trackInfo, this);
    }

    @Override
    public void shutdown() {
        ExceptionTools.closeWithWarnings(httpInterfaceManager);
    }

    public HttpInterface getHttpInterface() {
        return httpInterfaceManager.getInterface();
    }

    private AudioItem loadFromTrackPage(HttpInterface httpInterface, String trackUrl) throws IOException {
        try (CloseableHttpResponse response = httpInterface.execute(new HttpGet(trackUrl))) {
            int statusCode = response.getStatusLine().getStatusCode();

            if (statusCode == HttpStatus.SC_NOT_FOUND) {
                return AudioReference.NO_TRACK;
            } else if (!HttpClientTools.isSuccessWithContent(statusCode)) {
                throw new FriendlyException("Server responded with an error.", SUSPICIOUS,
                    new IllegalStateException("Response code is " + statusCode));
            }

            return loadTrackFromPageContent(trackUrl, IOUtils.toString(response.getEntity().getContent(), StandardCharsets.UTF_8));
        }
    }

    private AudioTrack loadTrackFromPageContent(String trackUrl, String content) throws IOException {
        JsonBrowser trackInfo = loadTrackInfoFromPageContent(content);

        if (trackInfo == null) {
            log.debug("Udio HTML: {}", content);
            throw new FriendlyException("Udio: Failed to extract track information from web page.", SUSPICIOUS, null);
        }

        String title = trackInfo.get("title").text();
        String artist = trackInfo.get("artist").text();
        long duration = (long) (trackInfo.get("duration").as(Double.class) * 1000.0);
        String playbackUrl = trackInfo.get("song_path").text();
        String artworkUrl = getArtworkUrlFromImagePath(trackInfo);

        AudioTrackInfo audioTrackInfo = new AudioTrackInfo(title, artist, duration, trackUrl, false, playbackUrl, artworkUrl, null);
        return new UdioAudioTrack(audioTrackInfo, this);
    }

    protected JsonBrowser loadTrackInfoFromPageContent(String content) throws IOException {
        Matcher matcher = NEXT_PUSH_PATTERN.matcher(content);
        while (matcher.find()) {
            String payload = matcher.group(2);
            JsonBrowser trackInfo = tryExtractTrackFromNextChunk(payload);

            if (trackInfo != null) {
                return trackInfo;
            }
        }

        return null;
    }

    private JsonBrowser tryExtractTrackFromNextChunk(String payload) {
        try {
            int trackKeyIndex = payload.indexOf("\\\"track\\\":{");
            if (trackKeyIndex < 0) {
                return null;
            }

            int objectStart = payload.indexOf('{', trackKeyIndex);
            if (objectStart < 0) {
                return null;
            }

            String escapedTrackJson = extractJsonObjectFromString(payload, objectStart);
            if (escapedTrackJson == null) {
                return null;
            }

            String trackJson = unescapeJsonStringFragment(escapedTrackJson);
            JsonBrowser track = JsonBrowser.parse(trackJson);

            if (isValidTrack(track)) {
                return track;
            }
        } catch (Exception e) {
            log.debug("Skipping unparsable track payload fragment", e);
        }

        return null;
    }

    /**
     * Extracts a JSON object from a given string starting at the specified index. This method parses the string
     * to locate and retrieve the JSON object, ensuring proper handling of nested structures and escaped characters.
     *
     * @param text The input string containing the JSON object to be extracted.
     * @param startIndex The index at which to start searching for the JSON object within the input string.
     * @return The extracted JSON object as a string, or {@code null} if no valid JSON object is found.
     */
    private String extractJsonObjectFromString(String text, int startIndex) {
        boolean escaped = false;
        boolean inString = false;
        int depth = 0;

        for (int i = startIndex; i < text.length(); i++) {
            char c = text.charAt(i);

            if (escaped) {
                escaped = false;
                continue;
            }

            if (c == '\\') {
                escaped = true;
                continue;
            }

            if (c == '"') {
                inString = !inString;
                continue;
            }

            if (inString) {
                continue;
            }

            if (c == '{') {
                depth++;
            } else if (c == '}') {
                depth--;
                if (depth == 0) {
                    return text.substring(startIndex, i + 1);
                }
            }
        }

        return null;
    }

    private String unescapeJsonStringFragment(String value) {
        return value.replace("\\\"", "\"").replace("\\\\", "\\");
    }

    private boolean isValidTrack(JsonBrowser track) {
        return track != null
            && !track.isNull()
            && !track.get("title").isNull()
            && !track.get("artist").isNull()
            && !track.get("duration").isNull()
            && !track.get("song_path").isNull()
            && !track.get("image_path").isNull();
    }

    private String getArtworkUrlFromImagePath(JsonBrowser trackInfo) {
        String imagePath = trackInfo.get("image_path").text();
        String artworkOptions = "width=3840,quality=75";

        return imagePath.replace("public", artworkOptions);
    }
}