Download Reels From... IG ig?

InstaReelDownloader.java

import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.util.Optional;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

/**
 * Just give in two arguments, one for the page link and the other for the output file, as commandline arguments.
 * Wait until you see "Success!"
 */
class InstaReelDownloader {

    private static final Pattern pat = Pattern.compile("video_url\":\"([^\"]+)\"");

    private static Optional<byte[]> readAnd(String url_str) {
        try {
            URL url = new URL(url_str);
            try (InputStream ins = url.openStream()) {
                var bts = ins.readAllBytes();
                return Optional.of(bts);
            }
        } catch (Exception e) {
            System.out.println(e.getMessage());
        }
        return Optional.empty();
    }

    public static void main(String[] args) {
        if (args.length >= 1 && args[0].contains("?")) args[0] = args[0].substring(0, args[0].indexOf("?"));
        readAnd((args.length >= 1 ? args[0] : "https://www.instagram.com/tv/CeoZCGXAwcj/") + "?__a=1")
                .map(String::new)
                .map(pat::matcher)
                .filter(Matcher::find)
                .map(matcher -> matcher.group(1))
                .flatMap(Scratch::readAnd)
                .ifPresent(bytes -> {
                    try (var o = new FileOutputStream(args.length >= 2 ? args[1] : "D://out.mp4")) {
                        o.write(bytes);
                        System.out.println("Success!");
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                });
    }
}