App stop responding some times , if SessionManager.fetchmagnet is called.

[mianharisali]

This is really weird behaviour , we have 2 apps based on Jlibtorrent. if we call SessionManager.fetchmagnet immediately after creating the session , the app stop responding. if we use the following code it works fine.

    private byte[] fetchMagnet(String uri)
    {
        final CountDownLatch signal = new CountDownLatch(1);

        final Timer timer = new Timer();
        timer.schedule(new TimerTask() {
            @Override
            public void run() {
                long nodes = torrentSession.stats().dhtNodes();
                // wait for at least 10 nodes in the DHT.
                if (nodes >= 10) {
                    System.out.println("DHT contains " + nodes + " nodes");
                    signal.countDown();
                    timer.cancel();
                }
            }
        }, 0, 1000);

        //System.out.println("Waiting for nodes in DHT (10 seconds)...");
        boolean r=false;

        try
        {
             r= signal.await(30, TimeUnit.SECONDS);
        }catch(Exception e)
        {

        }

        if (!r) {
            System.out.println("DHT bootstrap timeout");
            return null;
        }

        //System.out.println("Fetching the magnet uri, please wait...");
        byte[] data = torrentSession.fetchMagnet(uri, 30000);

        if (data != null) {
            return data;
            //System.out.println(Entry.bdecode(data));
        } else {
            return null;
            //System.out.println("Failed to retrieve the magnet");
        }
    }

[aldenml]

Is this torrentSession the same instance of SessionManager? Can you link me to reproducible small program that I can test?

[mianharisali]

yes , same instance. it occurs randomly , some time it works some time it stop responding. on our old app some users complained that app was stuck at getting metadata , and we were not able to find the issue , then when were developing our 2nd app , we encountered that issue.

we still cannot reproduce the issue , it occurs randomly. but i will try to reproduce it and send you sample.

[mianharisali]

@aldenml sorry for this issue , it seems it was my fault. i was calling fetch magnet with 30000 seconds timeout. and if there are no peers it was waiting for timeout and stopped fetching other magnets. 1 question , it seems like it can fetch 1 magnet at a moment , is it supposed to work this way.? because if 1 fetch 2 magnets it waits for the 1st one to be fetched and then fetches the 2nd one.

for now i use new session to fetch magnet and other for downloading. fetching in same session causes too many problems.

[aldenml]

I'm closing this issue because it's very old, but feel free to reopen if you can provide more info, you should be able to fetch more than one magnet at a time. Also, you may want to fine tune settings_pack.int_types.active_limit with a reasonable high value.