- Qt 5.5
- Qt Network
- Torrent Example
- trackerclient.cpp Example File
- Qt 5.5.1 Reference Documentation

# trackerclient.cpp Example File

torrent/trackerclient.cpp

    /****************************************************************************
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    ** Contact: http://www.qt.io/licensing/
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    ** This file is part of the examples of the Qt Toolkit.
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    ** $QT_BEGIN_LICENSE:BSD$
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    #include "bencodeparser.h"
    #include "connectionmanager.h"
    #include "torrentclient.h"
    #include "torrentserver.h"
    #include "trackerclient.h"

    #include <QtCore>
    #include <QNetworkRequest>

    TrackerClient::TrackerClient(TorrentClient *downloader, QObject *parent)
        : QObject(parent), torrentDownloader(downloader)
    {
        length = 0;
        requestInterval = 5 * 60;
        requestIntervalTimer = -1;
        firstTrackerRequest = true;
        lastTrackerRequest = false;
        firstSeeding = true;

        connect(&http, SIGNAL(finished(QNetworkReply*)), this, SLOT(httpRequestDone(QNetworkReply*)));
    }

    void TrackerClient::start(const MetaInfo &info)
    {
        metaInfo = info;
        QTimer::singleShot(0, this, SLOT(fetchPeerList()));

        if (metaInfo.fileForm() == MetaInfo::SingleFileForm) {
            length = metaInfo.singleFile().length;
        } else {
            QList<MetaInfoMultiFile> files = metaInfo.multiFiles();
            for (int i = 0; i < files.size(); ++i)
                length += files.at(i).length;
        }
    }

    void TrackerClient::startSeeding()
    {
        firstSeeding = true;
        fetchPeerList();
    }

    void TrackerClient::stop()
    {
        lastTrackerRequest = true;
        fetchPeerList();
    }

    void TrackerClient::timerEvent(QTimerEvent *event)
    {
        if (event->timerId() == requestIntervalTimer) {
            fetchPeerList();
        } else {
            QObject::timerEvent(event);
        }
    }

    void TrackerClient::fetchPeerList()
    {
        QUrl url(metaInfo.announceUrl());

        // Base the query on announce url to include a passkey (if any)
        QUrlQuery query(url);

        // Percent encode the hash
        QByteArray infoHash = torrentDownloader->infoHash();
        QByteArray encodedSum;
        for (int i = 0; i < infoHash.size(); ++i) {
            encodedSum += '%';
            encodedSum += QByteArray::number(infoHash[i], 16).right(2).rightJustified(2, '0');
        }

        bool seeding = (torrentDownloader->state() == TorrentClient::Seeding);

        query.addQueryItem("info_hash", encodedSum);
        query.addQueryItem("peer_id", ConnectionManager::instance()->clientId());
        query.addQueryItem("port", QByteArray::number(TorrentServer::instance()->serverPort()));
        query.addQueryItem("compact", "1");
        query.addQueryItem("uploaded", QByteArray::number(torrentDownloader->uploadedBytes()));

        if (!firstSeeding) {
            query.addQueryItem("downloaded", "0");
            query.addQueryItem("left", "0");
        } else {
            query.addQueryItem("downloaded",
                               QByteArray::number(torrentDownloader->downloadedBytes()));
            int left = qMax<int>(0, metaInfo.totalSize() - torrentDownloader->downloadedBytes());
            query.addQueryItem("left", QByteArray::number(seeding ? 0 : left));
        }

        if (seeding && firstSeeding) {
            query.addQueryItem("event", "completed");
            firstSeeding = false;
        } else if (firstTrackerRequest) {
            firstTrackerRequest = false;
            query.addQueryItem("event", "started");
        } else if(lastTrackerRequest) {
            query.addQueryItem("event", "stopped");
        }

        if (!trackerId.isEmpty())
            query.addQueryItem("trackerid", trackerId);

        url.setQuery(query);

        QNetworkRequest req(url);
        if (!url.userName().isEmpty()) {
            uname = url.userName();
            pwd = url.password();
            connect(&http, SIGNAL(authenticationRequired(QNetworkReply*,QAuthenticator*)),
                    this, SLOT(provideAuthentication(QNetworkReply*,QAuthenticator*)));
        }
        http.get(req);
    }

    void TrackerClient::httpRequestDone(QNetworkReply *reply)
    {
        reply->deleteLater();
        if (lastTrackerRequest) {
            emit stopped();
            return;
        }

        if (reply->error() != QNetworkReply::NoError) {
            emit connectionError(reply->error());
            return;
        }

        QByteArray response = reply->readAll();
        reply->abort();

        BencodeParser parser;
        if (!parser.parse(response)) {
            qWarning("Error parsing bencode response from tracker: %s",
                     qPrintable(parser.errorString()));
            return;
        }

        QMap<QByteArray, QVariant> dict = parser.dictionary();

        if (dict.contains("failure reason")) {
            // no other items are present
            emit failure(QString::fromUtf8(dict.value("failure reason").toByteArray()));
            return;
        }

        if (dict.contains("warning message")) {
            // continue processing
            emit warning(QString::fromUtf8(dict.value("warning message").toByteArray()));
        }

        if (dict.contains("tracker id")) {
            // store it
            trackerId = dict.value("tracker id").toByteArray();
        }

        if (dict.contains("interval")) {
            // Mandatory item
            if (requestIntervalTimer != -1)
                killTimer(requestIntervalTimer);
            requestIntervalTimer = startTimer(dict.value("interval").toInt() * 1000);
        }

        if (dict.contains("peers")) {
            // store it
            peers.clear();
            QVariant peerEntry = dict.value("peers");
            if (peerEntry.type() == QVariant::List) {
                QList<QVariant> peerTmp = peerEntry.toList();
                for (int i = 0; i < peerTmp.size(); ++i) {
                    TorrentPeer tmp;
                    QMap<QByteArray, QVariant> peer = qvariant_cast<QMap<QByteArray, QVariant> >(peerTmp.at(i));
                    tmp.id = QString::fromUtf8(peer.value("peer id").toByteArray());
                    tmp.address.setAddress(QString::fromUtf8(peer.value("ip").toByteArray()));
                    tmp.port = peer.value("port").toInt();
                    peers << tmp;
                }
            } else {
                QByteArray peerTmp = peerEntry.toByteArray();
                for (int i = 0; i < peerTmp.size(); i += 6) {
                    TorrentPeer tmp;
                    uchar *data = (uchar *)peerTmp.constData() + i;
                    tmp.port = (int(data[4]) << 8) + data[5];
                    uint ipAddress = 0;
                    ipAddress += uint(data[0]) << 24;
                    ipAddress += uint(data[1]) << 16;
                    ipAddress += uint(data[2]) << 8;
                    ipAddress += uint(data[3]);
                    tmp.address.setAddress(ipAddress);
                    peers << tmp;
                }
            }
            emit peerListUpdated(peers);
        }
    }

    void TrackerClient::provideAuthentication(QNetworkReply *reply, QAuthenticator *auth)
    {
        Q_UNUSED(reply);
        auth->setUser(uname);
        auth->setPassword(pwd);
    }