Support fetching tracker list from URL

Trackers specified at the URL will be added to newly added public torrents.

This feature is adapted from qBittorrent-Enhanced-Edition to allow for automatically adding trackers retrieved from a URL. @ngosang's trackerlist repo is a good example, however I've opted not to include a default URL.

Partially addresses #14535.
PR #21828.

src/base/bittorrent/session.h

@@ -237,6 +237,12 @@ namespace BitTorrent
         virtual Path finishedTorrentExportDirectory() const = 0;
         virtual void setFinishedTorrentExportDirectory(const Path &path) = 0;
 
+        virtual bool isAddTrackersFromURLEnabled() const = 0;
+        virtual void setAddTrackersFromURLEnabled(bool enabled) = 0;
+        virtual QString additionalTrackersURL() const = 0;
+        virtual void setAdditionalTrackersURL(const QString &url) = 0;
+        virtual QString additionalTrackersFromURL() const = 0;
+
         virtual int globalDownloadSpeedLimit() const = 0;
         virtual void setGlobalDownloadSpeedLimit(int limit) = 0;
         virtual int globalUploadSpeedLimit() const = 0;

src/base/bittorrent/sessionimpl.cpp

@@ -78,6 +78,7 @@
 #include "base/algorithm.h"
 #include "base/global.h"
 #include "base/logger.h"
+#include "base/net/downloadmanager.h"
 #include "base/net/proxyconfigurationmanager.h"
 #include "base/preferences.h"
 #include "base/profile.h"
@@ -463,6 +464,8 @@ SessionImpl::SessionImpl(QObject *parent)
     , m_blockPeersOnPrivilegedPorts(BITTORRENT_SESSION_KEY(u"BlockPeersOnPrivilegedPorts"_s), false)
     , m_isAddTrackersEnabled(BITTORRENT_SESSION_KEY(u"AddTrackersEnabled"_s), false)
     , m_additionalTrackers(BITTORRENT_SESSION_KEY(u"AdditionalTrackers"_s))
+    , m_isAddTrackersFromURLEnabled(BITTORRENT_SESSION_KEY(u"AddTrackersFromURLEnabled"_s), false)
+    , m_additionalTrackersURL(BITTORRENT_SESSION_KEY(u"AdditionalTrackersURL"_s))
     , m_globalMaxRatio(BITTORRENT_SESSION_KEY(u"GlobalMaxRatio"_s), -1, [](qreal r) { return r < 0 ? -1. : r;})
     , m_globalMaxSeedingMinutes(BITTORRENT_SESSION_KEY(u"GlobalMaxSeedingMinutes"_s), -1, lowerLimited(-1))
     , m_globalMaxInactiveSeedingMinutes(BITTORRENT_SESSION_KEY(u"GlobalMaxInactiveSeedingMinutes"_s), -1, lowerLimited(-1))
@@ -617,6 +620,15 @@ SessionImpl::SessionImpl(QObject *parent)
     enableTracker(isTrackerEnabled());
 
     prepareStartup();
+
+    m_updateTrackersFromURLTimer = new QTimer(this);
+    m_updateTrackersFromURLTimer->setInterval(24h);
+    connect(m_updateTrackersFromURLTimer, &QTimer::timeout, this, &SessionImpl::updateTrackersFromURL);
+    if (isAddTrackersFromURLEnabled())
+    {
+        updateTrackersFromURL();
+        m_updateTrackersFromURLTimer->start();
+    }
 }
 
 SessionImpl::~SessionImpl()
@@ -2268,6 +2280,11 @@ void SessionImpl::populateAdditionalTrackers()
     m_additionalTrackerEntries = parseTrackerEntries(additionalTrackers());
 }
 
+void SessionImpl::populateAdditionalTrackersFromURL()
+{
+    m_additionalTrackerEntriesFromURL = parseTrackerEntries(additionalTrackersFromURL());
+}
+
 void SessionImpl::processTorrentShareLimits(TorrentImpl *torrent)
 {
     if (!torrent->isFinished() || torrent->isForced())
@@ -2887,6 +2904,21 @@ bool SessionImpl::addTorrent_impl(const TorrentDescriptor &source, const AddTorr
         }
     }
 
+    if (isAddTrackersFromURLEnabled() && !(hasMetadata && p.ti->priv()))
+    {
+        const auto maxTierIter = std::max_element(p.tracker_tiers.cbegin(), p.tracker_tiers.cend());
+        const int baseTier = (maxTierIter != p.tracker_tiers.cend()) ? (*maxTierIter + 1) : 0;
+
+        p.trackers.reserve(p.trackers.size() + static_cast<std::size_t>(m_additionalTrackerEntriesFromURL.size()));
+        p.tracker_tiers.reserve(p.trackers.size() + static_cast<std::size_t>(m_additionalTrackerEntriesFromURL.size()));
+        p.tracker_tiers.resize(p.trackers.size(), 0);
+        for (const TrackerEntry &trackerEntry : asConst(m_additionalTrackerEntriesFromURL))
+        {
+            p.trackers.emplace_back(trackerEntry.url.toStdString());
+            p.tracker_tiers.emplace_back(Utils::Number::clampingAdd(trackerEntry.tier, baseTier));
+        }
+    }
+
     p.upload_limit = addTorrentParams.uploadLimit;
     p.download_limit = addTorrentParams.downloadLimit;
 
@@ -3879,6 +3911,82 @@ void SessionImpl::setAdditionalTrackers(const QString &trackers)
     populateAdditionalTrackers();
 }
 
+bool SessionImpl::isAddTrackersFromURLEnabled() const
+{
+    return m_isAddTrackersFromURLEnabled;
+}
+
+void SessionImpl::setAddTrackersFromURLEnabled(const bool enabled)
+{
+    if (enabled != isAddTrackersFromURLEnabled())
+    {
+        m_isAddTrackersFromURLEnabled = enabled;
+        if (enabled)
+        {
+            updateTrackersFromURL();
+            m_updateTrackersFromURLTimer->start();
+        }
+        else
+        {
+            m_updateTrackersFromURLTimer->stop();
+            setAdditionalTrackersFromURL({});
+        }
+    }
+}
+
+QString SessionImpl::additionalTrackersURL() const
+{
+    return m_additionalTrackersURL;
+}
+
+void SessionImpl::setAdditionalTrackersURL(const QString &url)
+{
+    if (url != additionalTrackersURL())
+    {
+        m_additionalTrackersURL = url.trimmed();
+        if (isAddTrackersFromURLEnabled())
+            updateTrackersFromURL();
+    }
+}
+
+QString SessionImpl::additionalTrackersFromURL() const
+{
+    return m_additionalTrackersFromURL;
+}
+
+void SessionImpl::setAdditionalTrackersFromURL(const QString &trackers)
+{
+    if (trackers != additionalTrackersFromURL())
+    {
+        m_additionalTrackersFromURL = trackers;
+        populateAdditionalTrackersFromURL();
+    }
+}
+
+void SessionImpl::updateTrackersFromURL()
+{
+    const QString url = additionalTrackersURL();
+    if (url.isEmpty())
+    {
+        setAdditionalTrackersFromURL({});
+    }
+    else
+    {
+        Net::DownloadManager::instance()->download(Net::DownloadRequest(url)
+                , Preferences::instance()->useProxyForGeneralPurposes(), this, [this](const Net::DownloadResult &result)
+        {
+            if (result.status == Net::DownloadStatus::Success)
+            {
+                setAdditionalTrackersFromURL(QString::fromUtf8(result.data));
+                LogMsg(tr("Tracker list updated"), Log::INFO);
+                return;
+            }
+
+            LogMsg(tr("Failed to update tracker list. Reason: \"%1\"").arg(result.errorString), Log::WARNING);
+        });
+    }
+}
+
 bool SessionImpl::isIPFilteringEnabled() const
 {
     return m_isIPFilteringEnabled;

src/base/bittorrent/sessionimpl.h

@@ -491,6 +491,12 @@ namespace BitTorrent
             m_asyncWorker->start(std::forward<Func>(func));
         }
 
+        bool isAddTrackersFromURLEnabled() const override;
+        void setAddTrackersFromURLEnabled(bool enabled) override;
+        QString additionalTrackersURL() const override;
+        void setAdditionalTrackersURL(const QString &url) override;
+        QString additionalTrackersFromURL() const override;
+
     signals:
         void addTorrentAlertsReceived(qsizetype count);
 
@@ -596,6 +602,8 @@ namespace BitTorrent
         void saveTorrentsQueue();
         void removeTorrentsQueue();
 
+        void populateAdditionalTrackersFromURL();
+
         std::vector<lt::alert *> getPendingAlerts(lt::time_duration time = lt::time_duration::zero()) const;
 
         void moveTorrentStorage(const MoveStorageJob &job) const;
@@ -614,6 +622,9 @@ namespace BitTorrent
 
         void handleRemovedTorrent(const TorrentID &torrentID, const QString &partfileRemoveError = {});
 
+        void setAdditionalTrackersFromURL(const QString &trackers);
+        void updateTrackersFromURL();
+
         CachedSettingValue<QString> m_DHTBootstrapNodes;
         CachedSettingValue<bool> m_isDHTEnabled;
         CachedSettingValue<bool> m_isLSDEnabled;
@@ -676,6 +687,8 @@ namespace BitTorrent
         CachedSettingValue<bool> m_blockPeersOnPrivilegedPorts;
         CachedSettingValue<bool> m_isAddTrackersEnabled;
         CachedSettingValue<QString> m_additionalTrackers;
+        CachedSettingValue<bool> m_isAddTrackersFromURLEnabled;
+        CachedSettingValue<QString> m_additionalTrackersURL;
         CachedSettingValue<qreal> m_globalMaxRatio;
         CachedSettingValue<int> m_globalMaxSeedingMinutes;
         CachedSettingValue<int> m_globalMaxInactiveSeedingMinutes;
@@ -749,6 +762,9 @@ namespace BitTorrent
         bool m_IPFilteringConfigured = false;
         mutable bool m_listenInterfaceConfigured = false;
 
+        QString m_additionalTrackersFromURL;
+        QTimer *m_updateTrackersFromURLTimer = nullptr;
+
         bool m_isRestored = false;
         bool m_isPaused = isStartPaused();
 
@@ -759,6 +775,7 @@ namespace BitTorrent
 
         int m_numResumeData = 0;
         QList<TrackerEntry> m_additionalTrackerEntries;
+        QList<TrackerEntry> m_additionalTrackerEntriesFromURL;
         QList<QRegularExpression> m_excludedFileNamesRegExpList;
 
         // Statistics

src/gui/optionsdialog.cpp

@@ -53,6 +53,7 @@
 #include "base/bittorrent/sharelimitaction.h"
 #include "base/exceptions.h"
 #include "base/global.h"
+#include "base/net/downloadmanager.h"
 #include "base/net/portforwarder.h"
 #include "base/net/proxyconfigurationmanager.h"
 #include "base/path.h"
@@ -1151,6 +1152,10 @@ void OptionsDialog::loadBittorrentTabOptions()
     m_ui->checkEnableAddTrackers->setChecked(session->isAddTrackersEnabled());
     m_ui->textTrackers->setPlainText(session->additionalTrackers());
 
+    m_ui->checkAddTrackersFromURL->setChecked(session->isAddTrackersFromURLEnabled());
+    m_ui->textTrackersURL->setText(session->additionalTrackersURL());
+    m_ui->textTrackersFromURL->setPlainText(session->additionalTrackersFromURL());
+
     connect(m_ui->checkDHT, &QAbstractButton::toggled, this, &ThisType::enableApplyButton);
     connect(m_ui->checkPeX, &QAbstractButton::toggled, this, &ThisType::enableApplyButton);
     connect(m_ui->checkLSD, &QAbstractButton::toggled, this, &ThisType::enableApplyButton);
@@ -1184,6 +1189,9 @@ void OptionsDialog::loadBittorrentTabOptions()
 
     connect(m_ui->checkEnableAddTrackers, &QGroupBox::toggled, this, &ThisType::enableApplyButton);
     connect(m_ui->textTrackers, &QPlainTextEdit::textChanged, this, &ThisType::enableApplyButton);
+
+    connect(m_ui->checkAddTrackersFromURL, &QGroupBox::toggled, this, &ThisType::enableApplyButton);
+    connect(m_ui->textTrackersURL, &QLineEdit::textChanged, this, &ThisType::enableApplyButton);
 }
 
 void OptionsDialog::saveBittorrentTabOptions() const
@@ -1221,6 +1229,9 @@ void OptionsDialog::saveBittorrentTabOptions() const
 
     session->setAddTrackersEnabled(m_ui->checkEnableAddTrackers->isChecked());
     session->setAdditionalTrackers(m_ui->textTrackers->toPlainText());
+
+    session->setAddTrackersFromURLEnabled(m_ui->checkAddTrackersFromURL->isChecked());
+    session->setAdditionalTrackersURL(m_ui->textTrackersURL->text());
 }
 
 void OptionsDialog::loadRSSTabOptions()

src/gui/optionsdialog.ui

@@ -3148,6 +3148,49 @@ Disable encryption: Only connect to peers without protocol encryption</string>
               </layout>
              </widget>
             </item>
+            <item>
+             <widget class="QGroupBox" name="checkAddTrackersFromURL">
+              <property name="title">
+               <string>Automatically append trackers from URL to new downloads:</string>
+              </property>
+              <property name="checkable">
+               <bool>true</bool>
+              </property>
+              <property name="checked">
+               <bool>false</bool>
+              </property>
+              <layout class="QVBoxLayout" name="checkAddTrackersFromURLLayout">
+               <item>
+                <layout class="QHBoxLayout" name="horizontalLayout_21">
+                 <item>
+                  <widget class="QLabel" name="labelCustomizeTrackersListUrl">
+                   <property name="text">
+                    <string>URL:</string>
+                   </property>
+                  </widget>
+                 </item>
+                 <item>
+                  <widget class="QLineEdit" name="textTrackersURL"/>
+                 </item>
+                </layout>
+               </item>
+               <item>
+                <widget class="QLabel" name="labeltrackersFromURL">
+                 <property name="text">
+                  <string>Fetched trackers</string>
+                 </property>
+                </widget>
+               </item>
+               <item>
+                <widget class="QPlainTextEdit" name="textTrackersFromURL">
+                 <property name="readOnly">
+                  <bool>true</bool>
+                 </property>
+                </widget>
+               </item>
+              </layout>
+             </widget>
+            </item>
             <item>
              <spacer name="verticalSpacer_8">
               <property name="orientation">

src/webui/api/appcontroller.cpp

@@ -307,6 +307,9 @@ void AppController::preferencesAction()
     // Add trackers
     data[u"add_trackers_enabled"_s] = session->isAddTrackersEnabled();
     data[u"add_trackers"_s] = session->additionalTrackers();
+    data[u"add_trackers_from_url_enabled"_s] = session->isAddTrackersFromURLEnabled();
+    data[u"add_trackers_url"_s] = session->additionalTrackersURL();
+    data[u"add_trackers_url_list"_s] = session->additionalTrackersFromURL();
 
     // WebUI
     // HTTP Server
@@ -863,6 +866,10 @@ void AppController::setPreferencesAction()
         session->setAddTrackersEnabled(it.value().toBool());
     if (hasKey(u"add_trackers"_s))
         session->setAdditionalTrackers(it.value().toString());
+    if (hasKey(u"add_trackers_from_url_enabled"_s))
+        session->setAddTrackersFromURLEnabled(it.value().toBool());
+    if (hasKey(u"add_trackers_url"_s))
+        session->setAdditionalTrackersURL(it.value().toString());
 
     // WebUI
     // HTTP Server

src/webui/www/private/views/preferences.html

@@ -825,6 +825,23 @@
         </legend>
         <textarea id="add_trackers_textarea" rows="5" cols="70" aria-labelledby="addTrackersLabel"></textarea>
     </fieldset>
+
+    <fieldset class="settings">
+        <legend>
+            <input type="checkbox" id="addTrackersFromURLCheckbox" onclick="qBittorrent.Preferences.updateAddTrackersFromURLEnabled();">
+            <label for="addTrackersFromURLCheckbox">QBT_TR(Automatically append trackers from URL to new downloads:)QBT_TR[CONTEXT=OptionsDialog]</label>
+        </legend>
+        <div class="formRow">
+            <label for="addTrackersURL">QBT_TR(URL:)QBT_TR[CONTEXT=OptionsDialog]</label>
+            <input type="text" id="addTrackersURL" style="width: 40em;">
+        </div>
+        <div class="formRow">
+            <fieldset class="settings">
+                <legend id="fetchedTrackersFromURLLabel">QBT_TR(Fetched trackers)QBT_TR[CONTEXT=OptionsDialog]</legend>
+                <textarea id="addTrackersURLListTextarea" aria-labelledby="fetchedTrackersFromURLLabel" rows="5" cols="70" readonly></textarea>
+            </fieldset>
+        </div>
+    </fieldset>
 </div>
 
 <div id="RSSTab" class="PrefTab invisible">
@@ -1736,6 +1753,7 @@ Use ';' to split multiple entries. Can use wildcard '*'.)QBT_TR[CONTEXT=OptionsD
                 updateSlowTorrentsSettings: updateSlowTorrentsSettings,
                 updateMaxRatioTimeEnabled: updateMaxRatioTimeEnabled,
                 updateAddTrackersEnabled: updateAddTrackersEnabled,
+                updateAddTrackersFromURLEnabled: updateAddTrackersFromURLEnabled,
                 updateHttpsSettings: updateHttpsSettings,
                 updateBypasssAuthSettings: updateBypasssAuthSettings,
                 updateAlternativeWebUISettings: updateAlternativeWebUISettings,
@@ -2016,6 +2034,11 @@ Use ';' to split multiple entries. Can use wildcard '*'.)QBT_TR[CONTEXT=OptionsD
             $("add_trackers_textarea").disabled = !isAddTrackersEnabled;
         };
 
+        const updateAddTrackersFromURLEnabled = () => {
+            const isAddTrackersFromURLEnabled = $("addTrackersFromURLCheckbox").checked;
+            $("addTrackersURL").disabled = !isAddTrackersFromURLEnabled;
+        };
+
         // WebUI tab
         const updateHttpsSettings = () => {
             const isUseHttpsEnabled = $("use_https_checkbox").checked;
@@ -2442,7 +2465,11 @@ Use ';' to split multiple entries. Can use wildcard '*'.)QBT_TR[CONTEXT=OptionsD
                     // Add trackers
                     $("add_trackers_checkbox").checked = pref.add_trackers_enabled;
                     $("add_trackers_textarea").value = pref.add_trackers;
+                    $("addTrackersFromURLCheckbox").checked = pref.add_trackers_from_url_enabled;
+                    $("addTrackersURLListTextarea").value = pref.add_trackers_url_list;
+                    $("addTrackersURL").value = pref.add_trackers_url;
                     updateAddTrackersEnabled();
+                    updateAddTrackersFromURLEnabled();
 
                     // RSS Tab
                     $("enable_fetching_rss_feeds_checkbox").checked = pref.rss_processing_enabled;
@@ -2876,6 +2903,8 @@ Use ';' to split multiple entries. Can use wildcard '*'.)QBT_TR[CONTEXT=OptionsD
             // Add trackers
             settings["add_trackers_enabled"] = $("add_trackers_checkbox").checked;
             settings["add_trackers"] = $("add_trackers_textarea").value;
+            settings["add_trackers_from_url_enabled"] = $("addTrackersFromURLCheckbox").checked;
+            settings["add_trackers_url"] = $("addTrackersURL").value;
 
             // RSS Tab
             settings["rss_processing_enabled"] = $("enable_fetching_rss_feeds_checkbox").checked;