Check for magnet links in watched folders.

Look for files ending with ".magnet" and interpret their contents as a
magnet link.
This allows scripts to collect magnet links from the web and let
qBittorrent download them non-interactively.

src/filesystemwatcher.h

@@ -22,6 +22,7 @@
 #endif
 
 #include "fs_utils.h"
+#include "misc.h"
 
 #ifndef CIFS_MAGIC_NUMBER
 #define CIFS_MAGIC_NUMBER 0xFF534D42
@@ -118,7 +119,7 @@ private:
 
 public:
   FileSystemWatcher(QObject *parent): QFileSystemWatcher(parent) {
-    m_filters << "*.torrent";
+    m_filters << "*.torrent" << "*.magnet";
     connect(this, SIGNAL(directoryChanged(QString)), this, SLOT(scanLocalFolder(QString)));
   }
 
@@ -271,7 +272,13 @@ private:
     const QStringList files = dir.entryList(m_filters, QDir::Files, QDir::Unsorted);
     foreach (const QString &file, files) {
       const QString file_abspath = dir.absoluteFilePath(file);
-      if (fsutils::isValidTorrentFile(file_abspath)) {
+      if (file_abspath.endsWith(".magnet")) {
+        QFile f(file_abspath);
+        if (f.open(QIODevice::ReadOnly)
+            && !misc::magnetUriToHash(QString::fromLocal8Bit(f.readAll())).isEmpty()) {
+          torrents << file_abspath;
+        }
+      } else if (fsutils::isValidTorrentFile(file_abspath)) {
         torrents << file_abspath;
       } else {
         if (!m_partialTorrents.contains(file_abspath)) {

src/qtlibtorrent/qbtsession.cpp

@@ -924,7 +924,7 @@ void QBtSession::loadTorrentSettings(QTorrentHandle& h) {
 #endif
 }
 
-QTorrentHandle QBtSession::addMagnetUri(QString magnet_uri, bool resumed) {
+QTorrentHandle QBtSession::addMagnetUri(QString magnet_uri, bool resumed, bool fromScanDir, const QString &filePath) {
   Preferences pref;
   QTorrentHandle h;
   const QString hash(misc::magnetUriToHash(magnet_uri));
@@ -952,7 +952,7 @@ QTorrentHandle QBtSession::addMagnetUri(QString magnet_uri, bool resumed) {
   add_torrent_params p = initializeAddTorrentParams(hash);
 
   // Get save path
-  const QString savePath(getSavePath(hash, false));
+  const QString savePath(getSavePath(hash, fromScanDir, filePath));
   if (!defaultTempPath.isEmpty() && !TorrentPersistentData::isSeed(hash) && resumed) {
     qDebug("addMagnetURI: Temp folder is enabled.");
     QString torrent_tmp_path = defaultTempPath.replace("\\", "/");
@@ -1742,6 +1742,17 @@ bool QBtSession::isFilePreviewPossible(const QString &hash) const {
 void QBtSession::addTorrentsFromScanFolder(QStringList &pathList) {
   foreach (const QString &file, pathList) {
     qDebug("File %s added", qPrintable(file));
+    if (file.endsWith(".magnet")) {
+      QFile f(file);
+      if (!f.open(QIODevice::ReadOnly)) {
+        qDebug("Failed to open magnet file: %s", qPrintable(f.errorString()));
+      } else {
+        const QString link = QString::fromLocal8Bit(f.readAll());
+        addMagnetUri(link, false, true, file);
+        f.remove();
+      }
+      continue;
+    }
     try {
       torrent_info t(file.toUtf8().constData());
       if (t.is_valid())

src/qtlibtorrent/qbtsession.h

@@ -105,7 +105,7 @@ public:
 
 public slots:
   QTorrentHandle addTorrent(QString path, bool fromScanDir = false, QString from_url = QString(), bool resumed = false);
-  QTorrentHandle addMagnetUri(QString magnet_uri, bool resumed=false);
+  QTorrentHandle addMagnetUri(QString magnet_uri, bool resumed=false, bool fromScanDir=false, const QString &filePath=QString());
   void loadSessionState();
   void saveSessionState();
   void downloadFromUrl(const QString &url, const QList<QNetworkCookie>& cookies = QList<QNetworkCookie>());