Add WebAPI for fetching torrent metadata

src/base/bittorrent/torrentdescriptor.cpp

@@ -141,6 +141,22 @@ catch (const lt::system_error &err)
     return nonstd::make_unexpected(QString::fromLocal8Bit(err.what()));
 }
 
+nonstd::expected<QByteArray, QString> BitTorrent::TorrentDescriptor::saveToBuffer() const
+try
+{
+    const lt::entry torrentEntry = lt::write_torrent_file(m_ltAddTorrentParams);
+    // usually torrent size should be smaller than 1 MB,
+    // however there are >100 MB v2/hybrid torrent files out in the wild
+    QByteArray buffer;
+    buffer.reserve(1024 * 1024);
+    lt::bencode(std::back_inserter(buffer), torrentEntry);
+    return buffer;
+}
+catch (const lt::system_error &err)
+{
+    return nonstd::make_unexpected(QString::fromLocal8Bit(err.what()));
+}
+
 BitTorrent::TorrentDescriptor::TorrentDescriptor(lt::add_torrent_params ltAddTorrentParams)
     : m_ltAddTorrentParams {std::move(ltAddTorrentParams)}
 {

src/base/bittorrent/torrentdescriptor.h

@@ -69,6 +69,7 @@ namespace BitTorrent
         static nonstd::expected<TorrentDescriptor, QString> loadFromFile(const Path &path) noexcept;
         static nonstd::expected<TorrentDescriptor, QString> parse(const QString &str) noexcept;
         nonstd::expected<void, QString> saveToFile(const Path &path) const;
+        nonstd::expected<QByteArray, QString> saveToBuffer() const;
 
         const lt::add_torrent_params &ltAddTorrentParams() const;
 

src/webui/CMakeLists.txt

@@ -2,6 +2,7 @@ add_library(qbt_webui STATIC
     # headers
     api/apicontroller.h
     api/apierror.h
+    api/apistatus.h
     api/appcontroller.h
     api/authcontroller.h
     api/isessionmanager.h
@@ -14,6 +15,8 @@ add_library(qbt_webui STATIC
     api/transfercontroller.h
     api/serialize/serialize_torrent.h
     freediskspacechecker.h
+    torrentmetadatacache.h
+    torrentsourcecache.h
     webapplication.h
     webui.h
 
@@ -31,6 +34,8 @@ add_library(qbt_webui STATIC
     api/transfercontroller.cpp
     api/serialize/serialize_torrent.cpp
     freediskspacechecker.cpp
+    torrentmetadatacache.cpp
+    torrentsourcecache.cpp
     webapplication.cpp
     webui.cpp
 )

src/webui/api/apicontroller.cpp

@@ -42,6 +42,7 @@ void APIResult::clear()
     data.clear();
     mimeType.clear();
     filename.clear();
+    status = APIStatus::Ok;
 }
 
 APIController::APIController(IApplication *app, QObject *parent)
@@ -105,3 +106,8 @@ void APIController::setResult(const QByteArray &result, const QString &mimeType,
     m_result.mimeType = mimeType;
     m_result.filename = filename;
 }
+
+void APIController::setStatus(const APIStatus status)
+{
+    m_result.status = status;
+}

src/webui/api/apicontroller.h

@@ -34,6 +34,7 @@
 #include <QVariant>
 
 #include "base/applicationcomponent.h"
+#include "apistatus.h"
 
 using DataMap = QHash<QString, QByteArray>;
 using StringMap = QHash<QString, QString>;
@@ -43,6 +44,7 @@ struct APIResult
     QVariant data;
     QString mimeType;
     QString filename;
+    APIStatus status = APIStatus::Ok;
 
     void clear();
 };
@@ -67,6 +69,8 @@ class APIController : public ApplicationComponent<QObject>
     void setResult(const QJsonObject &result);
     void setResult(const QByteArray &result, const QString &mimeType = {}, const QString &filename = {});
 
+    void setStatus(APIStatus status);
+
 private:
     StringMap m_params;
     DataMap m_data;

src/webui/api/apistatus.h

@@ -0,0 +1,35 @@
+/*
+ * Bittorrent Client using Qt and libtorrent.
+ * Copyright (C) 2024 Thomas Piccirello <thomas@piccirello.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ *
+ * In addition, as a special exception, the copyright holders give permission to
+ * link this program with the OpenSSL project's "OpenSSL" library (or with
+ * modified versions of it that use the same license as the "OpenSSL" library),
+ * and distribute the linked executables. You must obey the GNU General Public
+ * License in all respects for all of the code used other than "OpenSSL".  If you
+ * modify file(s), you may extend this exception to your version of the file(s),
+ * but you are not obligated to do so. If you do not wish to do so, delete this
+ * exception statement from your version.
+ */
+
+#pragma once
+
+enum class APIStatus
+{
+    Ok,
+    Async
+};