WebAPI: Support persisting WebUI client data

WebAPI_Changelog.md

@@ -4,6 +4,8 @@
 * [#23163](https://github.com/qbittorrent/qBittorrent/pull/23163)
   * `torrents/add` endpoint now supports downloading from a search plugin via the `downloader` parameter
   * `torrents/fetchMetadata` endpoint now supports fetching from a search plugin via the `downloader` parameter
+* [#23088](https://github.com/qbittorrent/qBittorrent/pull/23088)
+  * Add `clientdata/load` and `clientdata/store` endpoints for managing WebUI-specific client settings and other shared data
 
 ## 2.13.0
 * [#23045](https://github.com/qbittorrent/qBittorrent/pull/23045)

src/webui/CMakeLists.txt

@@ -5,6 +5,7 @@ add_library(qbt_webui STATIC
     api/apistatus.h
     api/appcontroller.h
     api/authcontroller.h
+    api/clientdatacontroller.h
     api/isessionmanager.h
     api/logcontroller.h
     api/rsscontroller.h
@@ -14,6 +15,7 @@ add_library(qbt_webui STATIC
     api/torrentscontroller.h
     api/transfercontroller.h
     api/serialize/serialize_torrent.h
+    clientdatastorage.h
     webapplication.h
     webui.h
 
@@ -22,6 +24,7 @@ add_library(qbt_webui STATIC
     api/apierror.cpp
     api/appcontroller.cpp
     api/authcontroller.cpp
+    api/clientdatacontroller.cpp
     api/logcontroller.cpp
     api/rsscontroller.cpp
     api/searchcontroller.cpp
@@ -30,6 +33,7 @@ add_library(qbt_webui STATIC
     api/torrentscontroller.cpp
     api/transfercontroller.cpp
     api/serialize/serialize_torrent.cpp
+    clientdatastorage.cpp
     webapplication.cpp
     webui.cpp
 )

src/webui/api/clientdatacontroller.cpp

@@ -0,0 +1,88 @@
+/*
+ * Bittorrent Client using Qt and libtorrent.
+ * Copyright (C) 2025  Thomas Piccirello <[email protected]>
+ *
+ * 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.
+ */
+
+#include "clientdatacontroller.h"
+
+#include <QJsonArray>
+#include <QJsonDocument>
+#include <QJsonObject>
+
+#include "base/global.h"
+#include "base/interfaces/iapplication.h"
+#include "base/logger.h"
+#include "apierror.h"
+#include "webui/clientdatastorage.h"
+
+ClientDataController::ClientDataController(ClientDataStorage *clientDataStorage, IApplication *app, QObject *parent)
+    : APIController(app, parent)
+    , m_clientDataStorage {clientDataStorage}
+{
+}
+
+void ClientDataController::loadAction()
+{
+    const QString keysParam {params()[u"keys"_s]};
+    if (keysParam.isEmpty())
+    {
+        setResult(m_clientDataStorage->loadData());
+        return;
+    }
+
+    QJsonParseError jsonError;
+    const auto keysJsonDocument = QJsonDocument::fromJson(keysParam.toUtf8(), &jsonError);
+    if (jsonError.error != QJsonParseError::NoError)
+        throw APIError(APIErrorType::BadParams, jsonError.errorString());
+    if (!keysJsonDocument.isArray())
+        throw APIError(APIErrorType::BadParams, tr("`keys` must be an array"));
+
+    QStringList keys;
+    for (const QJsonValue &keysJsonVal : asConst(keysJsonDocument.array()))
+    {
+        if (!keysJsonVal.isString())
+            throw APIError(APIErrorType::BadParams, tr("Items of `keys` must be strings"));
+
+        keys << keysJsonVal.toString();
+    }
+
+    setResult(m_clientDataStorage->loadData(keys));
+}
+
+void ClientDataController::storeAction()
+{
+    requireParams({u"data"_s});
+    QJsonParseError jsonError;
+    const auto dataJsonDocument = QJsonDocument::fromJson(params()[u"data"_s].toUtf8(), &jsonError);
+    if (jsonError.error != QJsonParseError::NoError)
+        throw APIError(APIErrorType::BadParams, jsonError.errorString());
+    if (!dataJsonDocument.isObject())
+        throw APIError(APIErrorType::BadParams, tr("`data` must be an object"));
+
+    const nonstd::expected<void, QString> result = m_clientDataStorage->storeData(dataJsonDocument.object());
+    if (!result)
+        throw APIError(APIErrorType::Conflict, result.error());
+}

src/webui/api/clientdatacontroller.h

@@ -0,0 +1,49 @@
+/*
+ * Bittorrent Client using Qt and libtorrent.
+ * Copyright (C) 2025  Thomas Piccirello <[email protected]>
+ *
+ * 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
+
+#include "apicontroller.h"
+
+class ClientDataStorage;
+
+class ClientDataController final : public APIController
+{
+    Q_OBJECT
+    Q_DISABLE_COPY_MOVE(ClientDataController)
+
+public:
+    ClientDataController(ClientDataStorage *clientDataStorage, IApplication *app, QObject *parent = nullptr);
+
+private slots:
+    void loadAction();
+    void storeAction();
+
+private:
+    ClientDataStorage *m_clientDataStorage = nullptr;
+};

src/webui/clientdatastorage.cpp

@@ -0,0 +1,138 @@
+/*
+ * Bittorrent Client using Qt and libtorrent.
+ * Copyright (C) 2025  Thomas Piccirello <[email protected]>
+ *
+ * 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.
+ */
+
+#include "clientdatastorage.h"
+
+#include <QJsonDocument>
+#include <QJsonObject>
+
+#include "base/global.h"
+#include "base/logger.h"
+#include "base/path.h"
+#include "base/profile.h"
+#include "base/utils/io.h"
+
+const int CLIENT_DATA_FILE_MAX_SIZE = 1024 * 1024; // 1 MiB
+const QString CLIENT_DATA_FILE_NAME = u"web_clientdata.json"_s;
+
+ClientDataStorage::ClientDataStorage(QObject *parent)
+    : QObject(parent)
+    , m_clientDataFilePath(specialFolderLocation(SpecialFolder::Data) / Path(CLIENT_DATA_FILE_NAME))
+{
+    if (!m_clientDataFilePath.exists())
+        return;
+
+    const auto readResult = Utils::IO::readFile(m_clientDataFilePath, CLIENT_DATA_FILE_MAX_SIZE);
+    if (!readResult)
+    {
+        LogMsg(tr("Failed to load web client data. %1").arg(readResult.error().message), Log::WARNING);
+        return;
+    }
+
+    QJsonParseError jsonError;
+    const QJsonDocument jsonDoc = QJsonDocument::fromJson(readResult.value(), &jsonError);
+    if (jsonError.error != QJsonParseError::NoError)
+    {
+        LogMsg(tr("Failed to parse web client data. File: \"%1\". Error: \"%2\"")
+            .arg(m_clientDataFilePath.toString(), jsonError.errorString()), Log::WARNING);
+        return;
+    }
+
+    if (!jsonDoc.isObject())
+    {
+        LogMsg(tr("Failed to load web client data. File: \"%1\". Error: \"Invalid data format\"")
+            .arg(m_clientDataFilePath.toString()), Log::WARNING);
+        return;
+    }
+
+    m_clientData = jsonDoc.object();
+}
+
+nonstd::expected<void, QString> ClientDataStorage::storeData(const QJsonObject &object)
+{
+    QJsonObject clientData = m_clientData;
+    bool dataModified = false;
+    for (auto it = object.constBegin(), end = object.constEnd(); it != end; ++it)
+    {
+        const QString &key = it.key();
+        const QJsonValue &value = it.value();
+
+        if (value.isNull())
+        {
+            if (auto it = clientData.find(key); it != clientData.end())
+            {
+                clientData.erase(it);
+                dataModified = true;
+            }
+        }
+        else
+        {
+            const auto &existingValue = clientData.find(key);
+            if (existingValue == clientData.end())
+            {
+                clientData.insert(key, value);
+                dataModified = true;
+            }
+            else if (existingValue.value() != value)
+            {
+                existingValue.value() = value;
+                dataModified = true;
+            }
+        }
+    }
+
+    if (dataModified)
+    {
+        const QByteArray json = QJsonDocument(clientData).toJson(QJsonDocument::Compact);
+        if (json.size() > CLIENT_DATA_FILE_MAX_SIZE)
+            return nonstd::make_unexpected(tr("Total web client data must not be larger than %1 bytes").arg(CLIENT_DATA_FILE_MAX_SIZE));
+        const nonstd::expected<void, QString> result = Utils::IO::saveToFile(m_clientDataFilePath, json);
+        if (!result)
+            return nonstd::make_unexpected(tr("Failed to save web client data. Error: \"%1\"").arg(result.error()));
+
+        m_clientData = clientData;
+    }
+
+    return {};
+}
+
+QJsonObject ClientDataStorage::loadData() const
+{
+    return m_clientData;
+}
+
+QJsonObject ClientDataStorage::loadData(const QStringList &keys) const
+{
+    QJsonObject clientData;
+    for (const QString &key : keys)
+    {
+        if (const auto iter = m_clientData.constFind(key); iter != m_clientData.constEnd())
+            clientData.insert(key, iter.value());
+    }
+    return clientData;
+}

src/webui/clientdatastorage.h

@@ -0,0 +1,51 @@
+/*
+ * Bittorrent Client using Qt and libtorrent.
+ * Copyright (C) 2025  Thomas Piccirello <[email protected]>
+ *
+ * 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
+
+#include <QJsonObject>
+
+#include "base/3rdparty/expected.hpp"
+#include "base/path.h"
+
+class ClientDataStorage final : public QObject
+{
+    Q_OBJECT
+    Q_DISABLE_COPY_MOVE(ClientDataStorage)
+
+public:
+    ClientDataStorage(QObject *parent = nullptr);
+
+    nonstd::expected<void, QString> storeData(const QJsonObject &object);
+    QJsonObject loadData() const;
+    QJsonObject loadData(const QStringList &keys) const;
+
+private:
+    Path m_clientDataFilePath;
+    QJsonObject m_clientData;
+};