feat: use qt json support components in data object and infos gathering module

29 files changed, 792 insertions, 631 deletions

diff --git a/src/core/function/CacheManager.cpp b/src/core/function/CacheManager.cpp
index 88d3bddd..90396017 100644
--- a/src/core/function/CacheManager.cpp
+++ b/src/core/function/CacheManager.cpp
@@ -98,25 +98,23 @@ class CacheManager::Impl : public QObject {
             &Impl::slot_flush_cache_storage);
     flush_timer_->start(15000);
 
+    // load data from storage
     load_all_cache_storage();
   }
 
-  void SaveCache(QString key, const nlohmann::json& value, bool flush) {
+  void SaveCache(QString key, const QJsonDocument& value, bool flush) {
     auto data_object_key = get_data_object_key(key);
     cache_storage_.insert(key, value);
 
-    if (std::find(key_storage_.begin(), key_storage_.end(),
-                  key.toStdString()) == key_storage_.end()) {
+    if (!key_storage_.contains(key)) {
       GF_CORE_LOG_DEBUG("register new key of cache", key);
-      key_storage_.push_back(key.toStdString());
+      key_storage_.push_back(key);
     }
 
-    if (flush) {
-      slot_flush_cache_storage();
-    }
+    if (flush) slot_flush_cache_storage();
   }
 
-  auto LoadCache(const QString& key) -> nlohmann::json {
+  auto LoadCache(const QString& key) -> QJsonDocument {
     auto data_object_key = get_data_object_key(key);
 
     if (!cache_storage_.exists(key)) {
@@ -124,14 +122,12 @@ class CacheManager::Impl : public QObject {
     }
 
     auto cache = cache_storage_.get(key);
-    if (cache) {
-      return *cache;
-    }
+    if (cache.has_value()) return cache.value();
     return {};
   }
 
-  auto LoadCache(const QString& key, nlohmann::json default_value)
-      -> nlohmann::json {
+  auto LoadCache(const QString& key, QJsonDocument default_value)
+      -> QJsonDocument {
     auto data_object_key = get_data_object_key(key);
     if (!cache_storage_.exists(key)) {
       cache_storage_.insert(key,
@@ -139,9 +135,7 @@ class CacheManager::Impl : public QObject {
     }
 
     auto cache = cache_storage_.get(key);
-    if (cache) {
-      return *cache;
-    }
+    if (cache.has_value()) return cache.value();
     return {};
   }
 
@@ -159,18 +153,17 @@ class CacheManager::Impl : public QObject {
   void slot_flush_cache_storage() {
     for (const auto& cache : cache_storage_.mirror()) {
       auto key = get_data_object_key(cache.first);
-      GF_CORE_LOG_TRACE("save cache into filesystem, key {}, value size: {}",
-                        key, cache.second.size());
-      GpgFrontend::DataObjectOperator::GetInstance().SaveDataObj(key,
-                                                                 cache.second);
+      GF_CORE_LOG_TRACE("save cache into filesystem, key {}", key);
+      GpgFrontend::DataObjectOperator::GetInstance().SaveDataObj(
+          key, QJsonDocument(cache.second));
     }
-    GpgFrontend::DataObjectOperator::GetInstance().SaveDataObj(drk_key_,
-                                                               key_storage_);
+    GpgFrontend::DataObjectOperator::GetInstance().SaveDataObj(
+        drk_key_, QJsonDocument(key_storage_));
   }
 
  private:
-  ThreadSafeMap<QString, nlohmann::json> cache_storage_;
-  nlohmann::json key_storage_;
+  ThreadSafeMap<QString, QJsonDocument> cache_storage_;
+  QJsonArray key_storage_;
   QTimer* flush_timer_;
   const QString drk_key_ = "__cache_manage_data_register_key_list";
 
@@ -189,18 +182,16 @@ class CacheManager::Impl : public QObject {
    *
    * @param key
    * @param default_value
-   * @return nlohmann::json
+   * @return QJsonObject
    */
-  static auto load_cache_storage(QString key, nlohmann::json default_value)
-      -> nlohmann::json {
+  static auto load_cache_storage(QString key, QJsonDocument default_value)
+      -> QJsonDocument {
     auto data_object_key = get_data_object_key(std::move(key));
     auto stored_data =
         GpgFrontend::DataObjectOperator::GetInstance().GetDataObject(
             data_object_key);
 
-    if (stored_data.has_value()) {
-      return stored_data.value();
-    }
+    if (stored_data.has_value()) return stored_data.value();
     return default_value;
   }
 
@@ -214,20 +205,16 @@ class CacheManager::Impl : public QObject {
         GpgFrontend::DataObjectOperator::GetInstance().GetDataObject(drk_key_);
 
     // get cache data list from file system
-    nlohmann::json registered_key_list;
-    if (stored_data.has_value()) {
-      registered_key_list = std::move(stored_data.value());
-    }
-
-    if (!registered_key_list.is_array()) {
+    QJsonArray registered_key_list;
+    if (stored_data->isArray()) {
+      registered_key_list = stored_data->array();
+    } else {
       GpgFrontend::DataObjectOperator::GetInstance().SaveDataObj(
-          drk_key_, nlohmann::json::array());
-      GF_CORE_LOG_ERROR("drk_key_ is not an array, abort.");
-      return;
+          drk_key_, QJsonDocument(QJsonArray()));
     }
 
     for (const auto& key : registered_key_list) {
-      load_cache_storage(QString::fromStdString(key), {});
+      load_cache_storage(key.toString(), {});
     }
 
     key_storage_ = registered_key_list;
@@ -247,17 +234,17 @@ CacheManager::CacheManager(int channel)
 
 CacheManager::~CacheManager() = default;
 
-void CacheManager::SaveCache(QString key, const nlohmann::json& value,
+void CacheManager::SaveCache(QString key, const QJsonDocument& value,
                              bool flush) {
   p_->SaveCache(std::move(key), value, flush);
 }
 
-auto CacheManager::LoadCache(QString key) -> nlohmann::json {
+auto CacheManager::LoadCache(QString key) -> QJsonDocument {
   return p_->LoadCache(key);
 }
 
-auto CacheManager::LoadCache(QString key, nlohmann::json default_value)
-    -> nlohmann::json {
+auto CacheManager::LoadCache(QString key, QJsonDocument default_value)
+    -> QJsonDocument {
   return p_->LoadCache(key, std::move(default_value));
 }
 
diff --git a/src/core/function/CacheManager.h b/src/core/function/CacheManager.h
index 9e95096d..96496648 100644
--- a/src/core/function/CacheManager.h
+++ b/src/core/function/CacheManager.h
@@ -28,8 +28,6 @@
 
 #pragma once
 
-#include <nlohmann/json.hpp>
-
 #include "core/function/basic/GpgFunctionObject.h"
 
 namespace GpgFrontend {
@@ -42,11 +40,11 @@ class GPGFRONTEND_CORE_EXPORT CacheManager
 
   ~CacheManager() override;
 
-  void SaveCache(QString key, const nlohmann::json& value, bool flush = false);
+  void SaveCache(QString key, const QJsonDocument& value, bool flush = false);
 
-  auto LoadCache(QString key) -> nlohmann::json;
+  auto LoadCache(QString key) -> QJsonDocument;
 
-  auto LoadCache(QString key, nlohmann::json default_value) -> nlohmann::json;
+  auto LoadCache(QString key, QJsonDocument default_value) -> QJsonDocument;
 
   auto ResetCache(QString key) -> bool;
 
diff --git a/src/core/function/DataObjectOperator.cpp b/src/core/function/DataObjectOperator.cpp
index 3033f23b..1d4d2c4a 100644
--- a/src/core/function/DataObjectOperator.cpp
+++ b/src/core/function/DataObjectOperator.cpp
@@ -36,7 +36,7 @@
 namespace GpgFrontend {
 
 void DataObjectOperator::init_app_secure_key() {
-  GF_CORE_LOG_TRACE("initializing application secure key");
+  GF_CORE_LOG_INFO("initializing application secure key...");
   WriteFile(app_secure_key_path_,
             PassphraseGenerator::GetInstance().Generate(256).toUtf8());
   QFile::setPermissions(app_secure_key_path_,
@@ -46,97 +46,95 @@ void DataObjectOperator::init_app_secure_key() {
 DataObjectOperator::DataObjectOperator(int channel)
     : SingletonFunctionObject<DataObjectOperator>(channel) {
   if (!QDir(app_secure_path_).exists()) QDir(app_secure_path_).mkdir(".");
-
-  if (!QDir(app_secure_key_path_).exists()) {
-    init_app_secure_key();
-  }
+  if (!QFileInfo(app_secure_key_path_).exists()) init_app_secure_key();
 
   QByteArray key;
   if (!ReadFile(app_secure_key_path_, key)) {
     GF_CORE_LOG_ERROR("failed to read app secure key file: {}",
                       app_secure_key_path_);
-    throw std::runtime_error("failed to read app secure key file");
+    // unsafe mode
+    key = {};
   }
+
   hash_key_ = QCryptographicHash::hash(key, QCryptographicHash::Sha256);
-  GF_CORE_LOG_TRACE("app secure key loaded {} bytes", hash_key_.size());
 
-  if (!QDir(app_data_objs_path_).exists()) QDir(app_data_objs_path_).mkpath(".");
+  if (!QDir(app_data_objs_path_).exists()) {
+    QDir(app_data_objs_path_).mkpath(".");
+  }
 }
 
-auto DataObjectOperator::SaveDataObj(const QString& _key,
-                                     const nlohmann::json& value) -> QString {
+auto DataObjectOperator::SaveDataObj(const QString& key,
+                                     const QJsonDocument& value) -> QString {
   QByteArray hash_obj_key = {};
-  if (_key.isEmpty()) {
+  if (key.isEmpty()) {
     hash_obj_key =
         QCryptographicHash::hash(
-            hash_key_
-                .append(
-                    PassphraseGenerator::GetInstance().Generate(32).toUtf8())
-                .append(QDateTime::currentDateTime().toString().toUtf8()),
+            hash_key_ +
+                PassphraseGenerator::GetInstance().Generate(32).toUtf8() +
+                QDateTime::currentDateTime().toString().toUtf8(),
             QCryptographicHash::Sha256)
             .toHex();
   } else {
-    hash_obj_key = QCryptographicHash::hash(hash_key_.append(_key.toUtf8()),
+    hash_obj_key = QCryptographicHash::hash(hash_key_ + key.toUtf8(),
                                             QCryptographicHash::Sha256)
                        .toHex();
   }
 
-  const auto obj_path = app_data_objs_path_ + "/" + hash_obj_key;
-
-  QAESEncryption encryption(QAESEncryption::AES_256, QAESEncryption::ECB,
-                            QAESEncryption::Padding::ISO);
-  auto encoded =
-      encryption.encode(QByteArray::fromStdString(to_string(value)), hash_key_);
-  GF_CORE_LOG_TRACE("saving data object {} to {} , size: {} bytes",
-                    hash_obj_key, obj_path, encoded.size());
-
-  WriteFile(obj_path, encoded);
+  const auto target_obj_path = app_data_objs_path_ + "/" + hash_obj_key;
+  auto encoded_data =
+      QAESEncryption(QAESEncryption::AES_256, QAESEncryption::ECB,
+                     QAESEncryption::Padding::ISO)
+          .encode(value.toJson(), hash_key_);
+  GF_CORE_LOG_TRACE("saving data object {} to disk {} , size: {} bytes",
+                    hash_obj_key, target_obj_path, encoded_data.size());
+
+  // recreate if not exists
+  if (!QDir(app_data_objs_path_).exists()) {
+    QDir(app_data_objs_path_).mkpath(".");
+  }
 
-  return _key.isEmpty() ? hash_obj_key : QString();
+  if (!WriteFile(target_obj_path, encoded_data)) {
+    GF_CORE_LOG_ERROR("failed to write data object to disk: {}", key);
+  }
+  return key.isEmpty() ? hash_obj_key : QString();
 }
 
-auto DataObjectOperator::GetDataObject(const QString& _key)
-    -> std::optional<nlohmann::json> {
+auto DataObjectOperator::GetDataObject(const QString& key)
+    -> std::optional<QJsonDocument> {
   try {
-    GF_CORE_LOG_TRACE("get data object from disk {}", _key);
-    auto hash_obj_key =
-        QCryptographicHash::hash(hash_key_.append(_key.toUtf8()),
-                                 QCryptographicHash::Sha256)
-            .toHex();
+    GF_CORE_LOG_TRACE("try to get data object from disk, key: {}", key);
+    auto hash_obj_key = QCryptographicHash::hash(hash_key_ + key.toUtf8(),
+                                                 QCryptographicHash::Sha256)
+                            .toHex();
 
     const auto obj_path = app_data_objs_path_ + "/" + hash_obj_key;
-
     if (!QFileInfo(obj_path).exists()) {
-      GF_CORE_LOG_WARN("data object not found, key: {}", _key);
+      GF_CORE_LOG_WARN("data object not found from disk, key: {}", key);
       return {};
     }
 
     QByteArray encoded_data;
     if (!ReadFile(obj_path, encoded_data)) {
-      GF_CORE_LOG_ERROR("failed to read data object, key: {}", _key);
+      GF_CORE_LOG_ERROR("failed to read data object from disk, key: {}", key);
       return {};
     }
 
     QAESEncryption encryption(QAESEncryption::AES_256, QAESEncryption::ECB,
                               QAESEncryption::Padding::ISO);
 
-    GF_CORE_LOG_TRACE("decrypting data object {} , hash key size: {}",
-                      encoded_data.size(), hash_key_.size());
-
-    auto decoded =
+    auto decoded_data =
         encryption.removePadding(encryption.decode(encoded_data, hash_key_));
-
-    GF_CORE_LOG_TRACE("data object decoded: {}", _key);
-
-    return nlohmann::json::parse(decoded.toStdString());
+    GF_CORE_LOG_TRACE("data object has been decoded, key: {}, data: {}", key,
+                      decoded_data);
+    return QJsonDocument::fromJson(decoded_data);
   } catch (...) {
-    GF_CORE_LOG_ERROR("failed to get data object, caught exception: {}", _key);
+    GF_CORE_LOG_ERROR("failed to get data object, caught exception: {}", key);
     return {};
   }
 }
 
 auto DataObjectOperator::GetDataObjectByRef(const QString& _ref)
-    -> std::optional<nlohmann::json> {
+    -> std::optional<QJsonDocument> {
   if (_ref.size() != 64) return {};
 
   try {
@@ -151,10 +149,10 @@ auto DataObjectOperator::GetDataObjectByRef(const QString& _ref)
     QAESEncryption encryption(QAESEncryption::AES_256, QAESEncryption::ECB,
                               QAESEncryption::Padding::ISO);
 
-    auto decoded =
+    auto decoded_data =
         encryption.removePadding(encryption.decode(encoded_data, hash_key_));
 
-    return nlohmann::json::parse(decoded.toStdString());
+    return QJsonDocument::fromJson(decoded_data);
   } catch (...) {
     return {};
   }
diff --git a/src/core/function/DataObjectOperator.h b/src/core/function/DataObjectOperator.h
index 3d0606d6..992b0c46 100644
--- a/src/core/function/DataObjectOperator.h
+++ b/src/core/function/DataObjectOperator.h
@@ -28,7 +28,6 @@
 
 #pragma once
 
-#include <nlohmann/json.hpp>
 #include <optional>
 
 #include "core/function/GlobalSettingStation.h"
@@ -47,11 +46,11 @@ class GPGFRONTEND_CORE_EXPORT DataObjectOperator
   explicit DataObjectOperator(
       int channel = SingletonFunctionObject::GetDefaultChannel());
 
-  auto SaveDataObj(const QString &_key, const nlohmann::json &value) -> QString;
+  auto SaveDataObj(const QString &_key, const QJsonDocument &value) -> QString;
 
-  auto GetDataObject(const QString &_key) -> std::optional<nlohmann::json>;
+  auto GetDataObject(const QString &_key) -> std::optional<QJsonDocument>;
 
-  auto GetDataObjectByRef(const QString &_ref) -> std::optional<nlohmann::json>;
+  auto GetDataObjectByRef(const QString &_ref) -> std::optional<QJsonDocument>;
 
  private:
   /**
@@ -69,9 +68,7 @@ class GPGFRONTEND_CORE_EXPORT DataObjectOperator
       app_secure_path_ +
       "/app.key";  ///< Where the key of data object is stored
   QString app_data_objs_path_ =
-      global_setting_station_.GetAppDataPath() + "/data_objs";  ///< Where data
-                                                                ///< object is
-                                                                ///< stored
+      global_setting_station_.GetAppDataPath() + "/data_objs";
 
   QByteArray hash_key_;  ///< Hash key
 };
diff --git a/src/core/utils/CacheUtils.cpp b/src/core/utils/CacheUtils.cpp
index 575634ae..5e8657fa 100644
--- a/src/core/utils/CacheUtils.cpp
+++ b/src/core/utils/CacheUtils.cpp
@@ -33,14 +33,17 @@
 namespace GpgFrontend {
 
 void SetTempCacheValue(const QString& key, const QString& value) {
-  nlohmann::json cache_json = value.toStdString();
-  CacheManager::GetInstance().SaveCache(key, cache_json);
+  QJsonDocument json;
+  json.setObject(QJsonObject({{key, value}}));
+  CacheManager::GetInstance().SaveCache(key, json);
 }
 
 auto GetTempCacheValue(const QString& key) -> QString {
-  nlohmann::json cache_json = "";
-  cache_json = CacheManager::GetInstance().LoadCache(key, cache_json);
-  return QString::fromStdString(cache_json.template get<std::string>());
+  QJsonDocument json = CacheManager::GetInstance().LoadCache(key);
+  if (!json.isObject()) return {};
+  auto json_object = json.object();
+  if (!json_object.contains(key) && json_object[key].isString()) return {};
+  return json_object[key].toString();
 }
 
 void ResetTempCacheValue(const QString& key) {
diff --git a/src/module/integrated/gnupg_info_gathering_module/GnuPGInfoGatheringModule.cpp b/src/module/integrated/gnupg_info_gathering_module/GnuPGInfoGatheringModule.cpp
index c7b87b5b..0db639f8 100644
--- a/src/module/integrated/gnupg_info_gathering_module/GnuPGInfoGatheringModule.cpp
+++ b/src/module/integrated/gnupg_info_gathering_module/GnuPGInfoGatheringModule.cpp
@@ -28,8 +28,6 @@
 
 #include "GnuPGInfoGatheringModule.h"
 
-#include <nlohmann/json.hpp>
-#include <string>
 #include <vector>
 
 #include "GpgInfo.h"
@@ -43,8 +41,8 @@ auto CheckBinaryChacksum(QString path) -> std::optional<QString> {
   // check file info and access rights
   QFileInfo info(path);
   if (!info.exists() || !info.isFile() || !info.isReadable()) {
-    MODULE_LOG_ERROR("get info for file {} error, exists: {}",
-                     info.filePath().toStdString(), info.exists());
+    MODULE_LOG_ERROR("get info for file {} error, exists: {}", info.filePath(),
+                     info.exists());
     return {};
   }
 
@@ -52,7 +50,7 @@ auto CheckBinaryChacksum(QString path) -> std::optional<QString> {
   QFile f(info.filePath());
   if (!f.open(QIODevice::ReadOnly)) {
     MODULE_LOG_ERROR("open {} to calculate check sum error: {}", path,
-                     f.errorString().toStdString());
+                     f.errorString());
     return {};
   }
 
@@ -122,7 +120,7 @@ auto GnuPGInfoGatheringModule::Exec(EventRefrernce event) -> int {
          GpgComponentInfo c_i_gpgme;
          c_i_gpgme.name = "gpgme";
          c_i_gpgme.desc = "GPG Made Easy";
-         c_i_gpgme.version = gpgme_version.toStdString();
+         c_i_gpgme.version = gpgme_version;
          c_i_gpgme.path = _("Embedded In");
          c_i_gpgme.binary_checksum = "/";
 
@@ -130,24 +128,22 @@ auto GnuPGInfoGatheringModule::Exec(EventRefrernce event) -> int {
          c_i_gpgconf.name = "gpgconf";
          c_i_gpgconf.desc = "GPG Configure";
          c_i_gpgconf.version = "/";
-         c_i_gpgconf.path = gpgconf_path.toStdString();
+         c_i_gpgconf.path = gpgconf_path;
          auto gpgconf_binary_checksum = CheckBinaryChacksum(gpgconf_path);
          c_i_gpgconf.binary_checksum = (gpgconf_binary_checksum.has_value()
                                             ? gpgconf_binary_checksum.value()
-                                            : QString("/"))
-                                           .toStdString();
+                                            : QString("/"));
 
          component_infos.push_back(c_i_gpgme);
          component_infos.push_back(c_i_gpgconf);
 
-         nlohmann::json const jsonlized_gpgme_component_info = c_i_gpgme;
-         nlohmann::json const jsonlized_gpgconf_component_info = c_i_gpgconf;
+         auto const jsonlized_gpgme_component_info = c_i_gpgme.Json();
+         auto const jsonlized_gpgconf_component_info = c_i_gpgconf.Json();
          UpsertRTValue(GetModuleIdentifier(), "gnupg.components.gpgme",
-                       QString::fromStdString(static_cast<std::string>(
-                           jsonlized_gpgme_component_info.dump())));
-         UpsertRTValue(GetModuleIdentifier(), "gnupg.components.gpgconf",
-                       QString::fromStdString(static_cast<std::string>(
-                           jsonlized_gpgme_component_info.dump())));
+                       QJsonDocument(jsonlized_gpgme_component_info).toJson());
+         UpsertRTValue(
+             GetModuleIdentifier(), "gnupg.components.gpgconf",
+             QJsonDocument(jsonlized_gpgconf_component_info).toJson());
 
          auto line_split_list = p_out.split("\n");
 
@@ -194,20 +190,18 @@ auto GnuPGInfoGatheringModule::Exec(EventRefrernce event) -> int {
 
            {
              GpgComponentInfo c_i;
-             c_i.name = component_name.toStdString();
-             c_i.desc = component_desc.toStdString();
-             c_i.version = version.toStdString();
-             c_i.path = component_path.toStdString();
+             c_i.name = component_name;
+             c_i.desc = component_desc;
+             c_i.version = version;
+             c_i.path = component_path;
              c_i.binary_checksum =
                  (binary_checksum.has_value() ? binary_checksum.value()
-                                              : QString("/"))
-                     .toStdString();
+                                              : QString("/"));
 
-             nlohmann::json const jsonlized_component_info = c_i;
+             auto const jsonlized_component_info = c_i.Json();
              UpsertRTValue(GetModuleIdentifier(),
                            QString("gnupg.components.%1").arg(component_name),
-                           QString::fromStdString(static_cast<std::string>(
-                               jsonlized_component_info.dump())));
+                           QJsonDocument(jsonlized_component_info).toJson());
 
              component_infos.push_back(c_i);
            }
@@ -270,11 +264,13 @@ auto GnuPGInfoGatheringModule::Exec(EventRefrernce event) -> int {
   for (const auto &component : components) {
     auto component_info_json = RetrieveRTValueTypedOrDefault(
         "com.bktus.gpgfrontend.module.integrated.gnupg-info-gathering",
-        QString("gnupg.components.%1").arg(component), QString{});
+        QString("gnupg.components.%1").arg(component), QByteArray{});
 
     auto jsonlized_component_info =
-        nlohmann::json::parse(component_info_json.toStdString());
-    auto component_info = jsonlized_component_info.get<GpgComponentInfo>();
+        QJsonDocument::fromJson(component_info_json);
+    assert(jsonlized_component_info.isObject());
+
+    auto component_info = GpgComponentInfo(jsonlized_component_info.object());
     MODULE_LOG_DEBUG("gpgconf check options ready, component: {}",
                      component_info.name);
 
@@ -284,7 +280,7 @@ auto GnuPGInfoGatheringModule::Exec(EventRefrernce event) -> int {
 
     exec_contexts.emplace_back(GpgCommandExecutor::ExecuteContext{
         gpgconf_path,
-        {"--list-options", component_info.name.c_str()},
+        {"--list-options", component_info.name},
         [this, component_info](int exit_code, const QString &p_out,
                                const QString &p_err) {
           MODULE_LOG_DEBUG(
@@ -328,24 +324,23 @@ auto GnuPGInfoGatheringModule::Exec(EventRefrernce event) -> int {
             auto option_value = info_split_list[9].trimmed();
 
             GpgOptionsInfo info;
-            info.name = option_name.toStdString();
-            info.flags = option_flags.toStdString();
-            info.level = option_level.toStdString();
-            info.description = option_desc.toStdString();
-            info.type = option_type.toStdString();
-            info.alt_type = option_alt_type.toStdString();
-            info.argname = option_argname.toStdString();
-            info.default_value = option_default.toStdString();
-            info.argdef = option_argdef.toStdString();
-            info.value = option_value.toStdString();
-
-            nlohmann::json const jsonlized_option_info = info;
+            info.name = option_name;
+            info.flags = option_flags;
+            info.level = option_level;
+            info.description = option_desc;
+            info.type = option_type;
+            info.alt_type = option_alt_type;
+            info.argname = option_argname;
+            info.default_value = option_default;
+            info.argdef = option_argdef;
+            info.value = option_value;
+
+            auto const jsonlized_option_info = info.Json();
             UpsertRTValue(GetModuleIdentifier(),
                           QString("gnupg.components.%1.options.%2")
-                              .arg(component_info.name.c_str())
+                              .arg(component_info.name)
                               .arg(option_name),
-                          QString::fromStdString(static_cast<std::string>(
-                              jsonlized_option_info.dump())));
+                          QJsonDocument(jsonlized_option_info).toJson());
             options_infos.push_back(info);
           }
         },
diff --git a/src/module/integrated/gnupg_info_gathering_module/GpgInfo.cpp b/src/module/integrated/gnupg_info_gathering_module/GpgInfo.cpp
index 8d6fef74..2015bc0a 100644
--- a/src/module/integrated/gnupg_info_gathering_module/GpgInfo.cpp
+++ b/src/module/integrated/gnupg_info_gathering_module/GpgInfo.cpp
@@ -28,4 +28,53 @@
 
 #include "module/integrated/gnupg_info_gathering_module/GpgInfo.h"
 
-namespace GpgFrontend::Module::Integrated::GnuPGInfoGatheringModule {}
+namespace GpgFrontend::Module::Integrated::GnuPGInfoGatheringModule {
+
+GpgOptionsInfo::GpgOptionsInfo(const QJsonObject &j) {
+  if (const auto v = j["name"]; v.isString()) name = v.toString();
+  if (const auto v = j["flags"]; v.isString()) flags = v.toString();
+  if (const auto v = j["level"]; v.isString()) level = v.toString();
+  if (const auto v = j["description"]; v.isString()) description = v.toString();
+  if (const auto v = j["type"]; v.isString()) type = v.toString();
+  if (const auto v = j["alt_type"]; v.isString()) alt_type = v.toString();
+  if (const auto v = j["argname"]; v.isString()) argname = v.toString();
+  if (const auto v = j["default_value"]; v.isString())
+    default_value = v.toString();
+  if (const auto v = j["argdef"]; v.isString()) argdef = v.toString();
+  if (const auto v = j["value"]; v.isString()) value = v.toString();
+}
+
+auto GpgOptionsInfo::Json() const -> QJsonObject {
+  QJsonObject j;
+  j["name"] = name;
+  j["flags"] = flags;
+  j["level"] = level;
+  j["description"] = description;
+  j["type"] = type;
+  j["alt_type"] = alt_type;
+  j["argname"] = argname;
+  j["default_value"] = default_value;
+  j["argdef"] = argdef;
+  j["value"] = value;
+  return j;
+}
+
+auto GpgComponentInfo::Json() const -> QJsonObject {
+  QJsonObject j;
+  j["name"] = name;
+  j["desc"] = desc;
+  j["version"] = version;
+  j["path"] = path;
+  j["binary_checksum"] = binary_checksum;
+  return j;
+}
+
+GpgComponentInfo::GpgComponentInfo(const QJsonObject &j) {
+  if (const auto v = j["name"]; v.isString()) name = v.toString();
+  if (const auto v = j["desc"]; v.isString()) desc = v.toString();
+  if (const auto v = j["version"]; v.isString()) version = v.toString();
+  if (const auto v = j["path"]; v.isString()) path = v.toString();
+  if (const auto v = j["binary_checksum"]; v.isString())
+    binary_checksum = v.toString();
+}
+}  // namespace GpgFrontend::Module::Integrated::GnuPGInfoGatheringModule
diff --git a/src/module/integrated/gnupg_info_gathering_module/GpgInfo.h b/src/module/integrated/gnupg_info_gathering_module/GpgInfo.h
index 943832c3..72513bc8 100644
--- a/src/module/integrated/gnupg_info_gathering_module/GpgInfo.h
+++ b/src/module/integrated/gnupg_info_gathering_module/GpgInfo.h
@@ -50,35 +50,40 @@ class GpgInfo {
  *
  */
 struct GpgComponentInfo {
-  std::string name;
-  std::string desc;
-  std::string version;
-  std::string path;
-  std::string binary_checksum;
-};
+  QString name;
+  QString desc;
+  QString version;
+  QString path;
+  QString binary_checksum;
+
+  GpgComponentInfo() = default;
 
-NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE(GpgComponentInfo, name, desc, version, path,
-                                   binary_checksum);
+  explicit GpgComponentInfo(const QJsonObject &j);
+
+  [[nodiscard]] auto Json() const -> QJsonObject;
+};
 
 /**
  * The format of each line is:
  * name:flags:level:description:type:alt-type:argname:default:argdef:value
  */
 struct GpgOptionsInfo {
-  std::string name;
-  std::string flags;
-  std::string level;
-  std::string description;
-  std::string type;
-  std::string alt_type;
-  std::string argname;
-  std::string default_value;
-  std::string argdef;
-  std::string value;
-};
+  QString name;
+  QString flags;
+  QString level;
+  QString description;
+  QString type;
+  QString alt_type;
+  QString argname;
+  QString default_value;
+  QString argdef;
+  QString value;
+
+  GpgOptionsInfo() = default;
 
-NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE(GpgOptionsInfo, name, flags, level,
-                                   description, type, alt_type, argname,
-                                   default_value, argdef, value);
+  explicit GpgOptionsInfo(const QJsonObject &j);
+
+  [[nodiscard]] auto Json() const -> QJsonObject;
+};
 
 }  // namespace GpgFrontend::Module::Integrated::GnuPGInfoGatheringModule
diff --git a/src/ui/UserInterfaceUtils.cpp b/src/ui/UserInterfaceUtils.cpp
index 2c353d19..69534ca6 100644
--- a/src/ui/UserInterfaceUtils.cpp
+++ b/src/ui/UserInterfaceUtils.cpp
@@ -32,8 +32,6 @@
 #include <qdialog.h>
 
 #include <QtNetwork>
-#include <string>
-#include <utility>
 #include <vector>
 
 #include "core/GpgConstants.h"
@@ -43,7 +41,6 @@
 #include "core/model/GpgImportInformation.h"
 #include "core/module/ModuleManager.h"
 #include "core/thread/Task.h"
-#include "core/thread/TaskRunner.h"
 #include "core/thread/TaskRunnerGetter.h"
 #include "core/typedef/GpgTypedef.h"
 #include "core/utils/CacheUtils.h"
@@ -52,7 +49,9 @@
 #include "ui/UISignalStation.h"
 #include "ui/dialog/WaitingDialog.h"
 #include "ui/dialog/gnupg/GnuPGControllerDialog.h"
+#include "ui/struct/CacheObject.h"
 #include "ui/struct/SettingsObject.h"
+#include "ui/struct/settings/KeyServerSO.h"
 #include "ui/widgets/TextEdit.h"
 
 namespace GpgFrontend::UI {
@@ -400,36 +399,16 @@ void CommonUtils::SlotExecuteGpgCommand(
 
 void CommonUtils::SlotImportKeyFromKeyServer(
     const KeyIdArgsList &key_ids, const ImportCallbackFunctiopn &callback) {
-  // target key server that we need to import key from it
-  QString target_keyserver;
-
-  try {
-    SettingsObject key_server_json("key_server");
-
-    // get key servers from settings
-    const auto key_server_list =
-        key_server_json.Check("server_list", nlohmann::json::array());
-    if (key_server_list.empty()) {
-      throw std::runtime_error("No key server configured");
-    }
-
-    const size_t target_key_server_index =
-        key_server_json.Check("default_server", 0);
-    if (target_key_server_index >= key_server_list.size()) {
-      throw std::runtime_error("default_server index out of range");
-    }
-    target_keyserver =
-        key_server_list[target_key_server_index].get<std::string>().c_str();
-
-    GF_UI_LOG_DEBUG("set target key server to default Key Server: {}",
-                    target_keyserver);
-  } catch (...) {
-    GF_UI_LOG_ERROR(_("Cannot read default_keyserver From Settings"));
+  auto target_keyserver =
+      KeyServerSO(SettingsObject("key_server")).GetTargetServer();
+  if (target_keyserver.isEmpty()) {
     QMessageBox::critical(nullptr, _("Default Keyserver Not Found"),
                           _("Cannot read default keyserver from your settings, "
                             "please set a default keyserver first"));
     return;
   }
+  GF_UI_LOG_DEBUG("set target key server to default Key Server: {}",
+                  target_keyserver);
 
   auto *thread = QThread::create([target_keyserver, key_ids, callback]() {
     QUrl target_keyserver_url(target_keyserver);
@@ -541,40 +520,37 @@ bool CommonUtils::isApplicationNeedRestart() {
 
 bool CommonUtils::KeyExistsinFavouriteList(const GpgKey &key) {
   // load cache
-  auto key_array = CacheManager::GetInstance().LoadCache("favourite_key_pair");
-  if (!key_array.is_array()) {
-    CacheManager::GetInstance().SaveCache("favourite_key_pair",
-                                          nlohmann::json::array());
-  }
-  return std::find(key_array.begin(), key_array.end(),
-                   key.GetFingerprint().toStdString()) != key_array.end();
+  auto json_data = CacheObject("favourite_key_pair");
+  if (!json_data.isArray()) json_data.setArray(QJsonArray());
+
+  auto key_array = json_data.array();
+  return std::find(key_array.begin(), key_array.end(), key.GetFingerprint()) !=
+         key_array.end();
 }
 
 void CommonUtils::AddKey2Favourtie(const GpgKey &key) {
-  auto key_array = CacheManager::GetInstance().LoadCache("favourite_key_pair");
-  if (!key_array.is_array()) {
-    CacheManager::GetInstance().SaveCache("favourite_key_pair",
-                                          nlohmann::json::array());
-  }
-  key_array.push_back(key.GetFingerprint().toStdString());
-  CacheManager::GetInstance().SaveCache("favourite_key_pair", key_array, true);
+  auto json_data = CacheObject("favourite_key_pair");
+  QJsonArray key_array;
+  if (json_data.isArray()) key_array = json_data.array();
+
+  key_array.push_back(key.GetFingerprint());
+  json_data.setArray(key_array);
 }
 
 void CommonUtils::RemoveKeyFromFavourite(const GpgKey &key) {
-  auto key_array = CacheManager::GetInstance().LoadCache("favourite_key_pair");
-  if (!key_array.is_array()) {
-    CacheManager::GetInstance().SaveCache("favourite_key_pair",
-                                          nlohmann::json::array(), true);
-    return;
-  }
-  auto it = std::find(key_array.begin(), key_array.end(),
-                      key.GetFingerprint().toStdString());
-  if (it != key_array.end()) {
-    auto rm_it = std::remove(key_array.begin(), key_array.end(),
-                             key.GetFingerprint().toStdString());
-    key_array.erase(rm_it, key_array.end());
-    CacheManager::GetInstance().SaveCache("favourite_key_pair", key_array);
+  auto json_data = CacheObject("favourite_key_pair");
+  QJsonArray key_array;
+  if (json_data.isArray()) key_array = json_data.array();
+
+  QString fingerprint = key.GetFingerprint();
+  QJsonArray new_key_array;
+  for (auto &&item : key_array) {
+    if (item.isString() && item.toString() != fingerprint) {
+      new_key_array.append(item);
+    }
   }
+
+  json_data.setArray(new_key_array);
 }
 
 }  // namespace GpgFrontend::UI
\ No newline at end of file
diff --git a/src/ui/dialog/GeneralDialog.cpp b/src/ui/dialog/GeneralDialog.cpp
index 498e2941..386573a3 100644
--- a/src/ui/dialog/GeneralDialog.cpp
+++ b/src/ui/dialog/GeneralDialog.cpp
@@ -29,6 +29,9 @@
 #include "GeneralDialog.h"
 
 #include "ui/struct/SettingsObject.h"
+#include "ui/struct/settings/WindowStateSO.h"
+
+namespace GpgFrontend {
 
 GpgFrontend::UI::GeneralDialog::GeneralDialog(QString name, QWidget *parent)
     : QDialog(parent), name_(std::move(name)) {
@@ -43,12 +46,12 @@ void GpgFrontend::UI::GeneralDialog::slot_restore_settings() noexcept {
     update_rect_cache();
 
     SettingsObject general_windows_state(name_ + "_dialog_state");
-    bool window_save = general_windows_state.Check("window_save", false);
+    auto window_state = WindowStateSO(general_windows_state);
 
     // Restore window size & location
-    if (window_save) {
-      int x = general_windows_state.Check("window_pos").Check("x", 0);
-      int y = general_windows_state.Check("window_pos").Check("y", 0);
+    if (window_state.window_save) {
+      int x = window_state.x;
+      int y = window_state.y;
       GF_UI_LOG_DEBUG("stored dialog pos, x: {}, y: {}", x, y);
 
       QPoint relative_pos = {x, y};
@@ -56,9 +59,8 @@ void GpgFrontend::UI::GeneralDialog::slot_restore_settings() noexcept {
       GF_UI_LOG_DEBUG("relative dialog pos, x: {}, y: {}", relative_pos.x(),
                       relative_pos.y());
 
-      int width = general_windows_state.Check("window_size").Check("width", 0);
-      int height =
-          general_windows_state.Check("window_size").Check("height", 0);
+      int width = window_state.width;
+      int height = window_state.height;
       GF_UI_LOG_DEBUG("stored dialog size, width: {}, height: {}", width,
                       height);
 
@@ -93,12 +95,14 @@ void GpgFrontend::UI::GeneralDialog::slot_save_settings() noexcept {
     GF_UI_LOG_DEBUG("store dialog pos, x: {}, y: {}", relative_pos.x(),
                     relative_pos.y());
 
-    general_windows_state["window_pos"]["x"] = relative_pos.x();
-    general_windows_state["window_pos"]["y"] = relative_pos.y();
+    WindowStateSO window_state;
+    window_state.x = relative_pos.x();
+    window_state.y = relative_pos.y();
+    window_state.width = rect_.width();
+    window_state.height = rect_.height();
+    window_state.window_save = true;
 
-    general_windows_state["window_size"]["width"] = rect_.width();
-    general_windows_state["window_size"]["height"] = rect_.height();
-    general_windows_state["window_save"] = true;
+    general_windows_state.Store(window_state.Json());
 
   } catch (...) {
     GF_UI_LOG_ERROR("general dialog: {}, caught exception", name_);
@@ -210,4 +214,6 @@ void GpgFrontend::UI::GeneralDialog::showEvent(QShowEvent *event) {
   if (!isRectRestored()) movePosition2CenterOfParent();
 
   QDialog::showEvent(event);
-}
\ No newline at end of file
+}
+
+}  // namespace GpgFrontend
\ No newline at end of file
diff --git a/src/ui/dialog/help/GnupgTab.cpp b/src/ui/dialog/help/GnupgTab.cpp
index 9749877f..660732ac 100644
--- a/src/ui/dialog/help/GnupgTab.cpp
+++ b/src/ui/dialog/help/GnupgTab.cpp
@@ -32,8 +32,6 @@
 
 #include "GnupgTab.h"
 
-#include <nlohmann/json.hpp>
-
 #include "core/module/ModuleManager.h"
 #include "ui_GnuPGInfo.h"
 
@@ -99,42 +97,45 @@ void GpgFrontend::UI::GnupgTab::process_software_info() {
 
   int row = 0;
   for (auto& component : components) {
-    auto component_info_json = Module::RetrieveRTValueTypedOrDefault(
+    auto component_info_json_bytes = Module::RetrieveRTValueTypedOrDefault(
         "com.bktus.gpgfrontend.module.integrated.gnupg-info-gathering",
-        QString("gnupg.components.%1").arg(component), QString{});
-    GF_UI_LOG_DEBUG("got gnupg component {} info from rt, info: {}", component,
-                    component_info_json);
+        QString("gnupg.components.%1").arg(component), QByteArray{});
+    GF_UI_LOG_DEBUG("got gnupg component {} info from rt", component);
 
-    auto component_info =
-        nlohmann::json::parse(component_info_json.toStdString());
-    if (!component_info.contains("name")) {
+    auto component_info_json =
+        QJsonDocument::fromJson(component_info_json_bytes);
+    if (!component_info_json.isObject()) {
       GF_UI_LOG_WARN("illegal gnupg component info, json: {}",
-                     component_info_json);
+                     QString(component_info_json_bytes));
+      continue;
+    }
+
+    auto component_info = component_info_json.object();
+    if (!component_info.contains("name")) {
+      GF_UI_LOG_WARN(
+          "illegal gnupg component info. it doesn't have a name, json: {}",
+          QString(component_info_json_bytes));
       continue;
     }
 
-    auto* tmp0 = new QTableWidgetItem(
-        QString::fromStdString(component_info.value("name", "")));
+    auto* tmp0 = new QTableWidgetItem(component_info["name"].toString());
     tmp0->setTextAlignment(Qt::AlignCenter);
     ui_->componentDetailsTable->setItem(row, 0, tmp0);
 
-    auto* tmp1 = new QTableWidgetItem(
-        QString::fromStdString(component_info.value("desc", "")));
+    auto* tmp1 = new QTableWidgetItem(component_info["desc"].toString());
     tmp1->setTextAlignment(Qt::AlignCenter);
     ui_->componentDetailsTable->setItem(row, 1, tmp1);
 
-    auto* tmp2 = new QTableWidgetItem(
-        QString::fromStdString(component_info.value("version", "")));
+    auto* tmp2 = new QTableWidgetItem(component_info["version"].toString());
     tmp2->setTextAlignment(Qt::AlignCenter);
     ui_->componentDetailsTable->setItem(row, 2, tmp2);
 
-    auto* tmp3 = new QTableWidgetItem(
-        QString::fromStdString(component_info.value("binary_checksum", "")));
+    auto* tmp3 =
+        new QTableWidgetItem(component_info["binary_checksum"].toString());
     tmp3->setTextAlignment(Qt::AlignCenter);
     ui_->componentDetailsTable->setItem(row, 3, tmp3);
 
-    auto* tmp4 = new QTableWidgetItem(
-        QString::fromStdString(component_info.value("path", "")));
+    auto* tmp4 = new QTableWidgetItem(component_info["path"].toString());
     tmp4->setTextAlignment(Qt::AlignLeft);
     ui_->componentDetailsTable->setItem(row, 4, tmp4);
 
@@ -150,16 +151,18 @@ void GpgFrontend::UI::GnupgTab::process_software_info() {
         "com.bktus.gpgfrontend.module.integrated.gnupg-info-gathering",
         QString("gnupg.components.%1.options").arg(component));
     for (auto& option : options) {
-      const auto option_info = nlohmann::json::parse(
-          Module::RetrieveRTValueTypedOrDefault(
+      const auto option_info_json =
+          QJsonDocument::fromJson(Module::RetrieveRTValueTypedOrDefault(
               "com.bktus.gpgfrontend.module.integrated.gnupg-info-gathering",
               QString("gnupg.components.%1.options.%2")
                   .arg(component)
                   .arg(option),
-              QString{})
-              .toStdString());
-      if (!option_info.contains("name") ||
-          option_info.value("flags", "1") == "1") {
+              QByteArray{}));
+
+      if (!option_info_json.isObject()) continue;
+
+      auto option_info = option_info_json.object();
+      if (!option_info.contains("name") || option_info["flags"] == "1") {
         continue;
       }
       row++;
@@ -175,26 +178,31 @@ void GpgFrontend::UI::GnupgTab::process_software_info() {
         QString("gnupg.components.%1.options").arg(component));
 
     for (auto& option : options) {
-      auto option_info_json = Module::RetrieveRTValueTypedOrDefault(
+      auto option_info_json_bytes = Module::RetrieveRTValueTypedOrDefault(
           "com.bktus.gpgfrontend.module.integrated.gnupg-info-gathering",
-          QString("gnupg.components.%1.options.%2")
-              .arg(component)
-              .arg(option),
-          QString{});
+          QString("gnupg.components.%1.options.%2").arg(component).arg(option),
+          QByteArray{});
       GF_UI_LOG_DEBUG("got gnupg component's option {} info from rt, info: {}",
-                      component, option_info_json);
+                      component, option_info_json_bytes);
+
+      auto option_info_json = QJsonDocument::fromJson(option_info_json_bytes);
 
-      auto option_info = nlohmann::json::parse(option_info_json.toStdString());
+      if (!option_info_json.isObject()) {
+        GF_UI_LOG_WARN("illegal gnupg option info, json: {}",
+                       QString(option_info_json_bytes));
+        continue;
+      }
 
+      auto option_info = option_info_json.object();
       if (!option_info.contains("name")) {
-        GF_UI_LOG_WARN("illegal gnupg configuation info, json: {}",
-                       option_info_json);
+        GF_UI_LOG_WARN(
+            "illegal gnupg configuation info. it doesn't have a name, json: {}",
+            QString(option_info_json_bytes));
         continue;
       }
 
-      if (option_info.value("flags", "1") == "1") {
-        configuration_group =
-            QString::fromStdString(option_info.value("name", ""));
+      if (option_info["flags"] == "1") {
+        configuration_group = option_info["name"].toString();
         continue;
       }
 
@@ -206,24 +214,21 @@ void GpgFrontend::UI::GnupgTab::process_software_info() {
       tmp1->setTextAlignment(Qt::AlignCenter);
       ui_->configurationDetailsTable->setItem(row, 1, tmp1);
 
-      auto* tmp2 = new QTableWidgetItem(
-          QString::fromStdString(option_info.value("name", "")));
+      auto* tmp2 = new QTableWidgetItem(option_info["name"].toString());
       tmp2->setTextAlignment(Qt::AlignCenter);
       ui_->configurationDetailsTable->setItem(row, 2, tmp2);
 
-      auto* tmp3 = new QTableWidgetItem(
-          QString::fromStdString(option_info.value("description", "")));
+      auto* tmp3 = new QTableWidgetItem(option_info["description"].toString());
 
       tmp3->setTextAlignment(Qt::AlignLeft);
       ui_->configurationDetailsTable->setItem(row, 3, tmp3);
 
-      auto* tmp4 = new QTableWidgetItem(
-          QString::fromStdString(option_info.value("default_value", "")));
+      auto* tmp4 =
+          new QTableWidgetItem(option_info["default_value"].toString());
       tmp4->setTextAlignment(Qt::AlignLeft);
       ui_->configurationDetailsTable->setItem(row, 4, tmp4);
 
-      auto* tmp5 = new QTableWidgetItem(
-          QString::fromStdString(option_info.value("value", "")));
+      auto* tmp5 = new QTableWidgetItem(option_info["value"].toString());
       tmp5->setTextAlignment(Qt::AlignLeft);
       ui_->configurationDetailsTable->setItem(row, 5, tmp5);
 
diff --git a/src/ui/dialog/import_export/KeyServerImportDialog.cpp b/src/ui/dialog/import_export/KeyServerImportDialog.cpp
index 313c2ed1..f3213dc0 100644
--- a/src/ui/dialog/import_export/KeyServerImportDialog.cpp
+++ b/src/ui/dialog/import_export/KeyServerImportDialog.cpp
@@ -37,6 +37,7 @@
 #include "core/function/gpg/GpgKeyImportExporter.h"
 #include "ui/UISignalStation.h"
 #include "ui/struct/SettingsObject.h"
+#include "ui/struct/settings/KeyServerSO.h"
 #include "ui/thread/KeyServerImportTask.h"
 #include "ui/thread/KeyServerSearchTask.h"
 
@@ -126,25 +127,12 @@ auto KeyServerImportDialog::create_combo_box() -> QComboBox* {
   combo_box->setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Preferred);
 
   try {
-    SettingsObject key_server_json("key_server");
-
-    const auto key_server_list =
-        key_server_json.Check("server_list", nlohmann::json::array());
-
+    KeyServerSO key_server(SettingsObject("general_settings_state"));
+    const auto& key_server_list = key_server.server_list;
     for (const auto& key_server : key_server_list) {
-      const auto key_server_str = key_server.get<std::string>();
-      combo_box->addItem(key_server_str.c_str());
-    }
-
-    size_t default_key_server_index =
-        key_server_json.Check("default_server", 0);
-    if (default_key_server_index >= key_server_list.size()) {
-      throw std::runtime_error("default_server index out of range");
+      combo_box->addItem(key_server);
     }
-    auto default_key_server =
-        key_server_list[default_key_server_index].get<std::string>();
-
-    combo_box->setCurrentText(default_key_server.c_str());
+    combo_box->setCurrentText(key_server.GetTargetServer());
   } catch (...) {
     GF_UI_LOG_ERROR("setting operation error", "server_list", "default_server");
   }
@@ -401,29 +389,8 @@ void KeyServerImportDialog::SlotImport(const KeyIdArgsListPtr& keys) {
     target_keyserver = key_server_combo_box_->currentText();
   }
   if (target_keyserver.isEmpty()) {
-    try {
-      SettingsObject key_server_json("key_server");
-      const auto key_server_list =
-          key_server_json.Check("server_list", nlohmann::json::array());
-
-      size_t default_key_server_index =
-          key_server_json.Check("default_server", 0);
-      if (default_key_server_index >= key_server_list.size()) {
-        throw std::runtime_error("default_server index out of range");
-      }
-      auto default_key_server =
-          key_server_list[default_key_server_index].get<std::string>();
-
-      target_keyserver = QString::fromStdString(default_key_server);
-    } catch (...) {
-      GF_UI_LOG_ERROR("setting operation error", "server_list",
-                      "default_server");
-      QMessageBox::critical(
-          nullptr, _("Default Keyserver Not Found"),
-          _("Cannot read default keyserver from your settings, "
-            "please set a default keyserver first"));
-      return;
-    }
+    KeyServerSO key_server(SettingsObject("general_settings_state"));
+    target_keyserver = key_server.GetTargetServer();
   }
   std::vector<QString> key_ids;
   for (const auto& key_id : *keys) {
diff --git a/src/ui/dialog/import_export/KeyUploadDialog.cpp b/src/ui/dialog/import_export/KeyUploadDialog.cpp
index 4d36654e..3fdbc629 100644
--- a/src/ui/dialog/import_export/KeyUploadDialog.cpp
+++ b/src/ui/dialog/import_export/KeyUploadDialog.cpp
@@ -37,6 +37,7 @@
 #include "core/utils/GpgUtils.h"
 #include "ui/UserInterfaceUtils.h"
 #include "ui/struct/SettingsObject.h"
+#include "ui/struct/settings/KeyServerSO.h"
 
 namespace GpgFrontend::UI {
 
@@ -85,33 +86,8 @@ void KeyUploadDialog::SlotUpload() {
 
 void KeyUploadDialog::slot_upload_key_to_server(
     const GpgFrontend::GFBuffer& keys_data) {
-  QString target_keyserver;
-
-  try {
-    SettingsObject key_server_json("key_server");
-
-    const auto key_server_list =
-        key_server_json.Check("server_list", nlohmann::json::array());
-
-    size_t default_key_server_index =
-        key_server_json.Check("default_server", 0);
-    if (default_key_server_index >= key_server_list.size()) {
-      throw std::runtime_error("default_server index out of range");
-    }
-
-    target_keyserver = QString::fromStdString(
-        key_server_list[default_key_server_index].get<std::string>());
-
-    GF_UI_LOG_DEBUG("set target key server to default key server: {}",
-                    target_keyserver);
-
-  } catch (...) {
-    GF_UI_LOG_ERROR(_("Cannot read default_keyserver From Settings"));
-    QMessageBox::critical(nullptr, _("Default Keyserver Not Found"),
-                          _("Cannot read default keyserver from your settings, "
-                            "please set a default keyserver first"));
-    return;
-  }
+  KeyServerSO key_server(SettingsObject("general_settings_state"));
+  auto target_keyserver = key_server.GetTargetServer();
 
   QUrl req_url(target_keyserver + "/pks/add");
   auto* qnam = new QNetworkAccessManager(this);
diff --git a/src/ui/dialog/settings/SettingsAppearance.cpp b/src/ui/dialog/settings/SettingsAppearance.cpp
index 6ce04f45..b1843388 100644
--- a/src/ui/dialog/settings/SettingsAppearance.cpp
+++ b/src/ui/dialog/settings/SettingsAppearance.cpp
@@ -28,14 +28,15 @@
 
 #include "SettingsAppearance.h"
 
+#include "core/utils/MemoryUtils.h"
 #include "ui/struct/SettingsObject.h"
+#include "ui/struct/settings/AppearanceSO.h"
 #include "ui_AppearanceSettings.h"
 
 namespace GpgFrontend::UI {
 
 AppearanceTab::AppearanceTab(QWidget* parent)
-    : QWidget(parent),
-      ui_(GpgFrontend::SecureCreateSharedObject<Ui_AppearanceSettings>()) {
+    : QWidget(parent), ui_(SecureCreateSharedObject<Ui_AppearanceSettings>()) {
   ui_->setupUi(this);
 
   ui_->iconSizeBox->setTitle(_("Icon Size"));
@@ -73,14 +74,10 @@ AppearanceTab::AppearanceTab(QWidget* parent)
 }
 
 void AppearanceTab::SetSettings() {
-  SettingsObject general_settings_state("general_settings_state");
-
-  int const width =
-      general_settings_state.Check("icon_size").Check("width", 24);
-  int const height =
-      general_settings_state.Check("icon_size").Check("height", 24);
+  AppearanceSO appearance(SettingsObject("general_settings_state"));
 
-  auto icon_size = QSize(width, height);
+  auto icon_size =
+      QSize(appearance.tool_bar_icon_width, appearance.tool_bar_icon_height);
 
   switch (icon_size.width()) {
     case 12:
@@ -92,14 +89,12 @@ void AppearanceTab::SetSettings() {
     case 32:
       ui_->largeRadioButton->setChecked(true);
       break;
+    default:
+      ui_->smallRadioButton->setChecked(true);
+      break;
   }
 
-  // icon_style
-  int const s_icon_style =
-      general_settings_state.Check("icon_style", Qt::ToolButtonTextUnderIcon);
-  auto icon_style = static_cast<Qt::ToolButtonStyle>(s_icon_style);
-
-  switch (icon_style) {
+  switch (appearance.tool_bar_button_style) {
     case Qt::ToolButtonTextOnly:
       ui_->justTextRadioButton->setChecked(true);
       break;
@@ -113,18 +108,17 @@ void AppearanceTab::SetSettings() {
       break;
   }
 
-  bool const window_save = general_settings_state.Check("window_save", true);
-  if (window_save) ui_->windowStateCheckBox->setCheckState(Qt::Checked);
+  if (appearance.save_window_state) {
+    ui_->windowStateCheckBox->setCheckState(Qt::Checked);
+  }
 
-  auto info_board_info_font_size =
-      general_settings_state.Check("info_board").Check("font_size", 10);
+  auto info_board_info_font_size = appearance.info_board_font_size;
   if (info_board_info_font_size < 9 || info_board_info_font_size > 18) {
     info_board_info_font_size = 10;
   }
   ui_->fontSizeInformationBoardSpinBox->setValue(info_board_info_font_size);
 
-  auto text_editor_info_font_size =
-      general_settings_state.Check("text_editor").Check("font_size", 10);
+  auto text_editor_info_font_size = appearance.text_editor_font_size;
   if (text_editor_info_font_size < 9 || text_editor_info_font_size > 18) {
     text_editor_info_font_size = 10;
   }
@@ -133,6 +127,7 @@ void AppearanceTab::SetSettings() {
 
 void AppearanceTab::ApplySettings() {
   SettingsObject general_settings_state("general_settings_state");
+  AppearanceSO appearance(general_settings_state);
 
   int icon_size = 24;
   switch (icon_size_group_->checkedId()) {
@@ -147,8 +142,8 @@ void AppearanceTab::ApplySettings() {
       break;
   }
 
-  general_settings_state["icon_size"]["width"] = icon_size;
-  general_settings_state["icon_size"]["height"] = icon_size;
+  appearance.tool_bar_icon_height = icon_size;
+  appearance.tool_bar_icon_width = icon_size;
 
   auto icon_style = Qt::ToolButtonTextUnderIcon;
   switch (icon_style_group_->checkedId()) {
@@ -161,17 +156,19 @@ void AppearanceTab::ApplySettings() {
     case 3:
       icon_style = Qt::ToolButtonTextUnderIcon;
       break;
+    default:
+      icon_style = Qt::ToolButtonTextOnly;
+      break;
   }
+  appearance.tool_bar_button_style = icon_style;
 
-  general_settings_state["icon_style"] = icon_style;
-
-  general_settings_state["window_save"] = ui_->windowStateCheckBox->isChecked();
-
-  general_settings_state["info_board"]["font_size"] =
+  appearance.save_window_state = ui_->windowStateCheckBox->isChecked();
+  appearance.info_board_font_size =
       ui_->fontSizeInformationBoardSpinBox->value();
-
-  general_settings_state["text_editor"]["font_size"] =
+  appearance.text_editor_font_size =
       ui_->fontSizeTextEditorLabelSpinBox->value();
+
+  general_settings_state.Store(appearance.ToJson());
 }
 
 }  // namespace GpgFrontend::UI
diff --git a/src/ui/dialog/settings/SettingsKeyServer.cpp b/src/ui/dialog/settings/SettingsKeyServer.cpp
index 922ca230..83e3758b 100644
--- a/src/ui/dialog/settings/SettingsKeyServer.cpp
+++ b/src/ui/dialog/settings/SettingsKeyServer.cpp
@@ -34,6 +34,7 @@
 #include "core/thread/Task.h"
 #include "core/thread/TaskRunnerGetter.h"
 #include "ui/struct/SettingsObject.h"
+#include "ui/struct/settings/KeyServerSO.h"
 #include "ui/thread/ListedKeyServerTestTask.h"
 #include "ui_KeyServerSettings.h"
 
@@ -118,32 +119,18 @@ KeyserverTab::KeyserverTab(QWidget* parent)
 }
 
 void KeyserverTab::SetSettings() {
-  try {
-    SettingsObject key_server_json("key_server");
+  KeyServerSO key_server(SettingsObject("key_server"));
 
-    const auto key_server_list =
-        key_server_json.Check("server_list", nlohmann::json::array());
-
-    for (const auto& key_server : key_server_list) {
-      const auto key_server_str = key_server.get<std::string>();
-      this->key_server_str_list_.append(key_server_str.c_str());
-    }
-
-    size_t default_key_server_index =
-        key_server_json.Check("default_server", 0);
-    if (default_key_server_index >= key_server_list.size()) {
-      throw std::runtime_error("default_server index out of range");
-    }
-    const auto default_key_server =
-        key_server_list[default_key_server_index].get<std::string>();
+  if (key_server.server_list.empty()) key_server.ResetDefaultServerList();
+  for (const auto& key_server : key_server.server_list) {
+    this->key_server_str_list_.append(key_server);
+  }
 
-    if (!key_server_str_list_.contains(default_key_server.c_str())) {
-      key_server_str_list_.append(default_key_server.c_str());
-    }
-    default_key_server_ = QString::fromStdString(default_key_server);
-  } catch (const std::exception& e) {
-    GF_UI_LOG_ERROR("Error reading key-server settings: ", e.what());
+  const auto default_key_server = key_server.GetTargetServer();
+  if (!key_server_str_list_.contains(default_key_server)) {
+    key_server_str_list_.append(default_key_server);
   }
+  default_key_server_ = default_key_server;
 }
 
 void KeyserverTab::slot_add_key_server() {
@@ -170,26 +157,26 @@ void KeyserverTab::slot_add_key_server() {
           "that want to add it into the keyserver list?"),
         QMessageBox::Ok | QMessageBox::Cancel);
 
-    if (ret == QMessageBox::Cancel)
-      return;
-    else
-      key_server_str_list_.append(ui_->addKeyServerEdit->text());
+    if (ret == QMessageBox::Cancel) return;
+    key_server_str_list_.append(ui_->addKeyServerEdit->text());
   }
   slot_refresh_table();
 }
 
 void KeyserverTab::ApplySettings() {
   SettingsObject key_server_json("key_server");
-  key_server_json["server_list"] = nlohmann::json::array();
-  auto& key_server_list = key_server_json["server_list"];
+  KeyServerSO key_server;
 
+  auto& key_server_list = key_server.server_list;
   const auto list_size = key_server_str_list_.size();
   for (int i = 0; i < list_size; i++) {
     const auto key_server = key_server_str_list_[i];
-    if (default_key_server_ == key_server)
+    if (default_key_server_ == key_server) {
       key_server_json["default_server"] = i;
-    key_server_list.insert(key_server_list.end(), key_server.toStdString());
+    }
+    key_server_list << key_server;
   }
+  key_server_json.Store(key_server.ToJson());
 }
 
 void KeyserverTab::slot_refresh_table() {
diff --git a/src/ui/main_window/GeneralMainWindow.cpp b/src/ui/main_window/GeneralMainWindow.cpp
index ad2f061a..2eb9f2a4 100644
--- a/src/ui/main_window/GeneralMainWindow.cpp
+++ b/src/ui/main_window/GeneralMainWindow.cpp
@@ -28,9 +28,13 @@
 
 #include "GeneralMainWindow.h"
 
-#include <utility>
-
 #include "ui/struct/SettingsObject.h"
+#include "ui/struct/settings/AppearanceSO.h"
+#include "ui/struct/settings/WindowStateSO.h"
+
+namespace GpgFrontend::UI {
+
+class GeneralWindowState {};
 
 GpgFrontend::UI::GeneralMainWindow::GeneralMainWindow(QString name,
                                                       QWidget *parent)
@@ -50,30 +54,19 @@ void GpgFrontend::UI::GeneralMainWindow::closeEvent(QCloseEvent *event) {
 
 void GpgFrontend::UI::GeneralMainWindow::slot_restore_settings() noexcept {
   try {
-    SettingsObject general_windows_state(name_ + "_state");
+    WindowStateSO window_state(SettingsObject(name_ + "_state"));
 
-    QString window_state = QString::fromStdString(general_windows_state.Check(
-        "window_state", saveState().toBase64().toStdString()));
-    GF_UI_LOG_DEBUG("restore main window state: {}", window_state);
+    GF_UI_LOG_DEBUG("restore main window state: {}",
+                    window_state.window_state_data);
 
     // state sets pos & size of dock-widgets
-    this->restoreState(QByteArray::fromBase64(window_state.toUtf8()));
-
-    bool window_save = general_windows_state.Check("window_save", true);
-
-    // Restore window size & location
-    if (window_save) {
-      int x = general_windows_state.Check("window_pos").Check("x", 100);
-      int y = general_windows_state.Check("window_pos").Check("y", 100);
-
-      pos_ = {x, y};
-
-      int width =
-          general_windows_state.Check("window_size").Check("width", 800);
-      int height =
-          general_windows_state.Check("window_size").Check("height", 450);
+    this->restoreState(
+        QByteArray::fromBase64(window_state.window_state_data.toUtf8()));
 
-      size_ = {width, height};
+    // restore window size & location
+    if (window_state.window_save) {
+      pos_ = {window_state.x, window_state.y};
+      size_ = {window_state.width, window_state.height};
 
       if (this->parent() != nullptr) {
         GF_UI_LOG_DEBUG("parent address: {}",
@@ -114,21 +107,14 @@ void GpgFrontend::UI::GeneralMainWindow::slot_restore_settings() noexcept {
     }
 
     // appearance
-    SettingsObject general_settings_state("general_settings_state");
+    AppearanceSO appearance(SettingsObject("general_settings_state"));
 
-    int width = general_settings_state.Check("icon_size").Check("width", 24);
-    int height = general_settings_state.Check("icon_size").Check("height", 24);
-    GF_UI_LOG_DEBUG("icon size: {} {}", width, height);
-
-    icon_size_ = {width, height};
-    font_size_ = general_settings_state.Check("font_size", 10);
+    icon_size_ = {appearance.tool_bar_icon_width,
+                  appearance.tool_bar_icon_height};
+    font_size_ = appearance.info_board_font_size;
 
     this->setIconSize(icon_size_);
-
-    // icon_style
-    int s_icon_style =
-        general_settings_state.Check("icon_style", Qt::ToolButtonTextUnderIcon);
-    this->setToolButtonStyle(static_cast<Qt::ToolButtonStyle>(s_icon_style));
+    this->setToolButtonStyle(appearance.tool_bar_button_style);
     icon_style_ = toolButtonStyle();
 
   } catch (...) {
@@ -141,32 +127,22 @@ void GpgFrontend::UI::GeneralMainWindow::slot_save_settings() noexcept {
     GF_UI_LOG_DEBUG("save main window state, name: {}", name_);
     SettingsObject general_windows_state(name_ + "_state");
 
-    // window position and size
-    general_windows_state["window_state"] =
-        saveState().toBase64().toStdString();
-    general_windows_state["window_pos"]["x"] = pos().x();
-    general_windows_state["window_pos"]["y"] = pos().y();
-
-    // update size of current dialog
+    // update geo of current dialog
     size_ = this->size();
+    pos_ = this->pos();
 
-    general_windows_state["window_size"]["width"] = size_.width();
-    general_windows_state["window_size"]["height"] = size_.height();
-    general_windows_state["window_save"] = true;
-
-    SettingsObject general_settings_state("general_settings_state");
-
-    // icon size
-    general_settings_state["icon_size"]["width"] = icon_size_.width();
-    general_settings_state["icon_size"]["height"] = icon_size_.height();
-
-    // font size
-    general_settings_state["font_size"] = font_size_;
-
-    // tool button style
-    general_settings_state["icon_style"] = this->toolButtonStyle();
+    WindowStateSO window_state;
+    window_state.x = pos_.x();
+    window_state.y = pos_.y();
+    window_state.width = size_.width();
+    window_state.height = size_.height();
+    window_state.window_save = true;
+    window_state.window_state_data = this->saveState().toBase64();
 
+    general_windows_state.Store(window_state.Json());
   } catch (...) {
     GF_UI_LOG_ERROR("gernal main window: {}, caught exception", name_);
   }
 }
+
+}  // namespace GpgFrontend::UI
\ No newline at end of file
diff --git a/src/ui/main_window/MainWindow.cpp b/src/ui/main_window/MainWindow.cpp
index e8280e93..0faa7379 100644
--- a/src/ui/main_window/MainWindow.cpp
+++ b/src/ui/main_window/MainWindow.cpp
@@ -37,6 +37,7 @@
 #include "ui/UISignalStation.h"
 #include "ui/main_window/GeneralMainWindow.h"
 #include "ui/struct/SettingsObject.h"
+#include "ui/struct/settings/KeyServerSO.h"
 #include "ui/widgets/KeyList.h"
 
 namespace GpgFrontend::UI {
@@ -190,21 +191,17 @@ void MainWindow::restore_settings() {
   try {
     GF_UI_LOG_DEBUG("restore settings key_server");
 
-    SettingsObject key_server_json("key_server");
-    if (!key_server_json.contains("server_list") ||
-        key_server_json["server_list"].empty()) {
-      key_server_json["server_list"] = {"https://keyserver.ubuntu.com",
-                                        "https://keys.openpgp.org"};
-    }
-    if (!key_server_json.contains("default_server")) {
-      key_server_json["default_server"] = 0;
-    }
+    KeyServerSO key_server(SettingsObject("key_server"));
+
+    if (key_server.server_list.empty()) key_server.ResetDefaultServerList();
+    if (key_server.default_server < 0) key_server.default_server = 0;
 
     auto &settings = GlobalSettingStation::GetInstance().GetMainSettings();
 
     if (!settings.exists("general") ||
-        settings.lookup("general").getType() != libconfig::Setting::TypeGroup)
+        settings.lookup("general").getType() != libconfig::Setting::TypeGroup) {
       settings.add("general", libconfig::Setting::TypeGroup);
+    }
 
     auto &general = settings["general"];
 
@@ -233,25 +230,30 @@ void MainWindow::restore_settings() {
 }
 
 void MainWindow::recover_editor_unsaved_pages_from_cache() {
-  auto unsaved_page_array =
+  auto json_data =
       CacheManager::GetInstance().LoadCache("editor_unsaved_pages");
 
-  if (!unsaved_page_array.is_array() || unsaved_page_array.empty()) {
+  if (json_data.isEmpty() || !json_data.isArray()) {
     return;
   }
 
   GF_UI_LOG_DEBUG("plan ot recover unsaved page from cache, page array: {}",
-                  unsaved_page_array.dump());
+                  json_data.toJson());
 
   bool first = true;
 
-  for (auto &unsaved_page_json : unsaved_page_array) {
+  QJsonArray unsaved_page_array = json_data.array();
+  for (const auto &value_ref : unsaved_page_array) {
+    if (!value_ref.isObject()) continue;
+    auto unsaved_page_json = value_ref.toObject();
+
     if (!unsaved_page_json.contains("title") ||
         !unsaved_page_json.contains("content")) {
       continue;
     }
-    QString title = QString::fromStdString(unsaved_page_json["title"]);
-    QString content = QString::fromStdString(unsaved_page_json["content"]);
+
+    QString title = unsaved_page_json["title"].toString();
+    QString content = unsaved_page_json["content"].toString();
 
     GF_UI_LOG_DEBUG(
         "recovering unsaved page from cache, page title: {}, content size",
@@ -294,7 +296,7 @@ void MainWindow::closeEvent(QCloseEvent *event) {
   if (event->isAccepted()) {
     // clear cache of unsaved page
     CacheManager::GetInstance().SaveCache("editor_unsaved_pages",
-                                          nlohmann::json::array(), true);
+                                          QJsonDocument(QJsonArray()), true);
 
     // clear password from memory
     //  GpgContext::GetInstance().clearPasswordCache();
diff --git a/src/ui/main_window/MainWindowSlotUI.cpp b/src/ui/main_window/MainWindowSlotUI.cpp
index 772204b1..2c7a6f62 100644
--- a/src/ui/main_window/MainWindowSlotUI.cpp
+++ b/src/ui/main_window/MainWindowSlotUI.cpp
@@ -34,6 +34,7 @@
 #include "ui/function/RaisePinentry.h"
 #include "ui/main_window/KeyMgmt.h"
 #include "ui/struct/SettingsObject.h"
+#include "ui/struct/settings/AppearanceSO.h"
 
 namespace GpgFrontend::UI {
 
@@ -100,30 +101,25 @@ void MainWindow::slot_disable_tab_actions(int number) {
 }
 
 void MainWindow::slot_open_settings_dialog() {
-  auto dialog = new SettingsDialog(this);
+  auto* dialog = new SettingsDialog(this);
 
   connect(dialog, &SettingsDialog::finished, this, [&]() -> void {
-    SettingsObject general_settings_state("general_settings_state");
+    AppearanceSO appearance(SettingsObject("general_settings_state"));
+    GF_UI_LOG_DEBUG("tool bar icon_size: {}, {}",
+                    appearance.tool_bar_icon_width,
+                    appearance.tool_bar_icon_height);
 
-    int width = general_settings_state.Check("icon_size").Check("width", 24);
-    int height = general_settings_state.Check("icon_size").Check("height", 24);
-    GF_UI_LOG_DEBUG("icon_size: {} {}", width, height);
-
-    general_settings_state.Check("info_font_size", 10);
-
-    // icon_style
-    int s_icon_style =
-        general_settings_state.Check("icon_style", Qt::ToolButtonTextUnderIcon);
-    auto icon_style = static_cast<Qt::ToolButtonStyle>(s_icon_style);
-    this->setToolButtonStyle(icon_style);
-    import_button_->setToolButtonStyle(icon_style);
+    this->setToolButtonStyle(appearance.tool_bar_button_style);
+    import_button_->setToolButtonStyle(appearance.tool_bar_button_style);
 
     // icons ize
-    this->setIconSize(QSize(width, height));
-    import_button_->setIconSize(QSize(width, height));
+    this->setIconSize(
+        QSize(appearance.tool_bar_icon_width, appearance.tool_bar_icon_height));
+    import_button_->setIconSize(
+        QSize(appearance.tool_bar_icon_width, appearance.tool_bar_icon_height));
 
     // restart mainwindow if necessary
-    if (get_restart_needed()) {
+    if (get_restart_needed() != 0) {
       if (edit_->MaybeSaveAnyTab()) {
         save_settings();
         emit SignalRestartApplication(get_restart_needed());
diff --git a/src/ui/struct/CacheObject.cpp b/src/ui/struct/CacheObject.cpp
new file mode 100644
index 00000000..5413a80e
--- /dev/null
+++ b/src/ui/struct/CacheObject.cpp
@@ -0,0 +1,48 @@
+/**
+ * Copyright (C) 2021 Saturneric <[email protected]>
+ *
+ * This file is part of GpgFrontend.
+ *
+ * GpgFrontend 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 3 of the License, or
+ * (at your option) any later version.
+ *
+ * GpgFrontend 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 GpgFrontend. If not, see <https://www.gnu.org/licenses/>.
+ *
+ * The initial version of the source code is inherited from
+ * the gpg4usb project, which is under GPL-3.0-or-later.
+ *
+ * All the source code of GpgFrontend was modified and released by
+ * Saturneric <[email protected]> starting on May 12, 2021.
+ *
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ *
+ */
+
+#include "CacheObject.h"
+
+#include <utility>
+
+#include "core/function/CacheManager.h"
+
+namespace GpgFrontend::UI {
+
+CacheObject::CacheObject(QString cache_name)
+    : cache_name_(std::move(cache_name)) {
+  GF_UI_LOG_DEBUG("loading cache from: {}", this->cache_name_);
+  this->QJsonDocument::operator=(
+      CacheManager::GetInstance().LoadCache(cache_name_));
+}
+
+CacheObject::~CacheObject() {
+  CacheManager::GetInstance().SaveCache(cache_name_, *this);
+}
+
+}  // namespace GpgFrontend::UI
\ No newline at end of file
diff --git a/src/ui/struct/CacheObject.h b/src/ui/struct/CacheObject.h
new file mode 100644
index 00000000..ae8aa056
--- /dev/null
+++ b/src/ui/struct/CacheObject.h
@@ -0,0 +1,52 @@
+/**
+ * Copyright (C) 2021 Saturneric <[email protected]>
+ *
+ * This file is part of GpgFrontend.
+ *
+ * GpgFrontend 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 3 of the License, or
+ * (at your option) any later version.
+ *
+ * GpgFrontend 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 GpgFrontend. If not, see <https://www.gnu.org/licenses/>.
+ *
+ * The initial version of the source code is inherited from
+ * the gpg4usb project, which is under GPL-3.0-or-later.
+ *
+ * All the source code of GpgFrontend was modified and released by
+ * Saturneric <[email protected]> starting on May 12, 2021.
+ *
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ *
+ */
+
+#pragma once
+
+namespace GpgFrontend::UI {
+
+class CacheObject : public QJsonDocument {
+ public:
+  /**
+   * @brief Construct a new Cache Object object
+   *
+   * @param cache_name
+   */
+  explicit CacheObject(QString cache_name);
+
+  /**
+   * @brief Destroy the Cache Object object
+   *
+   */
+  ~CacheObject();
+
+ private:
+  QString cache_name_;  ///<
+};
+
+}  // namespace GpgFrontend::UI
\ No newline at end of file
diff --git a/src/ui/struct/SettingsObject.cpp b/src/ui/struct/SettingsObject.cpp
index d03a4fe3..cc5e85bf 100644
--- a/src/ui/struct/SettingsObject.cpp
+++ b/src/ui/struct/SettingsObject.cpp
@@ -28,81 +28,42 @@
 
 #include "SettingsObject.h"
 
-nlohmann::json& GpgFrontend::UI::SettingsObject::Check(
-    const QString& key, const nlohmann::json& default_value) {
-  // check if the self null
-  if (this->nlohmann::json::is_null()) {
-    GF_UI_LOG_DEBUG("settings object is null, creating new one");
-    this->nlohmann::json::operator=(nlohmann::json::object());
-  }
+#include "core/function/DataObjectOperator.h"
 
-  try {
-    auto s_key = key.toStdString();
-    if (!this->nlohmann::json::contains(s_key) ||
-        this->nlohmann::json::at(s_key).is_null() ||
-        this->nlohmann::json::at(s_key).type_name() !=
-            default_value.type_name()) {
-      GF_UI_LOG_DEBUG("added missing key: {}", key);
-      if (default_value.is_null()) {
-        GF_UI_LOG_WARN("default value is null, using empty object");
-        this->nlohmann::json::operator[](s_key) = nlohmann::json::object();
-      } else {
-        this->nlohmann::json::operator[](s_key) = default_value;
-      }
-    }
-    return this->nlohmann::json::at(s_key);
-  } catch (nlohmann::json::exception& e) {
-    GF_UI_LOG_ERROR(e.what());
-    throw e;
-  }
-}
-
-GpgFrontend::UI::SettingsObject GpgFrontend::UI::SettingsObject::Check(
-    const QString& key) {
-  // check if the self null
-  if (this->nlohmann::json::is_null()) {
-    GF_UI_LOG_DEBUG("settings object is null, creating new one");
-    this->nlohmann::json::operator=(nlohmann::json::object());
-  }
+namespace GpgFrontend::UI {
 
-  auto s_key = key.toStdString();
-  if (!nlohmann::json::contains(s_key) ||
-      this->nlohmann::json::at(s_key).is_null() ||
-      this->nlohmann::json::at(s_key).type() !=
-          nlohmann::json::value_t::object) {
-    GF_UI_LOG_DEBUG("added missing key: {}", key);
-    this->nlohmann::json::operator[](s_key) = nlohmann::json::object();
-  }
-  return SettingsObject{nlohmann::json::operator[](s_key), false};
-}
-
-GpgFrontend::UI::SettingsObject::SettingsObject(QString settings_name)
+SettingsObject::SettingsObject(QString settings_name)
     : settings_name_(std::move(settings_name)) {
   try {
     GF_UI_LOG_DEBUG("loading settings from: {}", this->settings_name_);
-    auto _json_optional =
-        GpgFrontend::DataObjectOperator::GetInstance().GetDataObject(
-            settings_name_);
+    auto json_optional =
+        DataObjectOperator::GetInstance().GetDataObject(settings_name_);
 
-    if (_json_optional.has_value()) {
+    if (json_optional.has_value() && json_optional->isObject()) {
       GF_UI_LOG_DEBUG("settings object: {} loaded.", settings_name_);
-      nlohmann::json::operator=(_json_optional.value());
+      QJsonObject::operator=(json_optional.value().object());
     } else {
       GF_UI_LOG_DEBUG("settings object: {} not found.", settings_name_);
-      nlohmann::json::operator=({});
+      QJsonObject::operator=({});
     }
 
   } catch (std::exception& e) {
-    GF_UI_LOG_ERROR(e.what());
+    GF_UI_LOG_ERROR("load setting object error: {}", e.what());
   }
 }
 
-GpgFrontend::UI::SettingsObject::SettingsObject(nlohmann::json _sub_json, bool)
-    : nlohmann::json(std::move(_sub_json)) {}
+SettingsObject::SettingsObject(QJsonObject sub_json)
+    : QJsonObject(std::move(sub_json)) {}
 
-GpgFrontend::UI::SettingsObject::~SettingsObject() {
+SettingsObject::~SettingsObject() {
   if (!settings_name_.isEmpty()) {
-    GpgFrontend::DataObjectOperator::GetInstance().SaveDataObj(settings_name_,
-                                                               *this);
+    DataObjectOperator::GetInstance().SaveDataObj(settings_name_,
+                                                  QJsonDocument(*this));
   }
-}
\ No newline at end of file
+}
+
+void SettingsObject::Store(const QJsonObject& json) {
+  auto* parent = (static_cast<QJsonObject*>(this));
+  *parent = json;
+}
+}  // namespace GpgFrontend::UI
\ No newline at end of file
diff --git a/src/ui/struct/SettingsObject.h b/src/ui/struct/SettingsObject.h
index 25e459ac..a9e5819f 100644
--- a/src/ui/struct/SettingsObject.h
+++ b/src/ui/struct/SettingsObject.h
@@ -28,18 +28,14 @@
 
 #pragma once
 
-#include <utility>
-
-#include "core/function/DataObjectOperator.h"
-
 namespace GpgFrontend::UI {
 
 /**
  * @brief The SettingsObject class
- * This class is used to store settings for the application securely.
+ * This class is used to store data for the application securely.
  *
  */
-class SettingsObject : public nlohmann::json {
+class SettingsObject : public QJsonObject {
  public:
   /**
    * @brief Construct a new Settings Object object
@@ -53,7 +49,7 @@ class SettingsObject : public nlohmann::json {
    *
    * @param _sub_json
    */
-  explicit SettingsObject(nlohmann::json _sub_json, bool);
+  explicit SettingsObject(QJsonObject sub_json);
 
   /**
    * @brief Destroy the Settings Object object
@@ -64,20 +60,8 @@ class SettingsObject : public nlohmann::json {
   /**
    * @brief
    *
-   * @param key
-   * @param default_value
-   * @return nlohmann::json&
-   */
-  nlohmann::json& Check(const QString& key,
-                        const nlohmann::json& default_value);
-
-  /**
-   * @brief
-   *
-   * @param key
-   * @return SettingsObject
    */
-  SettingsObject Check(const QString& key);
+  void Store(const QJsonObject&);
 
  private:
   QString settings_name_;  ///<
diff --git a/src/ui/struct/settings/AppearanceSO.h b/src/ui/struct/settings/AppearanceSO.h
new file mode 100644
index 00000000..25262f22
--- /dev/null
+++ b/src/ui/struct/settings/AppearanceSO.h
@@ -0,0 +1,77 @@
+/**
+ * Copyright (C) 2021 Saturneric <[email protected]>
+ *
+ * This file is part of GpgFrontend.
+ *
+ * GpgFrontend 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 3 of the License, or
+ * (at your option) any later version.
+ *
+ * GpgFrontend 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 GpgFrontend. If not, see <https://www.gnu.org/licenses/>.
+ *
+ * The initial version of the source code is inherited from
+ * the gpg4usb project, which is under GPL-3.0-or-later.
+ *
+ * All the source code of GpgFrontend was modified and released by
+ * Saturneric <[email protected]> starting on May 12, 2021.
+ *
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ *
+ */
+
+#pragma once
+
+namespace GpgFrontend::UI {
+
+struct AppearanceSO {
+  int text_editor_font_size = 12;
+  int info_board_font_size = 12;
+  int tool_bar_icon_width = 24;
+  int tool_bar_icon_height = 24;
+  Qt::ToolButtonStyle tool_bar_button_style = Qt::ToolButtonTextUnderIcon;
+
+  bool save_window_state;
+
+  explicit AppearanceSO(const QJsonObject& j) {
+    if (const auto v = j["text_editor_font_size"]; v.isDouble()) {
+      text_editor_font_size = v.toInt();
+    }
+    if (const auto v = j["info_board_font_size"]; v.isDouble()) {
+      info_board_font_size = v.toInt();
+    }
+    if (const auto v = j["tool_bar_icon_width"]; v.isDouble()) {
+      tool_bar_icon_width = v.toInt();
+    }
+    if (const auto v = j["tool_bar_icon_height"]; v.isDouble()) {
+      tool_bar_icon_height = v.toInt();
+    }
+    if (const auto v = j["tool_bar_button_style"]; v.isDouble()) {
+      tool_bar_button_style = static_cast<Qt::ToolButtonStyle>(v.toInt());
+    }
+
+    if (const auto v = j["save_window_state"]; v.isBool()) {
+      save_window_state = v.toBool();
+    }
+  }
+
+  [[nodiscard]] auto ToJson() const -> QJsonObject {
+    QJsonObject j;
+    j["text_editor_font_size"] = text_editor_font_size;
+    j["info_board_font_size"] = info_board_font_size;
+    j["tool_bar_icon_width"] = tool_bar_icon_width;
+    j["tool_bar_icon_height"] = tool_bar_icon_height;
+    j["tool_bar_button_style"] = tool_bar_button_style;
+
+    j["save_window_state"] = save_window_state;
+    return j;
+  }
+};
+
+}  // namespace GpgFrontend::UI
\ No newline at end of file
diff --git a/src/ui/struct/settings/KeyServerSO.h b/src/ui/struct/settings/KeyServerSO.h
new file mode 100644
index 00000000..3c9320d2
--- /dev/null
+++ b/src/ui/struct/settings/KeyServerSO.h
@@ -0,0 +1,79 @@
+/**
+ * Copyright (C) 2021 Saturneric <[email protected]>
+ *
+ * This file is part of GpgFrontend.
+ *
+ * GpgFrontend 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 3 of the License, or
+ * (at your option) any later version.
+ *
+ * GpgFrontend 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 GpgFrontend. If not, see <https://www.gnu.org/licenses/>.
+ *
+ * The initial version of the source code is inherited from
+ * the gpg4usb project, which is under GPL-3.0-or-later.
+ *
+ * All the source code of GpgFrontend was modified and released by
+ * Saturneric <[email protected]> starting on May 12, 2021.
+ *
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ *
+ */
+
+#pragma once
+
+namespace GpgFrontend::UI {
+
+struct KeyServerSO {
+  int default_server = 0;
+  QStringList server_list;
+
+  KeyServerSO() = default;
+
+  explicit KeyServerSO(const QJsonObject& j) {
+    if (const auto v = j["default_server"]; v.isDouble()) {
+      default_server = v.toInt();
+    }
+
+    if (const auto v = j["server_list"]; v.isArray()) {
+      const QJsonArray j_array = v.toArray();
+      server_list.reserve(j_array.size());
+      for (const auto& server : j_array) {
+        server_list.append(server.toString());
+      }
+    }
+
+    if (server_list.empty()) ResetDefaultServerList();
+  }
+
+  auto ToJson() -> QJsonObject {
+    QJsonObject j;
+    j["default_server"] = default_server;
+    auto j_array = QJsonArray();
+
+    for (const auto& s : server_list) {
+      j_array.push_back(s);
+    }
+    j["server_list"] = j_array;
+    return j;
+  }
+
+  auto GetTargetServer() -> QString {
+    if (server_list.empty()) this->ResetDefaultServerList();
+    if (default_server >= server_list.size()) default_server = 0;
+    return server_list[default_server];
+  }
+
+  void ResetDefaultServerList() {
+    server_list << "https://keyserver.ubuntu.com"
+                << "https://keys.openpgp.org";
+  }
+};
+
+}  // namespace GpgFrontend::UI
\ No newline at end of file
diff --git a/src/ui/struct/settings/WindowStateSO.h b/src/ui/struct/settings/WindowStateSO.h
new file mode 100644
index 00000000..3fa56f3c
--- /dev/null
+++ b/src/ui/struct/settings/WindowStateSO.h
@@ -0,0 +1,65 @@
+/**
+ * Copyright (C) 2021 Saturneric <[email protected]>
+ *
+ * This file is part of GpgFrontend.
+ *
+ * GpgFrontend 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 3 of the License, or
+ * (at your option) any later version.
+ *
+ * GpgFrontend 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 GpgFrontend. If not, see <https://www.gnu.org/licenses/>.
+ *
+ * The initial version of the source code is inherited from
+ * the gpg4usb project, which is under GPL-3.0-or-later.
+ *
+ * All the source code of GpgFrontend was modified and released by
+ * Saturneric <[email protected]> starting on May 12, 2021.
+ *
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ *
+ */
+
+#pragma once
+
+namespace GpgFrontend::UI {
+
+struct WindowStateSO {
+  bool window_save = false;
+  QString window_state_data;
+  int x = 100;
+  int y = 100;
+  int width = 400;
+  int height = 200;
+
+  WindowStateSO() = default;
+
+  explicit WindowStateSO(const QJsonObject &j) {
+    if (const auto v = j["window_save"]; v.isBool()) window_save = v.toBool();
+    if (const auto v = j["window_state_data"]; v.isString()) {
+      window_state_data = v.toString();
+    }
+    if (const auto v = j["x"]; v.isDouble()) x = v.toInt();
+    if (const auto v = j["y"]; v.isDouble()) y = v.toInt();
+    if (const auto v = j["width"]; v.isDouble()) width = v.toInt();
+    if (const auto v = j["height"]; v.isDouble()) height = v.toInt();
+  }
+
+  [[nodiscard]] auto Json() const -> QJsonObject {
+    QJsonObject j;
+    j["window_save"] = window_save;
+    j["window_state_data"] = window_state_data;
+    j["x"] = x;
+    j["y"] = y;
+    j["width"] = width;
+    j["height"] = height;
+    return j;
+  }
+};
+}  // namespace GpgFrontend::UI
\ No newline at end of file
diff --git a/src/ui/thread/KeyServerImportTask.cpp b/src/ui/thread/KeyServerImportTask.cpp
index 4e8a41db..cf5c6263 100644
--- a/src/ui/thread/KeyServerImportTask.cpp
+++ b/src/ui/thread/KeyServerImportTask.cpp
@@ -30,6 +30,7 @@
 
 #include "core/function/gpg/GpgKeyImportExporter.h"
 #include "ui/struct/SettingsObject.h"
+#include "ui/struct/settings/KeyServerSO.h"
 
 GpgFrontend::UI::KeyServerImportTask::KeyServerImportTask(
     QString keyserver_url, std::vector<QString> keyids)
@@ -40,27 +41,8 @@ GpgFrontend::UI::KeyServerImportTask::KeyServerImportTask(
   HoldOnLifeCycle(true);
 
   if (keyserver_url_.isEmpty()) {
-    try {
-      SettingsObject key_server_json("key_server");
-      const auto key_server_list =
-          key_server_json.Check("server_list", nlohmann::json::array());
-
-      size_t const default_key_server_index =
-          key_server_json.Check("default_server", 0);
-      if (default_key_server_index >= key_server_list.size()) {
-        throw std::runtime_error("default_server index out of range");
-      }
-      auto default_key_server =
-          key_server_list[default_key_server_index].get<std::string>();
-
-      keyserver_url_ = QString::fromStdString(default_key_server);
-    } catch (...) {
-      GF_UI_LOG_ERROR("setting operation error", "server_list",
-                      "default_server");
-      keyserver_url_ = "https://keys.openpgp.org";
-      return;
-    }
-
+    KeyServerSO key_server(SettingsObject("general_settings_state"));
+    keyserver_url_ = key_server.GetTargetServer();
     GF_UI_LOG_DEBUG("key server import task sets key server url: {}",
                     keyserver_url_);
   }
diff --git a/src/ui/widgets/InfoBoardWidget.cpp b/src/ui/widgets/InfoBoardWidget.cpp
index 26530f8d..bf3dba18 100644
--- a/src/ui/widgets/InfoBoardWidget.cpp
+++ b/src/ui/widgets/InfoBoardWidget.cpp
@@ -31,6 +31,7 @@
 #include "core/GpgModel.h"
 #include "ui/UISignalStation.h"
 #include "ui/struct/SettingsObject.h"
+#include "ui/struct/settings/AppearanceSO.h"
 #include "ui_InfoBoard.h"
 
 namespace GpgFrontend::UI {
@@ -81,12 +82,10 @@ void InfoBoardWidget::SetInfoBoard(const QString& text,
   status.setColor(QPalette::Text, color);
   ui_->infoBoard->setPalette(status);
 
-  SettingsObject general_settings_state("general_settings_state");
+  AppearanceSO appearance(SettingsObject("general_settings_state"));
 
   // info board font size
-  auto info_font_size =
-      general_settings_state.Check("info_board").Check("font_size", 10);
-  ui_->infoBoard->setFont(QFont("Times", info_font_size));
+  ui_->infoBoard->setFont(QFont("Times", appearance.info_board_font_size));
 }
 
 void InfoBoardWidget::SlotRefresh(const QString& text, InfoBoardStatus status) {
diff --git a/src/ui/widgets/PlainTextEditorPage.cpp b/src/ui/widgets/PlainTextEditorPage.cpp
index 0a4d9d1a..1a6978fe 100644
--- a/src/ui/widgets/PlainTextEditorPage.cpp
+++ b/src/ui/widgets/PlainTextEditorPage.cpp
@@ -28,8 +28,6 @@
 
 #include "PlainTextEditorPage.h"
 
-#include <sstream>
-#include <string>
 #include <utility>
 
 #include "core/function/CharsetOperator.h"
@@ -37,6 +35,7 @@
 #include "core/thread/Task.h"
 #include "core/thread/TaskRunnerGetter.h"
 #include "ui/struct/SettingsObject.h"
+#include "ui/struct/settings/AppearanceSO.h"
 #include "ui_PlainTextEditor.h"
 
 namespace GpgFrontend::UI {
@@ -50,13 +49,9 @@ PlainTextEditorPage::PlainTextEditorPage(QString file_path, QWidget *parent)
   ui_->textPage->setFocus();
   ui_->loadingLabel->setHidden(true);
 
-  // Front in same width
-  SettingsObject general_settings_state("general_settings_state");
-
   // font size
-  auto editor_font_size =
-      general_settings_state.Check("text_editor").Check("font_size", 10);
-  ui_->textPage->setFont(QFont("Courier", editor_font_size));
+  AppearanceSO appearance(SettingsObject("general_settings_state"));
+  ui_->textPage->setFont(QFont("Courier", appearance.text_editor_font_size));
 
   this->setAttribute(Qt::WA_DeleteOnClose);
 
diff --git a/src/ui/widgets/TextEdit.cpp b/src/ui/widgets/TextEdit.cpp
index e29184b8..0c5fb631 100644
--- a/src/ui/widgets/TextEdit.cpp
+++ b/src/ui/widgets/TextEdit.cpp
@@ -35,6 +35,7 @@
 #include "core/GpgModel.h"
 #include "core/function/CacheManager.h"
 #include "core/function/GlobalSettingStation.h"
+#include "ui/struct/CacheObject.h"
 
 namespace GpgFrontend::UI {
 
@@ -668,26 +669,24 @@ void TextEdit::slot_save_status_to_cache_for_revovery() {
     }
 
     auto raw_text = document->toRawText();
-    GF_UI_LOG_DEBUG("unsaved page index: {}, tab title: {} tab content: {}", i,
-                    tab_title, raw_text.size());
+    GF_UI_LOG_DEBUG("unsaved page index: {}, tab title: {}", i, tab_title);
     unsaved_pages.emplace_back(i, tab_title, raw_text);
   }
 
-  nlohmann::json unsaved_page_array = nlohmann::json::array();
+  CacheObject cache("editor_unsaved_pages");
+  QJsonArray unsaved_page_array;
   for (const auto& page : unsaved_pages) {
     const auto [index, title, content] = page;
 
-    nlohmann::json page_json;
+    QJsonObject page_json;
     page_json["index"] = index;
-    page_json["title"] = title.toStdString();
-    page_json["content"] = content.toStdString();
+    page_json["title"] = title;
+    page_json["content"] = content;
 
     unsaved_page_array.push_back(page_json);
   }
 
-  GF_UI_LOG_DEBUG("unsaved page json array: {}", unsaved_page_array.dump());
-  CacheManager::GetInstance().SaveCache("editor_unsaved_pages",
-                                        unsaved_page_array);
+  cache.setArray(unsaved_page_array);
 }
 
 }  // namespace GpgFrontend::UI