Add KeePass header check for testing remote download (#10910)

Author: t-h-e

share/translations/keepassxc_en.ts

@@ -2332,10 +2332,6 @@ removed from the database.</source>
         <source>Download failed with error: %1</source>
         <translation type="unfinished"></translation>
     </message>
-    <message>
-        <source>Download finished, but file %1 could not be found.</source>
-        <translation type="unfinished"></translation>
-    </message>
     <message>
         <source>Download successful.</source>
         <translation type="unfinished"></translation>
@@ -2368,6 +2364,14 @@ The command has to exit. In case of `sftp` as last command `exit` has to be sent
             </source>
         <translation type="unfinished"></translation>
     </message>
+    <message>
+        <source>Command finished, but downloaded file does not exist.</source>
+        <translation type="unfinished"></translation>
+    </message>
+    <message>
+        <source>Download finished, but file failed KeePass header check. File is not a KeePass file or it&apos;s an unsupported version</source>
+        <translation type="unfinished"></translation>
+    </message>
 </context>
 <context>
     <name>DatabaseTabWidget</name>

src/gui/remote/DatabaseSettingsWidgetRemote.cpp

@@ -18,6 +18,7 @@
 #include "DatabaseSettingsWidgetRemote.h"
 #include "ui_DatabaseSettingsWidgetRemote.h"
 
+#include "core/Database.h"
 #include "core/Global.h"
 #include "core/Metadata.h"
 
@@ -191,10 +192,24 @@ void DatabaseSettingsWidgetRemote::testDownload()
     }
 
     if (!QFile::exists(result.filePath)) {
-        m_ui->messageWidget->showMessage(tr("Download finished, but file %1 could not be found.").arg(result.filePath),
+        m_ui->messageWidget->showMessage(tr("Command finished, but downloaded file does not exist."),
+                                         MessageWidget::Error);
+        return;
+    }
+
+    if (!hasValidPublicHeaders(result.filePath)) {
+        m_ui->messageWidget->showMessage(tr("Download finished, but file failed KeePass header check. File is not a "
+                                            "KeePass file or it's an unsupported version"),
                                          MessageWidget::Error);
         return;
     }
 
     m_ui->messageWidget->showMessage(tr("Download successful."), MessageWidget::Positive);
+}
+
+bool DatabaseSettingsWidgetRemote::hasValidPublicHeaders(QString& filePath) {
+    // Read public headers
+    QString error;
+    QScopedPointer<Database> db(new Database());
+    return db->open(filePath, nullptr, &error);
 }

src/gui/remote/DatabaseSettingsWidgetRemote.h

@@ -56,6 +56,8 @@ private slots:
     QListWidgetItem* findItemByName(const QString& name);
     void clearFields();
 
+    bool hasValidPublicHeaders(QString& filePath);
+
     QScopedPointer<RemoteSettings> m_remoteSettings;
     const QScopedPointer<Ui::DatabaseSettingsWidgetRemote> m_ui;
     bool m_modified = false;