How to use a pre-populated sqlite database with qwebview?

Question

Is there a way to use a pre-populated sqlite database with a qwebview? I have a javascript application that makes use of that database.

I've enabled offline storage,

QWebSettings::globalSettings()->setAttribute(QWebSettings::OfflineStorageDatabaseEnabled, true);

set a confortable size to it

QWebSettings::setOfflineStorageDefaultQuota(20*1024*1024);

and set location:

QWebSettings::globalSettings()->setOfflineStoragePath(QStandardPaths::writableLocation(QStandardPaths::GenericDataLocation)+"/data/myapp");

Copying the database file from qrc resource file to that location doesn't do the trick;

QFile::copy(":/mydatabase.db" , QStandardPaths::writableLocation(QStandardPaths::GenericDataLocation)+"/data/myapp/mydatabase.db");

how to proceed?

Thank you.

Answer 1

Verify if file in destination path does not exist before copy

     const QString filedest = QStandardPaths::writableLocation(QStandardPaths::GenericDataLocation) + QLatin1String("/data/app/") + "mydatabase.db";
if (!QFile::exists(filedest)) {
   // you can use  QVERIFY(QFile::copy(src, filedest)); 
   QFile::copy(src, filedest)
   }

Updated answer: Created a simple project

   QT += core gui
   QT += sql
   QT += webkitwidgets
   greaterThan(QT_MAJOR_VERSION, 4): QT += widgets
   TARGET = aawa
   TEMPLATE = app
   SOURCES += main.cpp
   DISTFILES += \
      ../Desktop/before/MAINQ.db

where MAINQ.db is my sqlite file. And main.cpp

   #include <QApplication>
   #include <qgraphicsscene.h>
   #include <QGraphicsView>
   #include <QVBoxLayout>
   #include <QPushButton>
   #include <QStandardPaths>
   #include <QFile>
   #include <QtSql>
   #include <QFileInfo>

   int main(int argc, char* argv[]){
   QApplication app(argc, argv);
   QGraphicsScene* scene = new QGraphicsScene;
   QGraphicsView* view = new QGraphicsView(scene);
   //scene->setBackgroundBrush((Qt::white);

   QWidget *widget = new QWidget;
    view->setBackgroundBrush(Qt::yellow);
    QVBoxLayout* vlayout = new QVBoxLayout(widget);

    vlayout->addWidget(view);
    vlayout->addWidget(new QPushButton("print"));
    printf("ok..");
    QSqlDatabase db;
    db =  QSqlDatabase::addDatabase("QSQLITE");
   //now full path of my db
    db.setDatabaseName("/Users/Ioan/Desktop/before/MAINQ.db");
    if (db.open()) {
   qDebug() << "tabele in db " << db.tables();
   QSqlQuery query(db);
       query.prepare( "SELECT id FROM user_cards");
      if( !query.exec() )
        qDebug() << query.lastError();
      else
      {
        qDebug( "Selected!" );
        QSqlRecord rec = query.record();
         int cols = rec.count();
          for( int c=0; c<cols; c++ )
          qDebug() << QString( "Column %1: %2" ).arg( c ).arg( rec.fieldName(c) );

        for( int r=0; query.next(); r++ )
          for( int c=0; c<cols; c++ )
            qDebug() << QString( "Row %1, %2: %3" ).arg( r ).arg( rec.fieldName(c) ).arg( query.value(c).toString() );
      }
      qDebug() << "nice.";
   }


    else {
         qDebug() << "DB not open.";
         }

          const QString src = "/Users/Ioan/Desktop/before/MAINQ.db";      
   db.close(); // for close connection
   const QString filedest = QStandardPaths::writableLocation(QStandardPaths::GenericDataLocation) + QLatin1String("/data/app/") + "mydatabase.db";
   QFile file( filedest );
    if( !file.exists() )
    {
      qDebug() << "The file" << file.fileName() << "does not exist.";
    //  return 0;
    } else {

          QFile::copy(file, filedest);
    }


 widget->show();
return app.exec();
 }

There we have connected to our db and execute some query. We verify if file exists, if not we copy it to some location. The result from sql we can assign to variables, then use them as String in WebView etc.