int main(int argc, char *argv[]){
    std::map<int,int> keyMap;
    keyMap[1] = Qt::Key_Escape;
    //...
    auto keyHandler = [&](int keyCode){
        QKeyEvent *event = new QKeyEvent ( QEvent::KeyPress, keyMap[keyCode], Qt::NoModifier);
        QCoreApplication::sendEvent(app, event);
    };
    QObject::connect(apiExternalLink, &ApiExternalLink::keyPressed, app, keyHandler, Qt::QueuedConnection);
}