class NetworkAccessManager : public QNetworkAccessManager
{
    Q_OBJECT
public:
    NetworkAccessManager(QObject *parent) : QNetworkAccessManager(parent) {}

private:
    QHash <QString,QNetworkReply> handlers;

protected:
    QNetworkReply *createRequest(
        Operation op, const QNetworkRequest &request, QIODevice *outgoingData)
    {
        QNetworkReply *reply;
        QString scheme = request.url().scheme();

        if (handlers.contains(scheme)) {
            // get reply...
        } else {
            reply = QNetworkAccessManager::createRequest(op, request, outgoingData);
        }

        return reply;
    }

    void addSchemeHandler(QString scheme, QNetworkReply *class) {
        handlers[scheme] = class;
    }
}

class MainWindow : public QMainWindow
{
    Q_OBJECT
public:
    MainWindow(QObject *parent) : QMainWindow(parent) {
        n_nam.addSchemeHandler("home", DirSchemeHandler("/home/speakman"));
        n_nam.addSchemeHandler("temp", DirSchemeHandler("/tmp"));
        n_nam.addSchemeHandler("config", ConfigSchemeHandler());

        QWebView *m_webview = new QWebView(this);
        m_webview->setNetworkAccessManager(m_nam);
        n_nam.addSchemeHandler("config", ConfigSchemeHandler());

        QWebView *m_webview = new QWebView(this);
        m_webview->setNetworkAccessManager(m_nam);
    }
}