Qt: Open links with target in default browser, without leaking memory

c++, memory-leaks, qt, qwebview

Solution

It seems the view becomes useless after the page is rendered in the extern browser. You might just schedule the ExternalWebView for deletetion with deleteLater():

#include <iostream>

#include <QApplication>
#include <QGridLayout>
#include <QNetworkRequest>
#include <QDesktopServices>

#include <QEvent>
#include <QMainWindow>
#include <QWebView>

class ExternWebPage : public QWebPage {
    //Q_OBJECT

    public:
    ExternWebPage(QObject* parent = 0)
    :   QWebPage(parent)
    {
        std::cout << "ExternWebPage" << std::endl;
    }

    ~ExternWebPage() {
        std::cout << "Destroy ExternWebPage" << std::endl;
    }

    virtual bool event(QEvent *e) {
        static unsigned counter;
        std::cout << ++counter << " ExternWebPage: " << e->type() << std::endl;
        return QWebPage::event(e);
    }

    bool acceptNavigationRequest(QWebFrame *, const QNetworkRequest &request, NavigationType) {
        QDesktopServices::openUrl(request.url());
        return false;
    }
};


class ExternWebView : public QWebView {
    //Q_OBJECT

    public:
    ExternWebView(QWidget* parent = 0)
    :   QWebView(parent)
    {
        std::cout << "ExternWebView" << std::endl;
    }
    ~ExternWebView() { std::cout << "Destroy ExternWebView" << std::endl; }
    virtual bool event(QEvent *e) {
        static unsigned counter;
        std::cout << ++counter << " ExternWebView: " << e->type() << std::endl;
        return QWebView::event(e);
    }
};


class InternalWebView : public QWebView {
    //Q_OBJECT

    public:
    InternalWebView(QWidget* parent = 0)
    :   QWebView(parent)
    {}
    QWebView* createWindow(QWebPage::WebWindowType) {
        auto res = new ExternWebView();
        res->setPage(new ExternWebPage(res));
        res->deleteLater();
        return res;
    }
};


class Window : public QMainWindow {
    //Q_OBJECT

    public:
    Window()
    :   QMainWindow()
    {
        std::cout << "Window" << std::endl;
        auto web = new InternalWebView(this);
        web->setHtml("<div align=\"center\"><a href=\"http://www.google.com/\">Same Window</a> <a href=\"http://www.google.com/\" target=\"_blank\">New Window</a></div>");
        setCentralWidget(web);
    }
    ~Window() { std::cout << "Destroy Window" << std::endl; }

};


int main(int argc, char *argv[]) {
  QApplication a(argc, argv);
  Window w;
  w.show();
  return a.exec();
}

Test without deletion:

Window
ExternWebView
1 ExternWebView: 68
ExternWebPage
2 ExternWebView: 74
3 ExternWebView: 75
1 ExternWebPage: 43
2 ExternWebPage: 43
3 ExternWebPage: 43
4 ExternWebPage: 43
5 ExternWebPage: 43
Destroy Window

Test with delete later:

ExternWebView
1 ExternWebView: 68
ExternWebPage
2 ExternWebView: 74
3 ExternWebView: 75
4 ExternWebView: 52
Destroy ExternWebView
Destroy ExternWebPage
Destroy Window

Problem

Searching through the Internet, I've come across so many ways, mostly nonfunctional, nonspecific, or partially functional, to do various things with `QWebView` and opening URLs. After much swearing and cursing, I've managed to get an example to do what I want, which is open normal links normally, and open anything that requests a new window in the external browser; however, there's a hitch. It leaks memory, because I make a bunch of extra `WebViews` that aren't cleaned up until the process exits. How can I do this without leaking memory? Please forgive my rather sophomoric understanding of Qt in advance. I've only been using it for a handful of hours at this point. SSCCE: test.hpp ``` #include <QMainWindow> #include <QWebView> class Window : public QMainWindow { Q_OBJECT public: Window(); private: QWebView* m_web; private slots: }; class WebPage : public QWebPage { Q_OBJECT public: bool acceptNavigationRequest(QWebFrame *frame, const QNetworkRequest &request, NavigationType type); }; class WebView : public QWebView { Q_OBJECT public: QWebView* createWindow(QWebPage::WebWindowType type); }; ``` test.cpp ``` #include <QApplication> #include <QGridLayout> #include <QNetworkRequest> #include <QDesktopServices> #include "test.hpp" Window::Window() : QMainWindow() { m_web = new WebView; m_web->setHtml("<div align=\"center\"><a href=\"http://www.google.com/\">Same Window</a> <a href=\"http://www.google.com/\" target=\"_blank\">New Window</a></div>"); setCentralWidget(m_web); } bool WebPage::acceptNavigationRequest(QWebFrame*, QNetworkRequest const& request, NavigationType) { QDesktopServices::openUrl(request.url()); return false; } QWebView* WebView::createWindow(QWebPage::WebWindowType) { auto res = new WebView; auto page = new WebPage; res->setPage(page); return res; } int main(int argc, char *argv[]) { QApplication a(argc, argv); Window w; w.show(); return a.exec(); } ``` test.pro ``` QT += core gui network webkitwidgets widgets TEMPLATE = app TARGET = test INCLUDEPATH += . CONFIG += c++11 # Input SOURCES += test.cpp HEADERS += test.hpp ``` To Compile and Run ``` qmake test.pro make ./test ```

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