This provides rough steps to follow when porting an application using Qt WebKit's QWebView API to use Qt WebEngine's QWebEngineView.

Class Names

The Qt WebEngine equivalent of Qt WebKit C++ classes are prefixed by "QWebEngine" instead of "QWeb".

Qt WebKit

#include <QWebHistory>
#include <QWebHistoryItem>
#include <QWebPage>
#include <QWebView>

QWebHistory
QWebHistoryItem
QWebPage
QWebView

Qt WebEngine

#include <QWebEngineHistory>
#include <QWebEngineHistoryItem>
#include <QWebEnginePage>
#include <QWebEngineView>

QWebEngineHistory
QWebEngineHistoryItem
QWebEnginePage
QWebEngineView

Qt Module Name

In qmake Project Files

Qt WebKit

QT += webkitwidgets

Qt WebEngine

QT += webenginewidgets

Including the Module in Source Files

Qt WebKit

#include <QtWebKit/QtWebKit>
#include <QtWebKitWidgets/QtWebKitWidgets> // With Qt >= 4.8

Qt WebEngine

#include <QtWebEngineWidgets/QtWebEngineWidgets>

QWebFrame has been Merged into QWebEnginePage

It is not possible to access sub-frames. Methods of the main QWebFrame are now available directly through the QWebEnginePage itself.

Qt WebKit

QWebPage page;
connect(page.mainFrame(), SIGNAL(urlChanged(const QUrl&)), SLOT(mySlotName()));
page.mainFrame()->load(url);

Qt WebEngine

QWebEnginePage page;
connect(&page, SIGNAL(urlChanged(const QUrl&)), SLOT(mySlotName()));
page.load(url);

Some methods now return their result asynchronously

Since Qt WebEngine uses a multi-process architecture, applications needs to return to the event loop where the result will be received asynchronously from Qt WebEngine's render process. A function pointer, a functor or a lambda expression must be provided to handle the result when it is available.

Qt WebKit

QWebPage *page = new QWebPage;
QTextEdit *textEdit = new QTextEdit;
// *textEdit is modified immediately.
textEdit->setPlainText(page->toHtml());
textEdit->setPlainText(page->toPlainText());

Qt WebEngine (with a lambda function in C++11)

QWebEnginePage *page = new QWebEnginePage;
QTextEdit *textEdit = new QTextEdit;
// *textEdit must remain valid until the lambda function is called.
page->toHtml([textEdit](const QString &result){ textEdit->setPlainText(result); });
page->toPlainText([textEdit](const QString &result){ textEdit->setPlainText(result); });

Qt WebEngine (with a functor template wrapping a member function)

template<typename Arg, typename R, typename C>
struct InvokeWrapper {
    R *receiver;
    void (C::*memberFun)(Arg);
    void operator()(Arg result) {
        (receiver->*memberFun)(result);
    }
};

template<typename Arg, typename R, typename C>
InvokeWrapper<Arg, R, C> invoke(R *receiver, void (C::*memberFun)(Arg))
{
    InvokeWrapper<Arg, R, C> wrapper = {receiver, memberFun};
    return wrapper;
}

QWebEnginePage *page = new QWebEnginePage;
QTextEdit *textEdit = new QTextEdit;
// *textEdit must remain valid until the functor is called.
page->toHtml(invoke(textEdit, &QTextEdit::setPlainText));
page->toPlainText(invoke(textEdit, &QTextEdit::setPlainText));

Qt WebEngine (with a regular functor)

struct SetPlainTextFunctor {
    QTextEdit *textEdit;
    SetPlainTextFunctor(QTextEdit *textEdit) : textEdit(textEdit) { }
    void operator()(const QString &result) {
        textEdit->setPlainText(result);
    }
};

QWebEnginePage *page = new QWebEnginePage;
QTextEdit *textEdit = new QTextEdit;
// *textEdit must remain valid until the functor is called.
page->toHtml(SetPlainTextFunctor(textEdit));
page->toPlainText(SetPlainTextFunctor(textEdit));

Qt WebEngine does not Interact with QNetworkAccessManager

Some classes of Qt Network such as QAuthenticator were reused for their interface but, unlike Qt WebKit, Qt WebEngine has its own HTTP implementation and can't go through a QNetworkAccessManager.

Signals and methods of QNetworkAccessManager that are still supported were moved to QWebEnginePage directly.

Qt WebKit

QNetworkAccessManager qnam;
QWebPage page;
page.setNetworkAccessManager(&qnam);
connect(&qnam, SIGNAL(authenticationRequired(QNetworkReply*,QAuthenticator*)), this, SLOT(authenticate(QNetworkReply*,QAuthenticator*)));

Qt WebEngine

QWebEnginePage page;
connect(&page, SIGNAL(authenticationRequired(QNetworkReply*,QAuthenticator*)), this, SLOT(authenticate(QNetworkReply*,QAuthenticator*)));

Notes about Individual Methods

evaluateJavaScript

QWebFrame::evaluateJavaScript was renamed and moved as QWebEnginePage::runJavaScript. It is currently only possible to run JavaScript on the main frame of a page and the result is returned asynchronously to the provided functor.

Qt WebKit

QWebPage *page = new QWebPage;
qDebug() << page->mainFrame()->evaluateJavaScript("'Java' + 'Script'");

Qt WebEngine (with lambda expressions in C++11)

QWebEnginePage *page = new QWebEnginePage;
page->runJavaScript("'Java' + 'Script'", [](const QVariant &result){ qDebug() << result; });

setHtml and setContent

QWebEnginePage::setHtml and QWebEnginePage::setContent perform asynchronously the same way as a normal HTTP load would, unlike their QWebPage counterparts.

setContentEditable

QWebPage::setContentEditable has no equivalent since any document element can be made editable through the contentEditable attribute in the latest HTML standard. Therefore, QWebEnginePage::runJavaScript is all that is needed.

Qt WebKit

QWebPage page;
page.setContentEditable(true);

Qt WebEngine

QWebEnginePage page;
page.runJavascript("document.documentElement.contentEditable = true");

Unavailable Qt WebKit APIs

Qt WebKit classes and methods in this list will not be available in Qt WebEngine.