How to use QWebEngineUrlRequestInterceptor

Question

I need to intercept requests made in our WebEngine qml component in our Qt application.

I have found documentation on QWebEngineUrlRequestInterceptor which seems to do just this here http://doc.qt.io/qt-5/qwebengineprofile.html#details and here http://doc.qt.io/qt-5/qwebengineurlrequestinterceptor.html#details. However I haven't found any code examples on how to do this in Qt/C++.

Any help is appreciated.

Answer 1

Managed to puzzle it together with the help of this post: https://forum.qt.io/topic/69135/how-to-send-network-requests-in-qwebengine/2

This is my solution to hook up a QWebEngineUrlRequestInterceptor:

.h file

class WebUrlRequestInterceptor : public QWebEngineUrlRequestInterceptor
{
    Q_OBJECT

public:
    WebUrlRequestInterceptor(QObject *p = Q_NULLPTR);
    void interceptRequest(QWebEngineUrlRequestInfo &info);
};

.cpp file

WebUrlRequestInterceptor::WebUrlRequestInterceptor(QObject *p)
  :QWebEngineUrlRequestInterceptor(p)
{

}
void WebUrlRequestInterceptor::interceptRequest(QWebEngineUrlRequestInfo &info) {
    QString rsrct = "";
    switch(info.resourceType()){
        case 0:rsrct="ResourceTypeMainFrame = 0, // top level page";break;
        case 1:rsrct="ResourceTypeSubFrame, // frame or iframe";break;
        case 2:rsrct="ResourceTypeStylesheet, // a CSS stylesheet";break;
        case 3:rsrct="ResourceTypeScript, // an external script";break;
        case 4:rsrct="ResourceTypeImage, // an image (jpg/gif/png/etc)";break;
        case 5:rsrct="ResourceTypeFontResource, // a font";break;
        case 6:rsrct="ResourceTypeSubResource, // an other subresource.";break;
        case 7:rsrct="ResourceTypeObject, // an object (or embed) tag for a plugin,";break;
        case 8:rsrct="ResourceTypeMedia, // a media resource.";break;
        case 9:rsrct="ResourceTypeWorker, // the main resource of a dedicated worker.";break;
        case 10:rsrct="ResourceTypeSharedWorker, // the main resource of a shared worker.";break;
        case 11:rsrct="ResourceTypePrefetch, // an explicitly requested prefetch";break;
        case 12:rsrct="ResourceTypeFavicon, // a favicon";break;
        case 13:rsrct="ResourceTypeXhr, // a XMLHttpRequest";break;
        case 14:rsrct="ResourceTypePing, // a ping request for <a ping>";break;
        case 15:rsrct="ResourceTypeServiceWorker, // the main resource of a service worker.";break;
        case 16:rsrct="ResourceTypeUnknown";break;

        default : rsrct="Unknown type";break;
    }

  qDebug()<<"\t"<<Q_FUNC_INFO<<":\n\t\t" << "WebUrlRequestInterceptor::interceptRequest    " <<info.requestMethod()
         <<"\r\n  "<<info.requestUrl()<<"   "<<rsrct      <<"\r\n";

}

main.cpp file

WebUrlRequestInterceptor *wuri = new WebUrlRequestInterceptor();
QWebEngineProfile::defaultProfile()->setRequestInterceptor(wuri);

Answer 2

The QWebEngineUrlRequestInterceptor class provides an abstract base class for URL interception, i recommend it to handle custom protocols, (mail://, example:// ....)

Let's implement it by subclasing QWebEngineUrlRequestInterceptor:

Your header file exampleurlschemehandler.h file:

class ExampleUrlSchemeHandler : public QWebEngineUrlSchemeHandler
{
    Q_OBJECT
public:
    explicit ExampleUrlSchemeHandler(QObject *parent = 0);
public:

    void requestStarted(QWebEngineUrlRequestJob *request);
};

Your cpp file:

ExampleUrlSchemeHandler::ExampleUrlSchemeHandler(QObject *parent) : QWebEngineUrlSchemeHandler(parent){}

void ExampleUrlSchemeHandler::requestStarted(QWebEngineUrlRequestJob *request){
    // Abort the request if you want to redirect it or something
    request->fail(QWebEngineUrlRequestJob::RequestAborted);
    // Get the URL
    const QUrl url = request->requestUrl();
    // Do amazing thing with your URL
    // .....
}

Now install it in your default QWebEngineProfile:

const QString EXAMPLE_SCHEMA_HANDLER = "example://" /* http://, https://, mail:// ....   */;
const QWebEngineUrlSchemeHandler* installed =  QWebEngineProfile::defaultProfile()->urlSchemeHandler(EXAMPLE_SCHEMA_HANDLER);
        if (!installed)
            profile()->installUrlSchemeHandler(EXAMPLE_SCHEMA_HANDLER, new WebAppUrlSchemeHandler(this));

Other method, to handle HTTP/HTTPS request is subclassing QWebEnginePage, and reimplementing acceptNavigationRequest():

bool WebAppPage::acceptNavigationRequest(const QUrl &url, QWebEnginePage::NavigationType type, bool main) {
    // Example: We want to redirect all links clicked by user to native webbrowser
        if (type == QWebEnginePage::NavigationTypeLinkClicked)
                QDesktopServices::openUrl(url);
}

Now, set this page in your QWebEngineView.