QWebPage, getting the mime type

Question

I am wondering how I can get the mime-type of the current page using a QWebPage. Also, if possible, I would like to be able to do this using the HEAD request so I know not to download the whole page if it's not the correct mime-type. Any ideas?

Answer 1

It is possible. You will want to use QNetworkAccessManager, QNetworkRequest, and QNetworkReply classes.

Here's an (untested) example, but should get you started with retrieving the mime-type of a page using a HEAD request:

class TestClass: public QObject
{
    Q_OBJECT
public:
    TestClass();
    void run();

public slots:
    void ready(QNetworkReply * response);

protected:
    QNetworkAccessManager * manager;
};


TestClass::TestClass()
{
    manager = new QNetworkAccessManager(this);

    this->connect(manager, SIGNAL(finished(QNetworkReply*)), this, SLOT(ready(QNetworkReply*)));
}

void TestClass::run()
{
    QUrl url("http://www.widefido.com/");

    manager->head(QNetworkRequest(url));
}

void TestClass::ready(QNetworkReply * response)
{
    QVariant contentMimeType = response->header(QNetworkRequest::ContentTypeHeader);

    qDebug() << contentMimeType;
}

NOTE: If the server does not send back a ContentType header, your QVariant will be invalid. So, before using contentMimeType, make sure you check if it is valid first. Then you can convert to a QString for checking against your list of valid mime-types.

NOTE: QNetworkRequests are asynchronous, so you'll have to implement a signal-slot relationship for getting the value out of the QNetworkReploy. You can also have a look in QxtSignalWaiter for doing it inline.