Question

I’m having trouble accessing the content of QNetworkReply objects. Content appears to be empty or zero. According to the docs (translating from c++ to java) I think I’ve got this set up correctly, but to no avail. Additionally an “Unknown error” is being reported.

Any ideas much appreciated. Code:

public class Test extends QObject {

    private QWebPage page;

    public Test() {

        page = new QWebPage();

        QNetworkAccessManager nac = new QNetworkAccessManager();
        nac.finished.connect(this, "requestFinished(QNetworkReply)");

        page.setNetworkAccessManager(nac);

        page.loadProgress.connect(this, "loadProgress(int)");
        page.loadFinished.connect(this, "loadFinished()");

    }

    public void requestFinished(QNetworkReply reply) {

        reply.reset();
        reply.open(OpenModeFlag.ReadOnly);

        reply.readyRead.connect(this, "ready()");  // never gets called

        System.out.println("bytes: " + reply.url().toString());  // writes out asset uri no problem
        System.out.println("bytes: " + reply.bytesToWrite());  // 0
        System.out.println("At end: " + reply.atEnd());   // true
        System.out.println("Error: " + reply.errorString());   // "Unknown error"
    }

    public void loadProgress(int progress) {
        System.out.println("Loaded " + progress + "%");
    }

    public void loadFinished() {
        System.out.println("Done");
    }

    public void ready() {
        System.out.println("Ready");
    }

    public void open(String url) {
        page.mainFrame().load(new QUrl(url));
    }

    public static void main(String[] args) {

        QApplication.initialize(new String[] { });

        Test t = new Test();
        t.open("http://news.bbc.co.uk");

        QApplication.exec();
    }

}

Answer 1

I imagine that the QWebPage has already queried all the QNetworkReply objects as they came in. The docs say

QNetworkReply is a sequential-access
QIODevice, which means that once data
is read from the object, it no longer
kept by the device. It is therefore
the application’s responsibility to
keep this data if it needs to.

so resetting it isn’t going to work.

Note that if you make the network request directly through QNetworkAccessManager you do get a QNetworkReply with data available. You only get one though for the actual URL whereas the QWebPage approach downloads everything else after that i.e. images, js, etc.