Read data of a website

[artwaw]

@Linz Hi, I don't know about the error (I personally would investigate that).
To parse XML you can use https://doc.qt.io/qt-5/qxmlstreamreader.html

[Linz]

I fixed the error, something with my proxy was off ^^

Do you have an idea how I can convert the QByteArray buffer to a char? Would It make way more easy to access the values I need.

[SGaist]

Hi,

No need to convert anything.

You can access the internal data using the QByteArray::data function.

[VRonin]

@Linz said in Read data of a website:

Do you have an idea how I can convert the QByteArray buffer to a char? Would It make way more easy to access the values I need.

Don't do this.

@artwaw said in Read data of a website:

To parse XML you can use https://doc.qt.io/qt-5/qxmlstreamreader.html

Do this!

[SGaist]

I somehow missed the XML part.

My fellows are correct, use QXmlStreamReader.

[Linz]

Sorry for bothering you: I read the documentation for QXmlStreamReader, but I still have no clue how to filter the data. Maybe I am still missing the basics too much to understand what I need...

If I refer to the picture I want to save the first value 49.986, the second value 132.3 and the third value 0 in an array(s) of type double (to plot it later on).

But which function could do this for me?
I tried something like:
void QXmlStreamReader::addData(const QByteArray &buffer);

but it doesn't work. I could filter it easily if it would have been an array of char :/

[Kent-Dorfman]

higher level:

curl
wget

[JonB]

@Linz
You just want to parse input XML. I don't think you'll particularly be needing QXmlStreamReader::addData(). You're just wanting to read elements and access values.

There is a Qt example at https://doc.qt.io/qt-5/qtxml-streambookmarks-example.html. But for you you're only interested in the XbelReader::readXBEL() part. It should get you started on how to read through an XML document.

[VRonin]

const QByteArray replyData = reply->readAll();
QXmlStreamReader xmlreader(replyData);
bool rStarted = false;
while (!xmlreader.atEnd() && !xmlreader.hasError()) {
    switch(xmlreader.readNext()){
    case QXmlStreamReader::StartElement:
        if(xmlreader.name()==QLatin1String("r"))
            rStarted = true;
        else if(rStarted && xmlreader.name()==QLatin1String("f"))
            qDebug() << "f" << xmlreader.readElementText();
        else if(rStarted && xmlreader.name()==QLatin1String("z"))
            qDebug() << "z" << xmlreader.readElementText();
        else if(rStarted && xmlreader.name()==QLatin1String("p"))
            qDebug() << "p" << xmlreader.readElementText();
        else if(rStarted && xmlreader.name()==QLatin1String("dt"))
            qDebug() << "dt" << xmlreader.readElementText();
    break;
    case QXmlStreamReader::EndElement:
        if(xmlreader.name()==QLatin1String("r"))
            rStarted = false;
    break;
    default:
    break;
    }
}

[Linz]

@VRonin Thanks a lot! Where do you define readElementText() since I get the Error:
Error: use of undeclared identifier 'readElementText'

I tried to define it as QString readElementText() in the header, but it doesn't seem to work.

[VRonin]

Sorry forgot to add xmlreader. amended now