Retrieving single value from an QXmlQuery

[hsfougaris]

If I have a QString with an XML document, is the best way to retrieve a single node the following?

@
QBuffer device;
device.setData(myQString.toUtf8());
device.open(QIODevice::ReadOnly);

QXmlQuery query;
query.setQuery("doc($inputDocument)/query[myValueOfInterest]");
query.bindVariable("inputDocument", &device);

QXmlSerializer serializer(query, myOutputDevice);
query.evaluateTo(&serializer);
@

or is there some other API more appropriate?
I'm asking because it seems very complicated for retrieving a single value (it's actually the response from a SOAP service), so I'd like to be sure.

thanks.

[hsfougaris]

Well, there must be something wrong with the above (or I am doing it wrong) because there is no joy...
Here is my exact code:
@
QBuffer device;
device.setData(resp.toUtf8());
device.open(QIODevice::ReadOnly);
QXmlQuery query;

query.setQuery("doc($inputDocument)/query[XMLActionResponse]");
query.bindVariable("inputDocument", &device);

QString * outStr = new QString();
if (query.evaluateTo(outStr)) {
    qDebug() << "OK!"
} else {
    qDebug() << "Error!";

}

@

The XML (stored in the QString resp) is this:
@
<?xml version="1.0"?>
<SOAP-ENV:Envelope xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:SOAP-ENC="http://schemas.xmlsoap.org/soap/encoding/">
<SOAP-ENV:Body SOAP-ENV:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/">
<NS1:XMLActionResponse xmlns:NS1="urn:SoapSrvURN">
<return xsi:type="xsd:string>Some return value</return>
</NS1:XMLActionResponse>
</SOAP-ENV:Body>
</SOAP-ENV:Envelope>
@

I would expect to get "Some return value", or more likely "<return xsi:type="xsd:string>Some return value</return>", but instead evaluate returns false.

What am I doing wrong?

[tobias.hunger]

Did you read the documentation of evaluateTo? That quite clearly states that the method does return a bool...

[hsfougaris]

ok, you're right. I mean of course that I would expect the evaluateTo to return true, and I would then have the said strings in the outStr variable.

So, it seems my query is wrong, but I haven't been able to get it right for my particular XML.

[hsfougaris]

My workaround since the query is such a mystery:

Isolate the response of interest in a string with a string operation, and operate on the actual response data with a QDomDocument.

@
//resp holds our response from the SOAP service
QString t1 = "<NS1:XMLActionResponse xmlns:NS1="urn:SoapSrvURN">";
QString t2 = "</NS1:XMLActionResponse>";
int pos1 = resp.indexOf(t1);
if (pos1 == -1) return;
pos1 += t1.length();
int pos2 = resp.indexOf(t2);
if (pos2 == -1) return;
QString resp2 = resp.mid( pos1, pos2 -pos1 );
//resp2 now has only the 'answer' from the SOAP service

QDomDocument domDoc;
domDoc.setContent(resp2);
QDomElement n = domDoc.firstChildElement();
QDomNode _n = n.firstChild();
qDebug() << _n.nodeValue();
qDebug() << _n.firstChildElement().nodeName();
...
@