CODEWITHSUNDEEP
xmlqtxpathxquery
user322610
user322610

Reputation:

How do I use QXmlQuery properly? (Qt XQuery/XPath)

I'm using the following code to load in an XML file (actually an NZB):

QXmlQuery query;
query.bindVariable("path", QVariant(path));

query.setQuery("doc($path)/nzb/file/segments/segment/string()");
if(!query.isValid())
    throw QString("Invalid query.");

QStringList segments;
if(!query.evaluateTo(&segments))
    throw QString("Unable to evaluate...");

QString string;
foreach(string, segments)
    qDebug() << "String: " << string;

With the following input, it works as expected:

<?xml version="1.0" encoding="iso-8859-1" ?>
<!DOCTYPE nzb PUBLIC "-//newzBin//DTD NZB 1.0//EN" "http://www.newzbin.com/DTD/nzb/nzb-1.0.dtd">
<nzb>
    <file>
        <groups>
            <group>alt.binaries.cd.image</group>
        </groups>
        <segments>
            <segment>[email protected]</segment>
        </segments>
    </file>
</nzb>

However, with the following input no results are returned. This is how the input should be formatted, with attributes:

<?xml version="1.0" encoding="iso-8859-1" ?>
<!DOCTYPE nzb PUBLIC "-//newzBin//DTD NZB 1.0//EN" "http://www.newzbin.com/DTD/nzb/nzb-1.0.dtd">
<nzb xmlns="http://www.newzbin.com/DTD/2003/nzb">
    <file poster="[email protected]" date="1225385180" subject="ubuntu-8.10-desktop-i386 - ubuntu-8.10-desktop-i386.par2 (1/1)">
        <groups>
            <group>alt.binaries.cd.image</group>
        </groups>
        <segments>
            <segment bytes="66196" number="1">[email protected]</segment>
            <segment bytes="661967" number="1">[email protected]</segment>
        </segments>
    </file>
</nzb>

Please can someone tell me what I'm doing wrong?

Upvotes: 5

Views: 5817

Answers (2)

Raul Puchades
Raul Puchades

Reputation: 11

Maybe use the namespace wildcard in the query?

doc($path)//*:file/*:segments/*:segment/string()

Upvotes: 1

user322610
user322610

Reputation:

I discovered it's because I needed to supply a default namespace, that took hours to figure out...

The query is now:

declare default element namespace "http://www.newzbin.com/DTD/2003/nzb";
declare variable $path external;
doc($path)/nzb/file/segments/segment/string()

Upvotes: 8

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