Can't get QXmlQuery to return results

**bpetty** · 13th May 2008, 07:51

Basically I have wrote a method to test XQuery in Qt 4.4.
I can not get this thing to return any results!
I dummied up some data in the variable "sSampleData" for testing.

I've tried different XQueries like "doc($internalFile)/html/body/p", but they all return no results. I don't get any errors... just no results.

Do you guys see something glaringly wrong?

Qt Code:

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void QtDemo44::SearchFromString(const QString& sQuery, const QString& sData)
{
	QString sSampleData = "<html>"
		"	<body>"
		"		<p id='test'>I love Jessica</p>"
		"		<p>Something else</p>"
		"	</body>"
		"</html>";
 
	QBuffer InputDevice;
    InputDevice.setData(sSampleData.toUtf8());
    bool bOpenInput = InputDevice.open(QIODevice::ReadOnly);
 
    if (bOpenInput == false)
    {
    	QMessageBox::warning(this, "Buffer Error", "Could not open buffer");
    	return;
    }
 
	QXmlQuery xmlQuery;
 
	QString sNewQuery = "declare variable $internalFile external;\n" + sQuery;
	xmlQuery.bindVariable("internalFile", &InputDevice);
	xmlQuery.setQuery(sNewQuery);
 
	bool bIsValid = xmlQuery.isValid();
 
	if (bIsValid == true)
	{
		// One way
		//QStringList slResults;
		//xmlQuery.evaluateTo(&slResults);
 
		//if (slResults.size() > 0)
		//{
		//	QMessageBox::warning(this, "Found something!", "This actually works?");
		//}
 
		// Another way
		QString sResults;
		QBuffer OutputDevice;
		OutputDevice.setData(sResults.toUtf8());
		OutputDevice.open(QIODevice::ReadWrite);
		QXmlSerializer xmlSerializer(xmlQuery, &OutputDevice);
		xmlQuery.evaluateTo(&xmlSerializer);
 
		uiDemo.txtResults->setPlainText(sResults);
	}
	else
	{
		QMessageBox::warning(this, "XQuery Error", "The query set was not valid");
	}
}

void QtDemo44::SearchFromString(const QString& sQuery, const QString& sData)
{
	QString sSampleData = "<html>"
		"	<body>"
		"		<p id='test'>I love Jessica</p>"
		"		<p>Something else</p>"
		"	</body>"
		"</html>";
	
	QBuffer InputDevice;
    InputDevice.setData(sSampleData.toUtf8());
    bool bOpenInput = InputDevice.open(QIODevice::ReadOnly);
    
    if (bOpenInput == false)
    {
    	QMessageBox::warning(this, "Buffer Error", "Could not open buffer");
    	return;
    }

	QXmlQuery xmlQuery;

	QString sNewQuery = "declare variable $internalFile external;\n" + sQuery;
	xmlQuery.bindVariable("internalFile", &InputDevice);
	xmlQuery.setQuery(sNewQuery);
	
	bool bIsValid = xmlQuery.isValid();

	if (bIsValid == true)
	{
		// One way
		//QStringList slResults;
		//xmlQuery.evaluateTo(&slResults);
		
		//if (slResults.size() > 0)
		//{
		//	QMessageBox::warning(this, "Found something!", "This actually works?");
		//}

		// Another way
		QString sResults;
		QBuffer OutputDevice;
		OutputDevice.setData(sResults.toUtf8());
		OutputDevice.open(QIODevice::ReadWrite);
		QXmlSerializer xmlSerializer(xmlQuery, &OutputDevice);
		xmlQuery.evaluateTo(&xmlSerializer);
		
		uiDemo.txtResults->setPlainText(sResults);
	}
	else
	{
		QMessageBox::warning(this, "XQuery Error", "The query set was not valid");
	}
}

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**patrik08** · 13th May 2008, 08:44

Have a look on example
/4.4.0_src/examples/xmlpatterns/recipes

QXmlFormatter return only text ??? not Domelement or node...

QXmlQuery can bee usefull only if can return and find nodes ...

**bpetty** · 13th May 2008, 14:27

Thanks patrik08. It switched to the QXmlFormatter like in the example... still didn't work. Then I change from putting a QString my QBuffer to a QByteArray... and that worked. I would really think it would work with a QString... but oh well.

Thanks a lot!