parse xml

[rmagro]

is there a generic way to parse all the node of a xml document, and print out the element name its attributes (name="value") and its values ?
For generic way I mean something that not require me to loop many time based on annidation lavel, since in this case it means I have to know the xml specific annidation level..

Thank you
roby

[wysota]

You can write a recursive parser using QXmlStreamReader or QDomDocument. You can start with this:

void displayElement(const QDomElement &elem, int indent = 0){
  QString out = QString(indent, ' ')+elem.name()+" ";
  out += /* parse attributes here */
  qDebug() << out;
  for(QDomElement subElem = elem.firstChildElement(); !elem.isNull(); subElem = subElem.nextSiblingElement()){
    displayElement(subElem, indent+4);
  }
}
 
QDomDocument doc;
doc.setContent(...);
displayElement(doc.documentElement());

void displayElement(const QDomElement &elem, int indent = 0){
  QString out = QString(indent, ' ')+elem.name()+" ";
  out += /* parse attributes here */
  qDebug() << out;
  for(QDomElement subElem = elem.firstChildElement(); !elem.isNull(); subElem = subElem.nextSiblingElement()){
    displayElement(subElem, indent+4);
  }
}

QDomDocument doc;
doc.setContent(...);
displayElement(doc.documentElement());

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[smeck]

This is the QXmlStreamReader version. This example will create an output like the following:

-----start----
[ElementName]
[Attribute = Value, ...]
[ElementText if existing]
-----end-----

The bool flag is necessary since reader.readElementText() raises an error if there is no element text. The stream reader version should have very good performance.

QFile sourceFile("source.xml");
	if( !sourceFile.open( QIODevice::ReadOnly ) )
		return;
 
	QFile targetFile("output.txt");
	if( !targetFile.open( QIODevice::WriteOnly ) )
		return;
 
	QXmlStreamReader reader(&sourceFile);
 
	QTextStream writer(&targetFile);
 
 
	bool lastElementHadText = true;
	while( !reader.atEnd() ) {
 
		reader.readNext();
 
		if( reader.isStartElement() ) {
			if( !lastElementHadText )
				writer << "-----end-----" <<endl;
 
			writer << "-----start-----" << endl;
			writer << reader.name().toString() << endl;
			foreach( QXmlStreamAttribute attribute, reader.attributes() ) {
					writer << attribute.name().toString() << "=" << attribute.value().toString() << ", ";
			}
			if( reader.attributes().count() > 0 )
				writer << endl;
		}
 
		if( reader.isCharacters() && !reader.isWhitespace() ) {
			lastElementHadText = true;
			writer << reader.text().toString() << endl;
			writer << "-----end-----" <<endl;
		}
 
	}
 
	writer.flush();
	targetFile.close();
	sourceFile.close();

QFile sourceFile("source.xml");
	if( !sourceFile.open( QIODevice::ReadOnly ) )
		return;

	QFile targetFile("output.txt");
	if( !targetFile.open( QIODevice::WriteOnly ) )
		return;

	QXmlStreamReader reader(&sourceFile);

	QTextStream writer(&targetFile);


	bool lastElementHadText = true;
	while( !reader.atEnd() ) {

		reader.readNext();

		if( reader.isStartElement() ) {
			if( !lastElementHadText )
				writer << "-----end-----" <<endl;

			writer << "-----start-----" << endl;
			writer << reader.name().toString() << endl;
			foreach( QXmlStreamAttribute attribute, reader.attributes() ) {
					writer << attribute.name().toString() << "=" << attribute.value().toString() << ", ";
			}
			if( reader.attributes().count() > 0 )
				writer << endl;
		}

		if( reader.isCharacters() && !reader.isWhitespace() ) {
			lastElementHadText = true;
			writer << reader.text().toString() << endl;
			writer << "-----end-----" <<endl;
		}

	}

	writer.flush();
	targetFile.close();
	sourceFile.close();

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greetings