QDomDocument toString conversion issue

Lolo67

In the following example

QDomDocument dom;
QDomElement element= dom.createElement("MyElement");
element.setAttribute("attr1", "foo");
element.setAttribute("attr2", "bar");
element.setAttribute("attr3", "<<statistics>> Integer status");
dom.appendChild(element);

QString text = dom.toString();
qDebug() << QString("text = %1").arg(text);

QFile outFile("C:/temp/testFile.dcf");
if ( outFile.open(QIODevice::WriteOnly|QIODevice::Text))
{
  QTextStream stream( &outFile );
  stream << text << endl;
  outFile.close();
}

The produced file will contain:

<MyElement attr2="bar" attr1="foo" attr3="&lt;&lt;statistics>> Integer status"/>

While I am awaiting it to contain:

<MyElement attr2="bar" attr1="foo" attr3="<<statistics>> Integer status"/>

Does anyone know how this could be addressed?

mrjj

Hi
Some characters must be escaped in XML documents

"   &quot;
'   &apos;
<   &lt;
>   &gt;
&   &amp;

https://stackoverflow.com/questions/1091945/what-characters-do-i-need-to-escape-in-xml-documents

It should turn into correct string once read back.

maybe

element.setAttribute("attr3", "\<\<statistics\>\> Integer status");

will work but I didnt test it.

Lolo67

Thanks for the reply.

Well I could understand that some characters must be escaped, but I do not understand the logic behind Qt escaping some of them but not all.

In my example I am passing the string: <<statistics>> Integer status
Qt is escaping the '<' characters but not the '>' characters composing the string.

Also your suggestion to write:

element.setAttribute("attr3", "\<\<statistics\>\> Integer status");

will not work for me. The code I gave here was just an example to show what I was observing. I am actually reading several XML files and use the content found in these files and combine those to create some new XML files. The "<<statistics>> Integer status" string is something I do find in the input XML files, and I would like to have this string appearing again in the XML files I am generating with my application.

mrjj

@Lolo67
Well maybe you can use

QString plain = "#include <QtCore>"
QString html = plain.toHtmlEscaped();

// html == "#include &lt;QtCore&gt;"

it seems to be a known issue with QDomDocument that not all are automatically escaped but i didnt not find further info on why.

Lolo67

Is there a way to force the characters NOT to be escaped ?

mrjj

@Lolo67
Not that I have seen.
Also that would be invalid XML.

gigglesun

Did you solved the problem, I met the same issue also.

Christian Ehrlicher

@gigglesun said in QDomDocument toString conversion issue:

I met the same issue also.

Which problem? QtXml will not create invalid xml.

mrjj

@gigglesun
Hi
Can you explain why you want to generate invalid xml ?
Some characters must be escaped or it cant be parsed.

gigglesun

@Christian-Ehrlicher @mrjj , My problem is the same with @Lolo67 in his topic, to make it more clear, I change the example as below:

    QDomDocument dom;
    QString text ="<MyElement> a &gt; b and c &lt; d</MyElement>";
    dom.setContent(text);

    QString verifyText = dom.toString();
    qDebug() << verifyText; // "<MyElement> a > b and c &lt; d</MyElement>"

My problem is why the text set to the QDomDocument is different with what we get from it.
Also, it's strange that Qt is replacing the '&gt' characters to '>' but not the '&lt' characters to '<', in fact, I do not want these change happen.
My QT version is 4.8.7, not sure if this is related with QT version.

update:
Found it's a known issue reported in https://bugreports.qt.io/browse/QTBUG-14690, till now, it's not fixed.