TXMLFile empty?

ROOT
1

Hello,

I have been using TXMLFile to read a test.xml file lately.
It turns out that the TXMLFile is empty. Am I missing something ?

TXMLFile *ff = new TXMLFile("./test.xml");
std::cout << ff->GetSize() << std::endl;

Here are some test files.

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE note SYSTEM "Note.dtd">
<note>
<to>Tove</to>
<from>Jani</from>
<heading>Reminder</heading>
<body>Don't forget me this weekend!</body>
</note>

<?xml version="1.0"?>
<main>
  <child1>Content of child1 node</child1>
  <child2 attr1="value1" attr2="value2"/>
  <child3>
    <subchild1>subchild1 content</subchild1>
    <subchild2>subchild2 content</subchild2>
    <subchild3>subchild3 content</subchild3>
  </child3>
  <child4 xmlns:child4="http://website/webpage">
    <child4:subchild1>subchild1 content</child4:subchild1>
    <child4:subchild2>subchild2 content</child4:subchild2>
    <child4:subchild3>subchild3 content</child4:subchild3>
  </child4>
</main>
2

Hi,

TXMLFile class has its own layout and designed to store objects - like histograms or graphs.

If you want to parse arbitrary XML file, you have to use generic XML parser.
See tutorials with simple XML parser:

xmlnewfile.C
xmlreadfile.C

Or more complex one with libxml2:

DOMParsePerson.C

All XML-related tutorials are:

https://root.cern/doc/master/group__tutorial__xml.html

Regards,
Sergey

3

Hi, I see.

Simple XML parser tutorial didn’t seems to work neither. Is that expected ?

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE note SYSTEM "Note.dtd">
<note>
<to>Tove</to>
<from>Jani</from>
<heading>Reminder</heading>
<body>Don't forget me this weekend!</body>
</note>

I would be happy to follow TXMLFile layout.
Is there any TXMLFile tutorial too ?

4

It can be used as normal ROOT file:

auto obj = new TNamed("name", "title");
auto f = TFile::Open("file.xml", "recreate");
obj->Write("t1");
delete f;

And then:

auto f1 = TFile::Open("file.xml");
auto obj1 = f1->Get("t1");
obj1->Print();

I would not recommend trying to reproduce layout of this XML file - it has several special components like streamer infos or directory organization.

Just use functionality of TFile class. See documentation:

https://root.cern/doc/master/classTFile.html

5

Thanks for the explanation! Sounds clear now

Actually none of the xml files with a DTD are not loading with TXMLEngine.
I actually need to have this line in these files

Do you have a suggestion how to fix it ?

6

TXMLEngine is simple but fast parser, which does not support DTD.
You should try to use TDOMParser class.

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7

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