Insert node in the xml file directly

[mitien]

Is there any way to insert nodes directly in xml file without recreating full xml document with builder?

<rootNode>
...
  <mainNode>
...
    <randomNode>111</randomNode>
    <randomNode2>1</randomNode2>
    <randomNode3><subNode1><dataId>1</dataId></subNode1></randomNode3>
    <item name="Text1"><dataValue>1</dataValue></item >
    <item name="Text2"><dataValue>2</dataValue></item >
    <item name="Text3"><dataValue>3</dataValue></item >

    >>>>>> insert here ( example <item name="Text4"><dataValue>4</dataValue></item > ) <<<<<<

    <subNode2><child>text text</child></subNode2>
...
  <mainNode>
...
</rootNode>

[renggli]

Sure, something along those lines should work:

final document = XmlDocument.parse(input);
final mainNode = document.findAllElements('mainNode').first;
final lastItemNode = mainNode.findAllElements('item').last;
final lastItemIndex = mainNode.children.indexOf(lastItemNode);
final builder = XmlBuilder();
builder.element('item',
     attributes: {'name': 'Text4'},
     nest: () => builder.element('dataValue', nest: 4));
mainNode.children.insert(lastItemIndex + 1, builder.buildFragment());
final output = document.toXmlString();

[mitien]

Thanks a lot is helps.

One more question if you don`t mind.

Both builder.buildFragment() and builder.buildDocument() are one-timers. Right?

//print children
print(builder.buildFragment().children);  
//print []
print(builder.buildFragment().children);  

[renggli]

Correct, see builder.dart#L252.

If you want multiple instances you can copy the built tree:

final item = builder.buildFragment();
final copy = item.copy();

[mitien]

Ok. Got it.

But new question appear. Please correct me if I`m wrong.

If use event driven API strategy will be the same?

1. find out index of element
2. find that item in the main tree
3. update/remove/insert new.

if need to do the same with multiple nodes - rinse and repeat.

Thanks in advance

[renggli]

With the event driven API the solution will be very different: you need to identify the place when to insert/transform/modify something, perform this transformation by editing the generated events, and then serializing it back to a string.

[mitien]

Thanks. Understood.