操纵用PHP的XML文件和DOM

Question

我有如下的XML文件：

<?xml version="1.0" encoding="UTF-8"?> 
<root version="8.0.0.0"> 
<songs name="Album"> 
    <row> 
    <song artist="artist_name">Track1</song> 
    </row> 
    <row> 
    <song artist="artist_name">Track2</song> 
    </row> 
    <row> 
    <song artist="artist_name">Track3</song> 
    </row> 
    <row> 
    <song artist="artist_name">Track4</song> 
    </row> 
</songs> 
</root> 

现在我想多带些行更新此文件。我如何将数据追加到现有行元素的顶部？同时添加新的元素，我想检查曲目 - Track1，Track2不重复。

我目前正在操纵该XML文件用PHP：DOM，但其在现有行的底部附加数据。用来做上面的东西

PHP代码

<?php 
//Creates XML string and XML document using the DOM 
$dom = new DOMDocument(); 
$dom->formatOutput = true; 
$dom->Load('C:/wamp/www/xml/test1.xml'); 

$root = $dom->firstChild; 
$list = $root->childNodes->item(1); 


if(isset($_POST['submit'])){ 

    $artistName = $_POST['name']; 
    $track = $_POST['track']; 
    $row = $dom->createElement('row'); 
    $list->appendChild($row); 
    $song = $dom->createElement('song'); 
    $row->appendChild($song); 
    $song->setAttribute('artist', $artistName); 
    $wcm_node = $dom->createTextNode($track); 
    $song->appendChild($wcm_node); 
} 

// Code to format XML after appending data 
$outXML = $dom->saveXML(); // put string in outXML 

//now create a brand new XML document 
$xml = new DOMDocument(); 
$xml->preserveWhiteSpace = false; 
$xml->formatOutput = true; //yup, going to try to make this format again 
//pass the output of the first bunch of stuff we did to the new XML document: 
$xml->loadXML($outXML); 
//now display the cleanly formatted output without using LIBXML_NOBLANKS (which may have undesired consequences 
$xml->save('test1.xml'); // save as file 

} 

?> 

请让我知道，我怎么能做到这一点。

感谢

Answer 1

那不是追加但前面加。 DOM有一个方法，也：

• DOMNode::insertBefore — Adds a new child before a reference node

例（demo）：

$dom = new DOMDocument; 
$dom->loadXml('<rows><row xml:id="r1"/></rows>'); 
$dom->documentElement->insertBefore(
    $dom->createElement('row', 'new row'), 
    $dom->getElementById('r1') 
); 
$dom->formatOutput = TRUE; 
echo $dom->saveXml(); 

输出：

<?xml version="1.0"?> 
<rows> 
    <row>new row</row> 
    <row xml:id="r1"/> 
</rows>