Split XML files with PHP not outputting top level parent node - php

Question

I'm trying to separate an XML file into two files, longrentals.xml and shortrentals.xml but have hit a last hurdle I'm stuck on. The following is what I would like to happen:
rentals.xml is parsed and for each instance of term = "short" the top parent "property" node of that entry is saved to shortrentals.xml.
Each instance is removed from the rentals.xml file (after extracting).
The shortrentals.xml file is saved.
The remaining entries in the original file is saved to longrentals.xml.
The XML structure is as follows:
<property>
...
<rent>
<term>short</term>
<freq>week</freq>
<price_peak>5845</price_peak>
<price_high>5845</price_high>
<price_medium>4270</price_medium>
<price_low>3150</price_low>
</rent>
...
</property>
The code I'm using is as follows:
$destination = new DOMDocument;
$destination->preserveWhiteSpace = true;
$destination->loadXML('<?xml version="1.0" encoding="utf-8"?><root></root>');
$source = new DOMDocument;
$source->load('file/rentals.xml');
$xp = new DOMXPath($source);
$destRoot = $destination->getElementsByTagName("root")->item(0);
foreach ($xp->query('/root/property/rent[term = "short"]') as $item) {
$newItem = $destination->importNode($item, true);
$destRoot->appendChild($newItem);
$item->parentNode->removeChild($item);
}
$source->save("file/longrentals.xml");
$destination->formatOutput = true;
$destination->save("file/shortrentals.xml");
This works except the output in shortrentals.xml only contains the rent node not the top level parent Property node. Also the removed entry from longrentals.xml only removes the Rent child node. So, how do I go up a level using my code please?

Answer 1

You can use the parentNode attribute of a DOMNode to go up a level in the structure (similar to how you do it in the removeChild code)...
foreach ($xp->query('/root/property/rent[term = "short"]') as $item) {
$property = $item->parentNode;
$newItem = $destination->importNode($property, true);
$destRoot->appendChild($newItem);
$property->parentNode->removeChild($property);
}

Answer 2

Alternatively, consider XSLT, the special-purpose XML transformation language, to create both such XML files without foreach loops. Here, XSLT is embedded as string but can be parsed from file like any other XML file. Assumed XML structure: <root><property><rent>...
shortrentals.xml output
// Load XML and XSL sources
$xml = new DOMDocument;
$xml->load('file/rentals.xml');
$xslstr = '<?xml version="1.0" ?>
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="1.0">
<xsl:output method="xml" indent="yes"/>
<xsl:strip-space elements="*"/>
<xsl:template match="/root">
<xsl:copy>
<xsl:apply-templates select="property[rent/term=\'short\']"/>
</xsl:copy>
</xsl:template>
<xsl:template match="property">
<xsl:copy>
<xsl:copy-of select="*"/>
</xsl:copy>
</xsl:template>
</xsl:stylesheet>';
$xsl = new DOMDocument;
$xsl->loadXML($xslstr);
// Configure transformer
$proc = new XSLTProcessor;
$proc->importStyleSheet($xsl);
// Transform XML source
$newXML = new DOMDocument;
$newXML = $proc->transformToXML($xml);
// Output file
file_put_contents('file/shortrentals.xml', $newXML);
longrentals.xml (Using Identity Transform and empty template to remove nodes)
// Load XML and XSL sources
$xml = new DOMDocument;
$xml->load('file/rentals.xml');
$xslstr = '<?xml version="1.0" ?>
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="1.0">
<xsl:output method="xml" indent="yes"/>
<xsl:strip-space elements="*"/>
<!-- Identity Transform -->
<xsl:template match="#*|node()">
<xsl:copy>
<xsl:apply-templates select="#*|node()"/>
</xsl:copy>
</xsl:template>
<!-- Remove Non-Short Terms -->
<xsl:template match="property[rent/term=\'short\']"/>
</xsl:stylesheet>';
$xsl = new DOMDocument;
$xsl->loadXML($xslstr);
// Configure transformer
$proc = new XSLTProcessor;
$proc->importStyleSheet($xsl);
// Transform XML source
$newXML = new DOMDocument;
$newXML = $proc->transformToXML($xml);
// Output file
file_put_contents('file/longrentals.xml', $newXML);