Filtering XML file, with PHP

Question

I want to load XML file and then remove all where is bigger/older then 7 years. Date format is YYYY-MM-DD.

Answer 1

You can either use SimpleXML, DOM or XSL for it.

Example XML (shortened for brevity (from Revision 1 of your question)):

$xml = <<< XML
<CriminalCase>
    <Charge>
        <DispositionDate>1995-12-21</DispositionDate>
    </Charge>
    <Charge>
        <DispositionDate>2010-12-21</DispositionDate>
    </Charge>
</CriminalCase>
XML;

---

With SimpleXml

$sevenYearsAgo = new DateTime('-7 years');
$CriminalCase  = new SimpleXmlElement($xml);
for ($i = 0; $i < $CriminalCase->Charge->count(); $i++) {
    $dispositionDate = new DateTime($CriminalCase->Charge->DispositionDate);
    if ($dispositionDate < $sevenYearsAgo) {
        unset($CriminalCase->Charge[$i]);
    }
}
echo $CriminalCase->asXml();

---

With DOM

$dom = new DOMDocument;
$dom->loadXml($xml);
$xpath = new DOMXPath($dom);
$oldCases = $xpath->query(
    sprintf(
        '//Charge[substring-before(DispositionDate, "-") < %d]',
        date('Y', strtotime('-7 years'))
    )
);
foreach ($oldCases as $oldCase) {
    $oldCase->parentNode->removeChild($oldCase);
}
echo $dom->saveXml();

---

With XSLT

<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet version="1.0"
                xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
                xmlns:date="http://exslt.org/dates-and-times"
                extension-element-prefixes="date">

  <xsl:output indent="yes" method="xml"/>
  <xsl:template match="/">
    <CriminalCase>
      <xsl:apply-templates />
    </CriminalCase>      
  </xsl:template>
  <xsl:template match="Charge">
    <xsl:if test="date:year(DispositionDate) &gt; date:year() - 7">
      <xsl:copy-of select="."/>
    </xsl:if>
  </xsl:template>   
</xsl:stylesheet>

and then use this PHP Code to transform it

$doc = new DOMDocument();
$xsl = new XSLTProcessor();
$doc->loadXml($xsl);
$xsl->importStyleSheet($doc);
$doc->loadXml($xml);
echo $xsl->transformToXML($doc);

Answer 2

Here are some tips on how to get started:

1. You need to parse the XML to something a little easier to work with. PHP has a library called SimpleXML.
2. Loop through the data and remove the objects which are older than 7 years. To compare dates you have to first convert the dates you got from the XML to something PHP can process as a date. Take a look at strtotime which gives you the timestamp (seconds since 1970, actually 1901 for version > 5.1.0) or DateTime which supports dates before 1970.
3. To check if the fetched date is older than 7 years ago, you need to (one way) subtract the timestamp with the current timestamp, and see if that value is greater than 7 years in seconds. Or if you use DateTime, you can take a look at DateTime::diff. Remove the objects that you iterate over that are older than 7 years (unset).
4. To save as XML again, take a look at SimpleXMLElement::asXML

Hope that helps!