XML — Parsers, SimpleXML, Expat & DOM

XML stores structured data in tags. PHP can read XML with SimpleXML (easy), XML Parser (Expat, event-based), or DOMDocument (full tree).

XML Parsers overview

XML stores structured data in tags. PHP can read XML with SimpleXML (easy), XML Parser (Expat, event-based), or DOMDocument (full tree).

Real-life example: XML is a labeled packing list — each <item> tag describes one product in the shipment.

Sample XML

<?xml version="1.0" encoding="UTF-8"?>
<courses>
  <course id="1">
    <title>PHP Fundamentals</title>
    <lessons>32</lessons>
  </course>
  <course id="2">
    <title>MySQL Basics</title>
    <lessons>20</lessons>
  </course>
</courses>

SimpleXML

simplexml_load_file() or simplexml_load_string() turns XML into an object you can traverse with -> and foreach.

Real-life example: SimpleXML is reading a short menu — quick glance, pick items by name.

SimpleXML read

<?php
$xml = simplexml_load_string('<?xml version="1.0"?><root><name>Rishtaara</name></root>');
echo $xml->name;

$books = simplexml_load_file("courses.xml");
foreach ($books->course as $course) {
  echo (string) $course->title . "\n";
}
?>

XML Parser (Expat) and DOM

xml_parser_create() (Expat) fires callbacks on start/end tags — memory efficient for huge files. DOMDocument builds a full editable tree.

Real-life example: Expat is a conveyor belt — items pass one at a time. DOM is spreading the whole puzzle on a table to move pieces.

DOMDocument

<?php
$dom = new DOMDocument();
$dom->load("courses.xml");
$titles = $dom->getElementsByTagName("title");

foreach ($titles as $node) {
  echo $node->textContent . "\n";
}
?>

Expat-style parser (concept)

<?php
$parser = xml_parser_create();
xml_parse_into_struct($parser, file_get_contents("courses.xml"), $values);
xml_parser_free($parser);
print_r($values);
?>