Introduction:

XML (eXtensible Markup Language) is a widely-used data format for structuring and storing information. It is human-readable and machine-parseable, making it an excellent choice for data interchange. When working with XML in PHP, you may encounter situations where you need to include namespaces in your XML files. Namespaces help avoid naming conflicts and organize your XML content effectively.

In this blog, we will explore two methods to convert PHP arrays into XML files with namespaces. We will provide detailed explanations, code examples, and outputs for each method. 

Method 1: Using SimpleXMLElement for Basic XML Generation

Our first method involves using the SimpleXMLElement class, which simplifies the creation and manipulation of XML documents. It's a straightforward approach, suitable for cases where you need a basic XML structure with namespaces.

<?php
// Create a new SimpleXMLElement with a root element and namespace
$xml = new SimpleXMLElement('<root xmlns="http://example.com/xmlns"/>');

// Add data to the XML
$data = [
    'name' => 'John Doe',
    'email' => '[email protected]',
    'age' => 30,
];

foreach ($data as $key => $value) {
    $xml->addChild($key, $value, 'http://example.com/xmlns');
}

// Format the XML
$dom = dom_import_simplexml($xml)->ownerDocument;
$dom->formatOutput = true;

// Output the XML
echo $dom->saveXML();
?>

Output:

<?xml version="1.0"?>
<root xmlns="http://example.com/xmlns">
  <name>John Doe</name>
  <email>[email protected]</email>
  <age>30</age>
</root>

In this example, we create a new SimpleXMLElement with a root element that includes a namespace. We then add data to the XML using the addChild method while specifying the namespace for each element. Finally, we format and output the XML.

Method 2: Using DOMDocument for Advanced XML Manipulation

The second method involves using the DOMDocument class, which provides more control over the XML generation process. This approach is suitable for cases where you need a complex XML structure with namespaces.

<?php
// Create a new DOMDocument
$dom = new DOMDocument('1.0', 'utf-8');

// Create a root element with a namespace
$root = $dom->createElementNS('http://example.com/xmlns', 'root');
$dom->appendChild($root);

// Add data to the XML
$data = [
    'name' => 'John Doe',
    'email' => '[email protected]',
    'age' => 30,
];

foreach ($data as $key => $value) {
    $element = $dom->createElement($key, $value);
    $element->setAttributeNS('http://www.w3.org/2000/xmlns/', 'xmlns', 'http://example.com/xmlns');
    $root->appendChild($element);
}

// Format the XML
$dom->formatOutput = true;

// Output the XML
echo $dom->saveXML();
?>

Output:

<?xml version="1.0" encoding="utf-8"?>
<root xmlns="http://example.com/xmlns">
  <name>John Doe</name>
  <email>[email protected]</email>
  <age>30</age>
</root>

In this method, we create a new DOMDocument and then create a root element with a specified namespace. We add data to the XML using createElement and set the namespace using setAttributeNS. Finally, we format and output the XML.

Method 3: Combining Both Methods for Flexibility

While methods 1 and 2 provide distinct approaches to generating XML with namespaces, you can also combine them for maximum flexibility. This is especially useful when you have complex XML structures with some basic elements. Here's how you can do it:

<?php
// Create a new DOMDocument
$dom = new DOMDocument('1.0', 'utf-8');

// Create a root element with a namespace
$root = $dom->createElementNS('http://example.com/xmlns', 'root');
$dom->appendChild($root);

// Add basic elements using SimpleXMLElement
$basicData = [
    'description' => 'A sample XML document',
    'date' => '2023-10-24',
];

$basicXml = new SimpleXMLElement('<basic xmlns="http://example.com/xmlns"/>');
foreach ($basicData as $key => $value) {
    $basicXml->addChild($key, $value, 'http://example.com/xmlns');
}

$basicDom = dom_import_simplexml($basicXml)->ownerDocument;
$root->appendChild($dom->importNode($basicDom->documentElement, true));

// Add more data to the XML using DOMDocument
$additionalData = [
    'name' => 'John Doe',
    'email' => '[email protected]',
    'age' => 30,
];

foreach ($additionalData as $key => $value) {
    $element = $dom->createElement($key, $value);
    $element->setAttributeNS('http://www.w3.org/2000/xmlns/', 'xmlns', 'http://example.com/xmlns');
    $root->appendChild($element);
}

// Format the XML
$dom->formatOutput = true;

// Output the XML
echo $dom->saveXML();
?>

Output:

<?xml version="1.0" encoding="utf-8"?>
<root xmlns="http://example.com/xmlns">
  <basic xmlns="http://example.com/xmlns">
    <description>A sample XML document</description>
    <date>2023-10-24</date>
  </basic>
  <name>John Doe</name>
  <email>[email protected]</email>
  <age>30</age>
</root>

In this example, we start by creating a basic XML structure using the SimpleXMLElement method and then combine it with the more advanced DOMDocument method to add additional elements. This approach gives you the best of both worlds.

Conclusion:

In this blog, we have covered two methods to convert PHP arrays into XML files with namespaces. The first method uses SimpleXMLElement for basic XML generation, while the second method employs DOMDocument for more advanced XML manipulation. Additionally, we then demonstrated how to combine both methods for flexibility in handling complex XML structures.