PHP | DOMDocument xinclude() Function

The DOMDocument::xinclude() function is an inbuilt function in PHP which is used to substitute the XIncludes in a DOMDocument Object.

Syntax:

int DOMDocument::xinclude( int $options = 0 )

Parameters: This function accepts an optional single parameter $options which holds the libxml parameter.

Return Value: This function returns the number of XIncludes in the document, -1 if some processing failed, or FALSE if there were no substitutions.

Below examples illustrate the DOMDocument::xinclude() function in PHP:

Example 1: In this program, we will include from XML from new.xml to index.php.

• new.xml

  <?xml version='1.0'?>
  <disclaimer>
    <p>
      This is the content from new.xml
      included using xinclude.
    </p>
  </disclaimer>
• index.php

  <?php
  $xml = <<<EOD
  <?xml version="1.0" ?>
  <root xmlns:xi="http://www.w3.org/2001/XInclude">
    <xi:include href="new.xml">
    </xi:include>
  </root>
  EOD;
  
  // Create a new DOMDocument
  $dom = new DOMDocument();
  
  // let's have a nice output
  $dom->preserveWhiteSpace = false;
  $dom->formatOutput = true;
  
  // load the XML string defined above
  $dom->loadXML($xml);
  
  // substitute xincludes
  $dom->xinclude();
  
  echo $dom->saveXML();
  ?>
• Output:

  This is the content from new.xml included using xinclude.

Example 2: In this program, we will add a fallback if xinclude fails.

• index.php

  <?php
  $xml = <<<EOD
  <?xml version="1.0" ?>
  <root xmlns:xi="http://www.w3.org/2001/XInclude">
    <xi:include href="wrong_name.xml">
     <xi:fallback>
      <error>xml not found</error>
     </xi:fallback>
    </xi:include>
  </root>
  EOD;
  
  // Create a new DOMDocument
  $dom = new DOMDocument();
  
  // let's have a nice output
  $dom->preserveWhiteSpace = false;
  $dom->formatOutput = true;
  
  // load the XML string defined above
  $dom->loadXML($xml);
  
  // substitute xincludes
  $dom->xinclude();
  
  echo $dom->saveXML();
  ?>
• Output:

  xml not found

Reference: https://www.php.net/manual/en/domdocument.xinclude.php