PHP | DOMDocument schemaValidate() Function

The DOMDocument::schemaValidate() function is an inbuilt function in PHP which is used to validate a document based on the given schema file. The schema file can be in an XSD format which is the recommendation from W3C (World Wide Web Consortium).

Syntax:

bool DOMDocument::schemaValidate( string $filename, int $flags = 0 )

Parameters: This function accept two parameters as mentioned above and described below:

• $filename: It specifies the path to the schema.
• $flags (Optional): It specifies the validation flags.

Return Value: This function returns TRUE on success or False on failure.

Below given programs illustrate the DOMDocument::schemaValidate() function in PHP:

Program 1:

• File name: rule.xsd

  <?xml version="1.0"?>
  <xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"
  elementFormDefault="qualified">
      <xs:element name="student">
          <xs:complexType>
              <xs:sequence>
                  <xs:element name="name" type="xs:string"/>
                  <xs:element name="rollno" type="xs:integer"/>
              </xs:sequence>
          </xs:complexType>
      </xs:element>
  </xs:schema>
• File name: index.php

  <?php
  
  // Create a new DOMDocument
  $doc = new DOMDocument;
  
  // Load the XML
  $doc->loadXML("<?xml version=\"1.0\"?>
  <student>
      <name>Rahul </name>
      <rollno>34</rollno>
  </student>");
  
  // Check if XML follows the rule
  if ($doc->schemaValidate('rule.xsd')) {
      echo "This document is valid!\n";
  }
  ?>
• Output:

  This document is valid!

Program 2:

• File name: rule.xsd

  <?xml version="1.0"?>
  <xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"
  elementFormDefault="qualified">
      <xs:element name="body">
          <xs:complexType>
              <xs:sequence>
                  <xs:element name="h1" type="xs:string"/>
                  <xs:element name="strong" type="xs:integer"/>
              </xs:sequence>
          </xs:complexType>
      </xs:element>
  </xs:schema>
• File name: index.php

  <?php
  
  // Create a new DOMDocument
  $doc = new DOMDocument;
  
  // Load the XML
  $doc->loadXML("<?xml version=\"1.0\"?>
  <student>
      <h1>Rahul </h1>
  </student>");
  
  // Check if XML follows the rule
  if (!$doc->schemaValidate('rule.xsd')) {
      echo "This document is not valid!\n";
  }
  ?>
• Output:

  This document is not valid!

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