XmlXsdValidator

<?php

namespace App\Helpers;

use DOMDocument;
use InvalidArgumentException;
use UnexpectedValueException;

class XmlXsdValidator
{
    /**
     * XmlXsdValidator constructor.
     */
    public function __construct()
    {
        // Enable user error handling
        libxml_use_internal_errors(true);
    }

    /**
     * Method to validate raw xml data against specified xsd schema.
     *
     * @param $xmlString
     * @param $xsdSchemaPath
     * @return bool
     * @throws Exception
     */
    public function validate($xmlString, $xsdSchemaPath)
    {
        // Validate xml string
        if (empty($xmlString)) {
            throw new InvalidArgumentException('Empty xml string.');
        }

        // Validate xsd schema path
        if (!file_exists($xsdSchemaPath)) {
            throw new InvalidArgumentException('XSD schema file '. (!empty($xsdSchemaPath) ? $xsdSchemaPath : 'N/A') .' does not exist.');
        }

        // Load xml string
        $xml = new DOMDocument();
        $xml->loadXML($xmlString);

        // Validate xml string against xsd schema
        if (!$xml->schemaValidate($xsdSchemaPath))
        {
            // Init validation errors
            $validation_errors = [];

            // Load validation errors
            $errors = libxml_get_errors();

            // Parse validation error messages
            foreach ($errors as $error)
            {
                // Parse error type
                $error_type = '';
                switch ($error->level) {
                    case LIBXML_ERR_WARNING:
                        $error_type = "Warning $error->code: ";
                        break;
                    case LIBXML_ERR_ERROR:
                        $error_type = "Error $error->code: ";
                        break;
                    case LIBXML_ERR_FATAL:
                        $error_type = "Fatal Error $error->code: ";
                        break;
                }

                // Build validation error
                $validation_error = $error_type . $error->message;
                if ($error->file) {
                    $validation_error .= ' on file ' . basename($error->file);
                }
                $validation_error .= ' on line #' . $error->line;

                // Append validation error
                $validation_errors[] = $validation_error;
            }

            // Clean-up
            libxml_clear_errors();

            // Error
            throw new UnexpectedValueException('XML validation failed: ' . implode(' | ', $validation_errors));
        }

        // Clean-up
        $xml = null;

        // Success
        return true;
    }
}