README

This library validates electronic invoices (XRechnungen) according to:

• UBL 2.1 structural rules (via XSD validation)
• EN 16931 semantic rules (via Schematron using XSLT 2.0/3.0)

🛠️ Built for use with SaxonC (required for XSLT 3.0 in PHP)

📁 Installation

composer require doards/xrechnung-validator

🚀 Features

• ✅ UBL 2.1 XSD structure validation
• ✅ EN 16931 Schematron validation via XSLT
• ✅ Works with PHP 8.x
• ✅ Clean object-oriented API

📦 Requirements

• PHP 8.1 or higher
• SaxonC 12.x (must be installed and available via saxon.so)
• DOM extension (enabled by default in PHP)
• DYLD_LIBRARY_PATH (macOS) or LD_LIBRARY_PATH (Linux) must include the SaxonC library path

❗ saxon.so must be loaded via php.ini or a custom .ini file

Basic Usage

use Doards\XRechnungValidator\UBLStructureValidation;
use Doards\XRechnungValidator\EN16931Validator;

$xsdPath  = __DIR__ . '/resources/ubl/2.1/xsd/maindoc/UBL-Invoice-2.1.xsd';
$schematronXsltPath = __DIR__ . '/resources/peppol/billing-bis/3.0.18/PEPPOL-EN16931-UBL.xslt';
$xmlFile  = __DIR__ . '/examples/base-example.xml';

// Validate UBL structure
$ublValidator = new UBLStructureValidation($xsdPath);
$ublResult = $ublValidator->validate($xmlFile);

// Validate EN16931 semantic rules
$enValidator = new EN16931Validator($xsltPath);
$enResult = $enValidator->validate($xmlFile);

// Output results
print_r($ublResult);
print_r($enResult);

📄 HTML Report Output Both validators support an optional HTML reporting mode. When enabled, a results.html file will be created (or updated) in the project root.

✅ Example usage with HTML report enabled:

$ublValidator = new UBLStructureValidation($xsdPath);
$ublValidator->validate($xmlFile, true); // Will write UBL results to results.html

$enValidator = new EN16931Validator($xsltPath);
$enValidator->validate($xmlFile, true); // Will append EN results to the same file

The resulting results.html includes:

Clear sections per validation type

Errors (in red)

Warnings (in orange)

Extended Usage

Running Validation from CLI to Avoid macOS / MAMP Fork() Issues

Because SaxonC can cause stability problems in some environments (notably macOS with MAMP + Apache due to fork() issues), it is recommended to run the validation in a separate PHP CLI script instead of directly through the web server.

Example standalone CLI script (xrechnung-valid.php):

<?php
require 'vendor/autoload.php';

use Doards\XRechnungValidator\UBLStructureValidation;
use Doards\XRechnungValidator\EN16931Validator;

// Check if an argument is provided
if (!isset($argv[1])) {
    die("Error: No XML file path provided as an argument.\nUsage: php xrechnung-valid.php <path_to_xml_file>\n");
}

$xmlFile = $argv[1];
$xsdPath = __DIR__ . '/../vendor/doards/xrechnung-validator/resources/ubl/2.1/xsd/maindoc/UBL-Invoice-2.1.xsd';
$schematronXsltPath = __DIR__ . '/../vendor/doards/xrechnung-validator/resources/peppol/billing-bis/3.0.18/PEPPOL-EN16931-UBL.xslt';

$structureValidator = new UBLStructureValidation($xsdPath);
$structureResult = $structureValidator->validate($xmlFile);

$semanticValidator = new EN16931Validator($schematronXsltPath);
$semanticResult = $semanticValidator->validate($xmlFile);

$output = [
    "ublValidation" => $structureResult,
    "invoiceValidation" => $semanticResult,
];

echo json_encode($output);

Then, from your PHP web app or elsewhere, call this script via shell_exec to avoid SaxonC running inside Apache/MAMP:

$phpExecutable = PHP_BINDIR . '/php';
$xmlFile = escapeshellarg($xmlFilePath);
$output = shell_exec("$phpExecutable /path/to/xrechnung-valid.php $xmlFile 2>&1");
$result = json_decode($output, true);

For more info on the macOS fork() issue with SaxonC + PHP see: https://stackoverflow.com/questions/79671062/saxonc-with-php-on-macos-mamp-causes-nsplaceholderset-initialize-crash-via

📄 License

This project is open-source and licensed under the MIT License.

📚 Attribution

This validator makes use of Schematron rules and XSLT stylesheets derived from the official XRechnung validator configuration provided by the KoSIT project:

• https://github.com/itplr-kosit/validator-configuration-bis/tree/master

All rights and licenses for these resources remain with their respective maintainers.