How to validate xml with php

Question

I have made an api with xml based request for my website.

but sometimes, some customers send me an invalid xml and I want to return a good response.

how can I validate xml?

edited:

Ok, I think I asked wrong question, I want to validate nodes and if some nodes missing then I return best response.

I used to validate this with php and I have to check every nodes. but this way is very hard to modify.

it is my xml example:

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<mashhadhost>
    <create>
        <name>example.ir</name>
        <period>60</period>
        <ns>
            <hostAttr>
                <hostName>ns1.example.ir</hostName>
                <hostAddr ip="v4">192.0.2.2</hostAddr>
            </hostAttr>
        </ns>
        <contact type="holder">ex61-irnic</contact>
        <contact type="admin">ex61-irnic</contact>
        <contact type="tech">ex61-irnic</contact>
        <contact type="bill">ex61-irnic</contact>
    </create>
    <auth>
        <code>TOKEN</code>
    </auth>
</mashhadhost>

Answer 1

Unfortunately XMLReader didn't validate lots of things in my case.

Here a small piece of class I wrote a while ago:

/**
 * Class XmlValidator
 * @author Francesco Casula <[email protected]>
 */
class XmlValidator
{
    /**
     * @param string $xmlFilename Path to the XML file
     * @param string $version 1.0
     * @param string $encoding utf-8
     * @return bool
     */
    public function isXMLFileValid($xmlFilename, $version = '1.0', $encoding = 'utf-8')
    {
        $xmlContent = file_get_contents($xmlFilename);
        return $this->isXMLContentValid($xmlContent, $version, $encoding);
    }

    /**
     * @param string $xmlContent A well-formed XML string
     * @param string $version 1.0
     * @param string $encoding utf-8
     * @return bool
     */
    public function isXMLContentValid($xmlContent, $version = '1.0', $encoding = 'utf-8')
    {
        if (trim($xmlContent) == '') {
            return false;
        }

        libxml_use_internal_errors(true);

        $doc = new DOMDocument($version, $encoding);
        $doc->loadXML($xmlContent);

        $errors = libxml_get_errors();
        libxml_clear_errors();

        return empty($errors);
    }
}

It works fine with streams and vfsStream as well for testing purposes.

Answer 2

The PHP documentation has exactly what you need!

XML DOMDocument::validate

I'm sure that you have already defined the proper DTD, right?

<?php
$dom = new DOMDocument;
$dom->Load('book.xml');
if ($dom->validate()) {
    echo "This document is valid!\n";
}
?>