What Are PHP libxml Functions? | Happy Coders

What Are PHP libxml Functions?

August 4, 2025

libxml functions in PHP are used for working with XML data. These functions are built on top of the libxml2 C library, which provides parsing, validation, and error handling for XML documents.

Mainly used with:

DOMDocument
SimpleXML
XMLReader / XMLWriter

Common libxml Functions

Function	Purpose
`libxml_use_internal_errors()`	Suppress/handle XML errors internally
`libxml_get_errors()`	Get all collected XML parsing errors
`libxml_clear_errors()`	Clear the libxml error buffer
`libxml_disable_entity_loader()`	Prevent XXE attacks (security)
`libxml_get_last_error()`	Get the last XML parsing error
`libxml_set_streams_context()`	Set stream context for XML loading

File Name: libxml-example.php


<?php
libxml_use_internal_errors(true); // prevent warnings

$xmlString = 'Tina'; // broken XML

$xml = simplexml_load_string($xmlString);

if (!$xml) {
    echo "Failed to load XML:\n";
    foreach (libxml_get_errors() as $error) {
        echo $error->message;
    }
    libxml_clear_errors();
}
?>

Use Case Example: Prevent XML Injection


libxml_disable_entity_loader(true); // Disables external entities

This prevents XXE (XML External Entity) vulnerabilities when loading untrusted XML.

Summary

Task	Function
Enable custom XML error handling	`libxml_use_internal_errors(true)`
Retrieve errors	`libxml_get_errors()`
Clear error buffer	`libxml_clear_errors()`
Prevent XML attacks	`libxml_disable_entity_loader()`
Set custom stream context	`libxml_set_streams_context()`