README

PSR-0 and PSR-4 compliant autoloader for PHP 8.0+

Why Horde Autoloader?

Horde Autoloader predates PSR-0 and is mostly maintained for legacy and educational purposes. Horde itself primarily uses composer autoloader as does everybody else. Remaining calls into Horde Autoloader from the Horde Framework are going to be removed step by step.

If you need a config-is-code, self-contained, PSR-0 capable autoloader and composer autoloader is not an option, give it a try. Your reasons are yours.

Features

PSR-4 Support - Autoloading with namespaces
PSR-0 Support - PEAR-style autoloading without namespaces, underscores as subdir separators.
Classpath Mappers - Application, Prefix, PrefixString patterns
PHP 8.0+ - Full type safety and modern features
LIFO Ordering - Last-added mapper searched first
Callback Support - Execute code after class loads
No Dependencies - Self-contained library

Quick Start

Modern (PSR-4 with PSR-0 support)

// Autoloader bootstraps itself - require files explicitly
require_once __DIR__ . '/vendor/horde/autoloader/src/Autoloader.php';
require_once __DIR__ . '/vendor/horde/autoloader/src/ClassPathMapper/Psr4.php';

use Horde\Autoloader\Autoloader;
use Horde\Autoloader\ClassPathMapper\Psr4;

$autoloader = new Autoloader();
$psr4 = new Psr4(enablePsr0Fallback: false);
$psr4->addNamespace('Acme\Log', __DIR__ . '/vendor/acme/log/src');
$autoloader->addClassPathMapper($psr4);
$autoloader->registerAutoloader();

Legacy (PSR-0 based PSR-0)

// Autoloader bootstraps itself - require files explicitly
require_once __DIR__ . '/vendor/horde/autoloader/lib/Horde/Autoloader.php';

$autoloader = new Horde_Autoloader();
$autoloader->addClassPathMapper(
    new Horde_Autoloader_ClassPathMapper_Default(__DIR__ . '/lib')
);
$autoloader->registerAutoloader();

Installation

composer require horde/autoloader

Documentation

Examples (Legacy PSR-0) - PSR-0 usage examples
Examples (Modern) - PSR-4 and modern features
Upgrading Guide - Migration from PSR-0 to PSR-4
Changelog - Version history

Requirements

PHP 8.0 or higher

Key Differences: PSR-0 vs PSR-4

Feature	PSR-0	PSR-4
Underscores	Converted to `/`	Preserved as-is
Namespace mapping	Simple path	Prefix → base directory
Top-level classes	Allowed	Rejected (requires namespace)
Multiple base dirs	No	Yes

PSR-0 Example

// Class: Vendor_Package_Class_Name
// Maps to: vendor/Vendor/Package/Class/Name.php

PSR-4 Example

// Prefix: Vendor\Package → /vendor/package/src
// Class: \Vendor\Package\Class_Name
// Maps to: /vendor/package/src/Class_Name.php (underscore preserved!)

Available Mappers

Modern (src/)

Psr4 - PSR-4 compliant autoloader with namespace prefix mapping
DefaultMapper - PSR-0 compliant mapper (underscores → directories)
Application - Application-specific MVC pattern mapper
Prefix - Regex-based prefix matching
PrefixString - Fast case-insensitive string prefix matching

Legacy (lib/)

Horde_Autoloader_ClassPathMapper_Default - PSR-0 mapper
Horde_Autoloader_ClassPathMapper_Application - Application mapper
Horde_Autoloader_ClassPathMapper_Prefix - Regex prefix
Horde_Autoloader_ClassPathMapper_PrefixString - String prefix

Testing

# Run all tests
phpunit

# Run specific test suites
phpunit --testsuite unit        # Legacy PSR-0 tests
phpunit --testsuite modern      # Modern PSR-4 tests
phpunit --testsuite integration # Real file loading tests

License

LGPL-2.1-only

Credits

Authors: Bob Mckee, Chuck Hagenbuch
Maintainers: Jan Schneider, Ralf Lang

horde / autoloader

Maintainers

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