WireClassLoader / $classLoader

The primary way to register a directory of classes for autoloading. All classes in the given namespace will be looked up in the registered path.

addNamespace($namespace, $path)

// Register a namespace pointing to a directory
$classLoader->addNamespace('ProcessWire', '/path/to/classes/');

// Multiple paths can be registered for a single namespace by calling again
$classLoader->addNamespace('ProcessWire', '/path/to/more-classes/');

All ProcessWire core classes and modules use the ProcessWire namespace. You can optionally register additional paths under ProcessWire if needed, or you can register your own namespace.

// In a module's init() or __construct(), register the module's own directory
public function init() {
    $classLoader = $this->wire()->classLoader;

    // add directory to ProcessWire namespace
    $classLoader->addNamespace('ProcessWire', __DIR__);

    // register a custom namespace directory
    $classLoader->addNamespace('MyNamespace', __DIR__);
}

Once registered, any ProcessWire\ClassName (or MyNamespace\ClassName) class will be found automatically in the registered path when first referenced — no manual require_once needed.

getNamespace()

Returns the registered paths for a namespace, or an empty array if not found.

$paths = $classLoader->getNamespace('ProcessWire');
// ['/path/to/wire/core/', '/path/to/site/modules/', ...]

hasNamespace()

Returns true if the namespace has at least one registered path.

if($classLoader->hasNamespace('MyLibrary')) {
    // namespace is registered
}

removeNamespace()

Removes a namespace registration, optionally for a single path only.

// Remove all paths for a namespace
$classLoader->removeNamespace('MyLibrary');

// Remove a single path only
$classLoader->removeNamespace('MyLibrary', '/path/to/remove/');

A class map provides an explicit ClassName => file mapping for classes in the ProcessWire namespace and is the fastest lookup method since it requires no directory scanning. Added in 3.0.260.

addClassMap()

$classLoader->addClassMap([
    'MyHelper'   => 'helpers/MyHelper.php',
    'MyRenderer' => 'renderers/MyRenderer.php',
], __DIR__ . '/');

If a file entry ends with /, the filename is assumed to be ClassName.php in that directory. If it ends with >, it looks for ClassName/ClassName.php.

$classLoader->addClassMap([
    'MyHelper'   => 'helpers/',  // resolves to helpers/MyHelper.php
    'MyRenderer' => '>',         // resolves to MyRenderer/MyRenderer.php
], __DIR__ . '/');

Prefix and suffix registrations are a fallback mechanism — the class is not required to be in the given path, but the path is added as an additional location to check when the class is not found via namespace or class map lookup.

// Any class starting with "My" will also be searched in this path
$classLoader->addPrefix('My', '/path/to/classes/');

// Any class ending with "Validator" will also be searched in this path
$classLoader->addSuffix('Validator', '/path/to/validators/');

findClassFile()

Returns the full path to the file where a class would be loaded from, or false if not found. Useful for debugging autoload configuration.

$file = $classLoader->findClassFile('ProcessWire\\Wire');
// '/path/to/wire/core/Wire.php'

$file = $classLoader->findClassFile('ProcessWire\\UnknownClass');
// false

• Source file: wire/core/WireClassLoader/WireClassLoader.php
• API variable: $classLoader (also wire()->classLoader or $this->wire()->classLoader)
• Default namespace: All ProcessWire and module classes use the ProcessWire namespace; registering additional paths under it is the most common use case
• PSR-4 similarity: Lookup follows namespace-to-path mapping like PSR-4, but with module awareness — if a class is a known module, the Modules loader handles it instead
• Module autoloading: Modules are loaded automatically via the Modules system; $classLoader is only a consideration for additional helper classes that are not themselves modules
• File extensions: .php is supported by default; additional extensions can be registered with addExtension() if needed