# The Module Class

By default, the module system expects each module name to be capable of
resolving to an object instance. The default module resolver,
`Zend\ModuleManager\Listener\ModuleResolverListener`, instantiates an instance
of `{moduleName}\Module` for each enabled module.

## A Minimal Module

As an example, provided the module name "MyModule",
`Zend\ModuleManager\Listener\ModuleResolverListener` will expect the class
`MyModule\Module` to be available. It relies on a registered autoloader
(typically `Zend\Loader\ModuleAutoloader`) to find and include the
`MyModule\Module` class if it isn't already available.

The directory structure of a module named "MyModule" might start out looking
something like this:

```text
MyModule/
    Module.php
```

Within `Module.php`, you define your `MyModule\Module` class:

```php
namespace MyModule;

class Module
{
}
```

Though it will not serve any purpose at this point, this "MyModule" module now
has everything required to be considered a valid module and to be loaded by the
module system!

This `Module` class serves as the single entry point for `ModuleManager`
listeners to interact with a module. From within this class, modules can
override or provide additional application configuration, perform initialization
tasks such as registering autoloader(s), services and event listeners, declaring
dependencies, and much more.

## A Typical Module Class

The following example shows a more typical usage of the `Module` class:

```php
namespace MyModule;

class Module
{
    public function getAutoloaderConfig()
    {
        return [
            'Zend\Loader\ClassMapAutoloader' => [
                __DIR__ . '/autoload_classmap.php',
            ],
            'Zend\Loader\StandardAutoloader' => [
                'namespaces' => [
                    __NAMESPACE__ => __DIR__ . '/src/' . __NAMESPACE__,
                ],
            ],
        ];
    }

    public function getConfig()
    {
        return include __DIR__ . '/config/module.config.php';
    }
}
```

For a list of the provided module manager listeners and the interfaces and methods that `Module`
classes may implement in order to interact with the module manager and application, see the
[module manager listeners](module-manager.md#module-manager-listeners) and the
[module mananger events](module-manager.md#module-manager-events) documentation.

## The loadModules.post Event

It is not safe for a module to assume that any other modules have already been
loaded at the time `init()` method is called. If your module needs to perform
any actions after all other modules have been loaded, use the module manager's
`loadModules.post`.

> ### Event information
>
> For more information on methods like `init()` and `getConfig()`, refer to the
> [module manager listeners documentation](module-manager.md#module-manager-listeners).

### Sample Usage of "loadModules.post" Event

```php
use Zend\EventManager\EventInterface as Event;
use Zend\ModuleManager\ModuleManager;

class Module
{
    public function init(ModuleManager $moduleManager)
    {
        // Remember to keep the init() method as lightweight as possible
        $events = $moduleManager->getEventManager();
        $events->attach('loadModules.post', [$this, 'modulesLoaded']);
    }

    public function modulesLoaded(Event $e)
    {
        // This method is called once all modules are loaded.
        $moduleManager = $e->getTarget();
        $loadedModules = $moduleManager->getLoadedModules();

        // To get the configuration from another module named 'FooModule'
        $config = $moduleManager->getModule('FooModule')->getConfig();
    }
}
```

> ### Use init() sparingly
>
> The `init()` method is called for **every** module implementing this feature,
> on **every** page request, and should **only** be used for performing
> **lightweight** tasks such as registering event listeners.

## The MVC "bootstrap" Event

If you are writing an MVC-oriented module, you may need access to additional
parts of the application in your `Module` class such as the instance of
`Zend\Mvc\Application` or its registered `ServiceManager` instance. For this,
you may utilize the MVC `bootstrap` event. The bootstrap event is triggered
after the `loadModule.post` event, once `$application->bootstrap()` is called.

### Sample Usage of the MVC "bootstrap" Event

```php
use Zend\EventManager\EventInterface as Event;

class Module
{
    public function onBootstrap(Event $e)
    {
        // This method is called once the MVC bootstrapping is complete
        $application = $e->getApplication();
        $services    = $application->getServiceManager();
    }
}
```

> ### Use onBootstrap() sparingly
>
> The `onBootstrap()` method is called for **every** module implementing this
> feature, on **every** page request, and should **only** be used for performing
> **lightweight** tasks such as registering event listeners.
