Registration

Plugins are the foundation for adding new features to the CMS by extending it. This article describes the component registration. The registration process allows plugins to declare their features such as components or back-end menus and pages. Some examples of what a plugin can do:

1. Define components.
2. Define user permissions.
3. Add settings pages, menu items, lists and forms.
4. Create database table structures and seed data.
5. Alter functionality of the core or other plugins.
6. Provide classes, back-end controllers, views, assets, and other files.

# Directory structure

Plugins reside in the /plugins subdirectory of the application directory. An example of a plugin directory structure:

plugins/
  acme/              <=== Author name
    blog/            <=== Plugin name
      classes/
      components/
      controllers/
      models/
      updates/
      ...
      Plugin.php     <=== Plugin registration file

Not all plugin directories are required. The only required file is the Plugin.php described below. If your plugin provides only a single component, your plugin directory could be much simpler, like this:

plugins/
  acme/              <=== Author name
    blog/            <=== Plugin name
      components/
      Plugin.php     <=== Plugin registration file

Note: if you are developing a plugin for the Marketplace (opens new window), the updates/version.yaml file is required.

# Plugin namespaces

Plugin namespaces are very important, especially if you are going to publish your plugins on the October Marketplace (opens new window). When you register as an author on the Marketplace you will be asked for the author code which should be used as a root namespace for all your plugins. You can specify the author code only once, when you register. The default author code offered by the Marketplace consists of the author first and last name: JohnSmith. The code cannot be changed after you register. All your plugin namespaces should be defined under the root namespace, for example \JohnSmith\Blog.

# Registration file

The Plugin.php file, called the Plugin registration file, is an initialization script that declares a plugin's core functions and information. Registration files can provide the following:

1. Information about the plugin, its name, and author.
2. Registration methods for extending the CMS.

Registration scripts should use the plugin namespace. The registration script should define a class with the name Plugin that extends the \System\Classes\PluginBase class. The only required method of the plugin registration class is pluginDetails. An example Plugin registration file:

namespace Acme\Blog;

class Plugin extends \System\Classes\PluginBase
{
    public function pluginDetails()
    {
        return [
            'name' => 'Blog Plugin',
            'description' => 'Provides some really cool blog features.',
            'author' => 'ACME Corporation',
            'icon' => 'icon-leaf'
        ];
    }

    public function registerComponents()
    {
        return [
            'Acme\Blog\Components\Post' => 'blogPost'
        ];
    }
}

# Registration methods

The following methods are supported in the plugin registration class:

# Basic plugin information

The pluginDetails is a required method of the plugin registration class. It should return an array containing the following keys:

# Routing and initialization

Plugin registration files can contain two methods boot and register. With these methods you can do anything you like, like register routes or attach handlers to events.

The register method is called immediately when the plugin is registered. The boot method is called right before a request is routed. So if your actions rely on another plugin, you should use the boot method. For example, inside the boot method you can extend models:

public function boot()
{
    User::extend(function($model) {
        $model->hasOne['author'] = ['Acme\Blog\Models\Author'];
    });
}

Note: The boot and register methods are not called during the update process to protect the system from critical errors. To overcome this limitation use elevated permissions.

Plugins can also supply a file named routes.php that contain custom routing logic, as defined in the router service. For example:

Route::group(['prefix' => 'api_acme_blog'], function() {

    Route::get('cleanup_posts', function(){ return Posts::cleanUp(); });

});

# Dependency definitions

A plugin can depend upon other plugins by defining a $require property in the Plugin registration file, the property should contain an array of plugin names that are considered requirements. A plugin that depends on the Acme.User plugin can declare this requirement in the following way:

namespace Acme\Blog;

class Plugin extends \System\Classes\PluginBase
{
    /**
     * @var array Plugin dependencies
     */
    public $require = ['Acme.User'];

    [...]
}

Dependency definitions will affect how the plugin operates and how the update process applies updates. The installation process will attempt to install any dependencies automatically, however if a plugin is detected in the system without any of its dependencies it will be disabled to prevent system errors.

Dependency definitions can be complex but care should be taken to prevent circular references. The dependency graph should always be directed and a circular dependency is considered a design error.

# Extending Twig

Custom Twig filters and functions can be registered in the CMS with the registerMarkupTags method of the plugin registration class. The next example registers two Twig filters and two functions.

public function registerMarkupTags()
{
    return [
        'filters' => [
            // A global function, i.e str_plural()
            'plural' => 'str_plural',

            // A local method, i.e $this->makeTextAllCaps()
            'uppercase' => [$this, 'makeTextAllCaps']
        ],
        'functions' => [
            // A static method call, i.e Form::open()
            'form_open' => ['October\Rain\Html\Form', 'open'],

            // Using an inline closure
            'helloWorld' => function() { return 'Hello World!'; }
        ]
    ];
}

public function makeTextAllCaps($text)
{
    return strtoupper($text);
}

# Navigation menus

Plugins can extend the back-end navigation menus by overriding the registerNavigation method of the Plugin registration class. This section shows you how to add menu items to the back-end navigation area. An example of registering a top-level navigation menu item with two sub-menu items:

public function registerNavigation()
{
    return [
        'blog' => [
            'label'       => 'Blog',
            'url'         => Backend::url('acme/blog/posts'),
            'icon'        => 'icon-pencil',
            'permissions' => ['acme.blog.*'],
            'order'       => 500,
            // Set counter to false to prevent the default behaviour of the main menu counter being a sum of
            // its side menu counters
            'counter'     => ['\Author\Plugin\Classes\MyMenuCounterService', 'getBlogMenuCount'],
            'counterLabel'=> 'Label describing a dynamic menu counter',
            // Optionally you can set a badge value instead of a counter to display a string instead of a numerical counter
            'badge'       => 'New'

            'sideMenu' => [
                'posts' => [
                    'label'       => 'Posts',
                    'icon'        => 'icon-copy',
                    'url'         => Backend::url('acme/blog/posts'),
                    'permissions' => ['acme.blog.access_posts'],
                    'counter'     => 2,
                    'counterLabel'=> 'Label describing a static menu counter',
                ],
                'categories' => [
                    'label'       => 'Categories',
                    'icon'        => 'icon-copy',
                    'url'         => Backend::url('acme/blog/categories'),
                    'permissions' => ['acme.blog.access_categories'],
                ]
            ]
        ]
    ];
}

When you register the back-end navigation you can use localization strings for the label values. Back-end navigation can also be controlled by the permissions values and correspond to defined back-end user permissions. The order in which the back-end navigation appears on the overall navigation menu items, is controlled by the order value. Higher numbers mean that the item will appear later on in the order of menu items while lower numbers mean that it will appear earlier on.

To make the sub-menu items visible, you may set the navigation context in the back-end controller using the BackendMenu::setContext method. This will make the parent menu item active and display the children in the side menu.

# Registering middleware

To register a custom middleware, you can apply it directly to a Backend controller in your plugin by using Controller middleware, or you can extend a Controller class by using the following method.

public function boot()
{
    \Cms\Classes\CmsController::extend(function($controller) {
        $controller->middleware('Path\To\Custom\Middleware');
    });
}

Alternatively, you can push it directly into the Kernel via the following.

public function boot()
{
    // Add a new middleware to beginning of the stack.
    $this->app['Illuminate\Contracts\Http\Kernel']
         ->prependMiddleware('Path\To\Custom\Middleware');

    // Add a new middleware to end of the stack.
    $this->app['Illuminate\Contracts\Http\Kernel']
         ->pushMiddleware('Path\To\Custom\Middleware');
}

# Elevated permissions

By default plugins are restricted from accessing certain areas of the system. This is to prevent critical errors that may lock an administrator out from the back-end. When these areas are accessed without elevated permissions, the boot and register initialization methods for the plugin will not fire.

Define the $elevated property to grant elevated permissions for your plugin.

/**
 * @var bool Plugin requires elevated permissions.
 */
public $elevated = true;