Plugins

This article describes plugins and their registration functions. The registration process allows plugins to declare their features such as CMS components or backend navigation and pages. Here are some examples of what a plugin can do.

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

# Directory Structure

Plugins reside in the plugins directory of the application directory. An example of a plugin directory structure is below.

├── plugins
|   └── acme  ← Author Name
|       └── blog  ← Plugin Name
|           ├── classes
|           ├── components
|           ├── controllers
|           ├── models
|           ├── updates
|           └── Plugin.php  ← 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
|       └── blog
|           ├── components
|           └── Plugin.php

# Plugin Namespaces

Plugin namespaces are essential, especially if you are going to publish your plugins on the October CMS 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 create:plugin command generates a plugin folder and basic files for the plugin. The first argument specifies the author and plugin name.

php artisan create:plugin Acme.Blog

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 is below.

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::class => 'blogPost'
        ];
    }
}

# Basic Plugin Information

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

# Booting 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::class;
    });
}

Plugins may also supply a file named init.php that contains custom initialization logic. Below is some example content.

App::before({
    // Logic when the request starts, after routes are registered
});

App::after({
    // Logic the request has finished, after the response is sent
});

# 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 require these plugins
     */
    public $require = ['Acme.User'];

    // ...
}

Dependency definitions will affect how the plugin operates and how the update process applies migrations. 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.

# Version History

It is good practice for plugins to maintain a change log that documents any changes or improvements in the code. In addition to writing notes about changes, this process has the useful ability to execute migration and seed files in their correct order.

The change log is stored in a YAML file called version.yaml inside the updates directory of a plugin, which co-exists with migration and seed files. This example displays a typical plugin updates directory structure:

├── plugins
|   └── author
|       └── myplugin
|           ├── updates
|           |   ├── version.yaml  ← Version File
|           |   ├── create_tables.php  ← Database Script
|           |   ├── seed_the_database.php
|           |   └── create_another_table.php
|           └── Plugin.php

# Plugin Dependencies

Updates are applied in a specific order, based on the defined dependencies in the plugin registration file. Plugins that are dependant will not be updated until all their dependencies have been updated first.

namespace Acme\Blog;

class Plugin extends \System\Classes\PluginBase
{
    public $require = ['Acme.User'];
}

In the example above the Acme.Blog plugin will not be updated until the Acme.User plugin has been fully updated.

# Plugin Version File

The version.yaml file, called the Plugin Version File, contains the version comments and refers to database scripts in the correct order. Please read the Database structure article for information about the migration files. This file is required if you're going to submit the plugin to the Marketplace (opens new window). Here is an example of a plugin version file.

v1.0.1: First version
v1.0.2: Second version
v1.0.3:
    - Update with a migration and seed
    - create_tables.php
    - seed_the_database.php
v2.0.0: Important update
v2.0.1: Latest version

As you can see above, there should be a key that represents the version number followed by the update message, which is either a string or an array containing update messages. For updates that refer to migration or seeding files, lines that are script file names can be placed in any position. An example of a comment with no associated update files.

v1.0.1: A single comment that uses no update scripts.

# Important Updates

Sometimes a plugin needs to introduce features that will break websites already using the plugin. To prevent the changes from being deployed automatically, you should increase the major segment of the version string (major.minor.patch). An example of an important update comment is below.

v2.1.0: This is an important update from v1 that contains breaking changes.

When tagging the new version v2 from a version v1 then the changes are not deployed as part of a regular update. The user must install the plugin again to receive the latest version via Composer.

# Migration and Seed Files

As previously described, updates also define when migration and seed files should be applied. An update line with a comment and updates:

v1.1.1:
    - This update will execute the two scripts below.
    - some_upgrade_file.php
    - some_seeding_file.php

The update file name should use snake_case while the containing PHP class should use CamelCase. For a file named some_upgrade_file.php the corresponding class would be SomeUpgradeFile.

<?php namespace Acme\Blog\Updates;

use Schema;
use October\Rain\Database\Updates\Migration;

/**
 * some_upgrade_file.php
 */
class SomeUpgradeFile extends Migration
{
    ///
}

# See Also