Modules

Understanding Modules

Table of Contents

• Concepts
• The Module Class
• Examples
• Actions and Filters

Concepts - Actions and Filters

Modules are made up of methods that run at certain times during the program's execution. These "certain times" are called Hooks. There are two types of hooks: Actions and Filters.

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Actions are defined points in the code that a module can use to hook in their method. A good example would be an Action called "sleepy_preprocess". This action runs very early in the program's lifecycle allowing you to run code before any templates have been rendered. It can be used to verify that a user has access to a page, or to start pulling content from a web service.

namespace Module\ExampleModule;                     # It's good practice to namespace your module

use \Sleepy\Core\Hook;                              # We need both of these classes 
use \Sleepy\Core\Module;                            # to create a module

class Example1 extends Module                       # All modules must extend the Module class
{
    public $hooks = [
        'sleepy_preprocess' => 'start'              # We are going to use this action -> this method
    ];

    public function start()
    {
        // Check if a user is logged in             # Run some code here... No need to return anything.
    }
}

Hook::register(new Example1());                     # We must register our Modules to the Hook System

---

Filters are similar to Actions, but they are used to modify data. An example of a filter could be "render_placeholder_title". This is the Filter for the placeholder "title". In this example, we might want to add the string " | Website Name" to the end of the titles for SEO purposes.

namespace Module\ExampleModule;                     # It's good practice to namespace your module

use \Sleepy\Core\Hook;                              # We need both of these classes 
use \Sleepy\Core\Module;                            # to create a module

class Example2 extends Module
{
    public $hooks = [
        'render_placeholder_title' => 'addSite'     # We are going to use this filter -> method
    ];

    public function addSite($str)                   # The filter will get the value of the title placeholder as $str
    {
        return $str + ' | Website Name';            # and we return the modified string to the template for use
    }
}

Hook::register(new Example2());                     # We must register our Modules to the Hook System

The Module Class

The Module class is located in the app/sleepy/core folder.

There are two configurable section in the Module class: hooks and environments

abstract class Module
{
    // A list of hooks and methods. e.g. 'sleepy_preprocess'  => 'startMethod',
    public $hooks = [];

    // The module will only execute on environments that are set to true
    public $environments = [
        'dev'   => true,
        'stage' => true,
        'live'  => true
    ];

    ...
}

The hooks section tells the system which methods should be run on which hook points.

The environments section tells the system if the module should be run in the dev/stage/live environments.

Examples

Built-in Actions and Filters