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WordPress Plugin Interface

A simple PHP interface designed to provide a consistent structure for WordPress plugins. It defines a set of methods that any implementing class must adhere to, ensuring uniformity and ease of use across different plugins.

Installation

Simply include the PluginInterface.php file in your project, or install it via Composer:

Usage

Implementing the Plugin Interface

To create a plugin using the Plugin Interface, follow these steps:

1. Implement the PluginInterface: Create a class that implements the PluginInterface. This class will define the behavior of your plugin.

2. Define Class Properties: Define class properties to hold the plugin directory path and URL. These properties will be used as initialization parameters.

3. Implement the init() Method: Implement the init() method to initialize your plugin. Use the class properties to set the plugin directory path and URL.

4. Implement the hooks() Method: Implement the hooks() method to register any WordPress hooks (actions and filters) necessary for your plugin.

Using the Plugin Interface

To use a plugin that implements the Plugin Interface, follow these steps:

1. Initialize the Plugin: Call the init() method of the plugin class, passing the plugin directory path and URL as parameters.

2. Use the Plugin: Once initialized, you can use the plugin as needed. Any hooks registered by the plugin will be automatically executed by WordPress.

Example

Here's an example implementation of a plugin using the Plugin Interface:

Or you can also use the base abstract Implementation, which will include init() and the required properties $plugin_dir_path and $plugin_dir_url

Below is an example of how you can instantiate the plugin class, set the plugin path and url:

Explanation:

1. Include Plugin Interface and Class: The PluginInterface is included to ensure the class adheres to the interface.

2. Get Plugin Directory Path: The wp_plugin_dir_path() function is used to retrieve the directory path of the plugin file (__FILE__). This ensures that the plugin directory path is always accurate.

3. Define Plugin URL: The plugin_dir_url() function is used to construct the URL of the plugin directory. This URL can be used to enqueue scripts, styles, or create links within the plugin.

4. Initialize the Plugin: The init() method of the MyPlugin class is called, passing the plugin directory path and URL as parameters. This initializes an instance of the plugin is in the application.

5. Call hooks() Method: Optionally, the hooks() method of the plugin class can be called to register any WordPress hooks necessary for the plugin's functionality.

Benefits:

• Consistency: By using wp_plugin_dir_path() and plugin_dir_url(), you ensure that the plugin directory path and URL are always accurate and consistent.

• Security: Using wp_plugin_dir_path() ensures that the directory path is properly sanitized and secure, reducing the risk of directory traversal attacks.

• Flexibility: The plugin directory path and URL can be easily retrieved and used throughout the plugin code, allowing for dynamic file and URL generation without hardcoding paths or URLs.

• Compatibility: The use of WordPress functions (wp_plugin_dir_path() and plugin_dir_url()) ensures compatibility with future WordPress updates and changes to the file structure.

using wp_plugin_dir_path() and plugin_dir_url() to set the plugin path and URL provides a robust approach to plugin development.

TraitInstalled

The TraitInstalled on AbstractPlugin provides utility methods to check if a WordPress plugin is installed and active. It helps manage plugin dependencies efficiently.

• Check if a plugin is installed
• Check if a plugin is active
• Retrieve all installed plugins

1. MyPlugin::is_installed($plugin_file)

Checks if a plugin is installed.

• Parameter:
  $plugin_file (string) - Path to the plugin file, e.g., 'example-plugin/example-plugin.php'.

• Returns:
  bool - true if installed, false otherwise.

• Example:

2. MyPlugin::is_active($plugin_file)

Checks if a plugin is active.

• Parameter:
  $plugin_file (string) - Path to the plugin file, e.g., 'example-plugin/example-plugin.php'.

• Returns:
  bool - true if active, false otherwise.

• Example:

3. MyPlugin::get_installed_plugins()

Retrieves all installed plugins.

• Returns:
  array - An array of installed plugins.

• Example:

Example Usage

Check if a plugin is both installed and active:

Benefits of the Interface

• Interface Segregation Principle (ISP): The interface follows the ISP by defining only the essential methods (init() and hooks()), ensuring that implementing classes aren't burdened with unnecessary dependencies.

• Separation of Concerns: The interface separates initialization (init()) from hook registration (hooks()), promoting clearer code organization and making the plugin's behavior easier to understand and maintain.

• Clean Constructor: By keeping the constructor clean, the interface adheres to the Single Responsibility Principle (SRP), ensuring that the class is only responsible for instantiation, which supports better code maintainability.

• Support for Standalone Unit Tests: The clean constructor enables easy standalone unit testing. With minimal initialization logic, the class can be instantiated in isolation for focused testing, improving testability.

• Flexibility in Implementation: The interface's minimal method requirements allow implementing classes the flexibility to achieve desired functionality, accommodating various plugin architectures and implementation strategies while ensuring consistent usage.

• Promotes Dependency Injection: The init() method acts as a form of dependency injection, enabling clients to provide external dependencies (such as plugin directory path and URL) to the implementing class. This fosters decoupling and enhances flexibility and reusability.

License

This project is licensed under the MIT License - see the LICENSE file for details.