Revise WordPress REST API and WP-CLI

Summary: Revising basics of WordPress REST API and WP-CLI

WordPress REST API

The REST API allows us to interact with WordPress programmatically using HTTP requests. It’s useful for creating, reading, updating, and deleting WordPress content from external applications.

• Endpoints: REST API endpoints are URLs that represent specific data and actions. Each endpoint corresponds to a particular resource (e.g., posts, pages, custom post types).
• Routes: Define the URLs for API requests. Routes are associated with specific HTTP methods (GET, POST, PUT, DELETE).
• Controllers: Handle the logic for processing requests to specific routes. They often include methods to handle CRUD operations.
• Namespaces: Used to group routes and avoid conflicts with other plugins or themes. For example, wp/v2 is a namespace for core WordPress routes.

Common Endpoints

• Posts: /wp-json/wp/v2/posts
• Pages: /wp-json/wp/v2/pages
• Custom Post Types: /wp-json/{namespace}/{post_type}
• Taxonomies: /wp-json/wp/v2/taxonomies
• Users: /wp-json/wp/v2/users

Authentication

• Application Passwords: Used for authenticating API requests. Set up in the WordPress admin under user profile settings.
• OAuth: Another method of authentication, often used for more secure and complex integrations.
• Basic Authentication: Not recommended for production due to security risks. Useful for testing.

Common Methods

• GET: Retrieve data from the API. E.g., list posts or get details of a specific post.
• POST: Create new resources. E.g., add a new post.
• PUT/PATCH: Update existing resources. E.g., modify a post.
• DELETE: Remove resources. E.g., delete a post.

Customization

• Custom Endpoints: Create custom routes and controllers for additional functionality. Use register_rest_route() to define custom routes.
• Response Data: Customize the data returned by endpoints using register_rest_field() or by extending REST controllers.
• Permissions: We can control access to endpoints by specifying permissions in route definitions. Use __return_true for public endpoints or add custom permission callback functions.

function my_custom_route() {
    register_rest_route('my_namespace/v1', '/my_endpoint/', array(
        'methods' => 'GET',
        'callback' => 'my_custom_callback',
    ));
}
add_action('rest_api_init', 'my_custom_route');

function my_custom_callback($data) {
    return new WP_REST_Response('Hello World', 200);
}

WP-CLI

WP-CLI is a command-line interface for managing WordPress installations. It allows us to perform tasks like updating plugins, managing users, and running custom commands from the command line.

Basic Commands

• Core
  • wp core download – Download WordPress core files.
  • wp core update – Update WordPress core.
  • wp core version – Show the current WordPress version.
• Plugins
  • wp plugin list – List installed plugins.
  • wp plugin install <plugin> – Install a plugin.
  • wp plugin activate <plugin> – Activate a plugin.
  • wp plugin update <plugin> – Update a plugin.
• Themes
  • wp theme list – List installed themes.
  • wp theme install <theme> – Install a theme.
  • wp theme activate <theme> – Activate a theme.
• Users
  • wp user list – List users.
  • wp user create <user> <email> – Create a new user.
  • wp user update <user> – Update a user’s details.

Custom Commands

• Add Custom Commands: We can extend WP-CLI by creating custom commands. Define a class with methods for the command functionality and use WP_CLI::add_command() to register it.

if (defined('WP_CLI') && WP_CLI) {
    class My_CLI_Command extends WP_CLI_Command {
        public function example($args, $assoc_args) {
            WP_CLI::success('This is a custom command');
        }
    }

    WP_CLI::add_command('my_command', 'My_CLI_Command');
}