Request and response handling in Wordpress - Mini Project: Build & Apply

Request and Response Handling in WordPress

📖 Scenario: You are building a simple WordPress plugin that handles a custom HTTP request and sends a JSON response. This is useful when you want to create an API endpoint or handle AJAX requests in WordPress.

🎯 Goal: Create a WordPress plugin that registers a custom REST API endpoint at /wp-json/custom/v1/message which returns a JSON response with a greeting message.

📋 What You'll Learn

Create a function to register a REST API route

Add a callback function that returns a JSON response

Use WordPress REST API functions to handle the request and response

Register the route on the rest_api_init action hook

💡 Why This Matters

🌍 Real World

Custom REST API endpoints are used to extend WordPress functionality, allowing integration with other apps, mobile clients, or custom frontends.

💼 Career

Understanding how to handle requests and responses in WordPress REST API is essential for WordPress plugin developers and backend developers working with WordPress.

1

Create the plugin header and initial function

Create a PHP file with the plugin header comment and define a function called custom_register_route that will later register the REST API route.

Wordpress

<?php
// Your code here

Need a hint?

Start by creating a PHP file with the plugin header comment and define an empty function named custom_register_route.

2

Add the REST API route registration

Inside the custom_register_route function, use register_rest_route to register a route with namespace custom/v1 and route /message. Set the methods to GET and the callback to custom_message_callback.

Wordpress

<?php
/**
 * Plugin Name: Custom REST API Message
 * Description: A plugin to create a custom REST API endpoint that returns a greeting message.
 * Version: 1.0
 * Author: Your Name
 */

function custom_register_route() {
    // Register the REST API route here
}

Need a hint?

Use register_rest_route inside the function to define the route, HTTP method, and callback function.

3

Create the callback function to return JSON response

Create a function called custom_message_callback that returns an array with a key message and value 'Hello from custom REST API!'. This array will be automatically converted to JSON by WordPress.

Wordpress

 'GET',
        'callback' => 'custom_message_callback',
    ));
}

// Create the callback function here
# Your code here

Need a hint?

Define the callback function that returns an array with the greeting message.

4

Hook the route registration to rest_api_init

Add an action hook to call custom_register_route on the rest_api_init action so WordPress registers the route when the REST API initializes.

Wordpress

 'GET',
        'callback' => 'custom_message_callback',
    ));
}

function custom_message_callback() {
    return array('message' => 'Hello from custom REST API!');
}

// Hook the route registration here
# Your code here

Need a hint?

Use add_action to connect your route registration function to the rest_api_init hook.