Creating custom endpoints Wordpress

Question

I am having trouble on creating custom endpoints to extend my Wordpress application.

After setting up the WordPress module, I can access the json data through the link given : http://localhost/wordpress/wp-json/

I tested different endpoints inside the document with link: https://developer.wordpress.org/rest-api/reference/

And now I am trying to create my own endpoints, but after many researched I could only find something like

add_action( 'rest_api_init', 'myplugin_register_routes' );

and then

function myplugin_register_routes() {
  register_rest_route( 'myplugin/v1', 'foo', array(
    'methods'  => WP_REST_Server::READABLE,
     'callback' => 'myplugin_serve_route',
  ));
}


function myplugin_serve_route( WP_REST_Request $request ) {
// Do something with the $request
// Return either a WP_REST_Response or WP_Error object
return $response;
}

But indeed where should I add these things? Also, I researched a lots and see the advanced endpoint controller practice, may anyone give a hand on me? Or I need to create my own plugin?

Answer 1

All the code goes to theme's functions.php file, or a plugin. After registered a REST route, it can be accessed via this URL:

www.example.com/wp-json/myplugin/v1/foo

Answer 2

To save other's like me a bit of time, this is exactly what I posted in the function.php file.

/**
 * Custom API
 * 
 * This is our callback function that embeds our phrase in a WP_REST_Response
 */
function prefix_get_endpoint_phrase() {
    // rest_ensure_response() wraps the data we want to return into a WP_REST_Response, and ensures it will be properly returned.
    // I guess here we grab our data in the return method
    return rest_ensure_response( 'Hello World, this is my WordPress REST API' );
}

/**
 * This function is where we register our routes for our example endpoint.
 */
function prefix_register_example_routes() {
    // register_rest_route() handles more arguments but we are going to stick to the basics for now.
    register_rest_route( 'hello-world/v1', '/my-command', array(
        // By using this constant we ensure that when the WP_REST_Server changes our readable endpoints will work as intended.
        'methods'  => WP_REST_Server::READABLE,
        // Here we register our callback. The callback is fired when this endpoint is matched by the WP_REST_Server class.
        'callback' => 'prefix_get_endpoint_phrase',
    ) );
}

add_action( 'rest_api_init', 'prefix_register_example_routes' );

Now go to your browser and type:

http://yoursite.com/wp-json/game-thunder/v1/featured-games

This should help you start creating custom endpoints