ConnectionController.php

<?php
declare( strict_types=1 );

namespace Automattic\WooCommerce\GoogleListingsAndAds\API\Site\Controllers\MerchantCenter;

use Automattic\WooCommerce\GoogleListingsAndAds\API\Site\Controllers\BaseController;
use Automattic\WooCommerce\GoogleListingsAndAds\API\TransportMethods;

defined( 'ABSPATH' ) || exit;

/**
 * Class ConnectionController
 *
 * @package Automattic\WooCommerce\GoogleListingsAndAds\API\Site\Controllers\MerchantCenter
 */
class ConnectionController extends BaseController {

	/**
	 * Register rest routes with WordPress.
	 */
	public function register_routes(): void {
		$this->register_route(
			'mc/connect',
			[
				[
					'methods'             => TransportMethods::READABLE,
					'callback'            => $this->get_connect_callback(),
					'permission_callback' => $this->get_permission_callback(),
				],
				'schema' => $this->get_api_response_schema_callback(),
			]
		);
	}

	/**
	 * Get the callback function for the connection request.
	 *
	 * @return callable
	 */
	protected function get_connect_callback(): callable {
		return function() {
			return [
				'url' => 'example.com',
			];
		};
	}

	/**
	 * Get the schema for settings endpoints.
	 *
	 * @return array
	 */
	protected function get_schema_properties(): array {
		return [
			'url' => [
				'description' => __( 'Action that should be completed after connection.', 'google-listings-and-ads' ),
				'type'        => 'string',
				'context'     => [ 'view', 'edit' ],
				'readonly'    => true,
			],
		];
	}

	/**
	 * Get the item schema name for the controller.
	 *
	 * Used for building the API response schema.
	 *
	 * @return string
	 */
	protected function get_schema_title(): string {
		return 'merchant_center_connection';
	}
}