コントローラ・クラス

class My_REST_Posts_Controller {

	// Here initialize our namespace and resource name.
	public function __construct() {
		$this->namespace     = '/my-namespace/v1';
		$this->resource_name = 'posts';
	}

	// Register our routes.
	public function register_routes() {
		register_rest_route( $this->namespace, '/' . $this->resource_name, array(
			// Here we register the readable endpoint for collections.
			array(
				'methods'   => 'GET',
				'callback'  => array( $this, 'get_items' ),
				'permission_callback' => array( $this, 'get_items_permissions_check' ),
			),
			// Register our schema callback.
			'schema' => array( $this, 'get_item_schema' ),
		) );
		register_rest_route( $this->namespace, '/' . $this->resource_name . '/(?P<id>[\d]+)', array(
			// Notice how we are registering multiple endpoints the 'schema' equates to an OPTIONS request.
			array(
				'methods'   => 'GET',
				'callback'  => array( $this, 'get_item' ),
				'permission_callback' => array( $this, 'get_item_permissions_check' ),
			),
			// Register our schema callback.
			'schema' => array( $this, 'get_item_schema' ),
		) );
	}

	/**
	 * Check permissions for the posts.
	 *
	 * @param WP_REST_Request $request Current request.
	 */
	public function get_items_permissions_check( $request ) {
		if ( ! current_user_can( 'read' ) ) {
			return new WP_Error( 'rest_forbidden', esc_html__( 'You cannot view the post resource.' ), array( 'status' => $this->authorization_status_code() ) );
		}
		return true;
	}

	/**
	 * Grabs the five most recent posts and outputs them as a rest response.
	 *
	 * @param WP_REST_Request $request Current request.
	 */
	public function get_items( $request ) {
		$args = array(
			'post_per_page' => 5,
		);
		$posts = get_posts( $args );

		$data = array();

		if ( empty( $posts ) ) {
			return rest_ensure_response( $data );
		}

		foreach ( $posts as $post ) {
			$response = $this->prepare_item_for_response( $post, $request );
			$data[] = $this->prepare_response_for_collection( $response );
		}

		// Return all of our comment response data.
		return rest_ensure_response( $data );
	}

	/**
	 * Check permissions for the posts.
	 *
	 * @param WP_REST_Request $request Current request.
	 */
	public function get_item_permissions_check( $request ) {
		if ( ! current_user_can( 'read' ) ) {
			return new WP_Error( 'rest_forbidden', esc_html__( 'You cannot view the post resource.' ), array( 'status' => $this->authorization_status_code() ) );
		}
		return true;
	}

	/**
	 * Grabs the five most recent posts and outputs them as a rest response.
	 *
	 * @param WP_REST_Request $request Current request.
	 */
	public function get_item( $request ) {
		$id = (int) $request['id'];
		$post = get_post( $id );

		if ( empty( $post ) ) {
			return rest_ensure_response( array() );
		}

		$response = prepare_item_for_response( $post );

		// Return all of our post response data.
		return $response;
	}

	/**
	 * Matches the post data to the schema we want.
	 *
	 * @param WP_Post $post The comment object whose response is being prepared.
	 */
	public function prepare_item_for_response( $post, $request ) {
		$post_data = array();

		$schema = $this->get_item_schema( $request );

		// We are also renaming the fields to more understandable names.
		if ( isset( $schema['properties']['id'] ) ) {
			$post_data['id'] = (int) $post->ID;
		}

		if ( isset( $schema['properties']['content'] ) ) {
			$post_data['content'] = apply_filters( 'the_content', $post->post_content, $post );
		}

		return rest_ensure_response( $post_data );
	}

	/**
	 * Prepare a response for inserting into a collection of responses.
	 *
	 * This is copied from WP_REST_Controller class in the WP REST API v2 plugin.
	 *
	 * @param WP_REST_Response $response Response object.
	 * @return array Response data, ready for insertion into collection data.
	 */
	public function prepare_response_for_collection( $response ) {
		if ( ! ( $response instanceof WP_REST_Response ) ) {
			return $response;
		}

		$data = (array) $response->get_data();
		$server = rest_get_server();

		if ( method_exists( $server, 'get_compact_response_links' ) ) {
			$links = call_user_func( array( $server, 'get_compact_response_links' ), $response );
		} else {
			$links = call_user_func( array( $server, 'get_response_links' ), $response );
		}

		if ( ! empty( $links ) ) {
			$data['_links'] = $links;
		}

		return $data;
	}

	/**
	 * Get our sample schema for a post.
	 *
	 * @param WP_REST_Request $request Current request.
	 */
	public function get_item_schema( $request ) {
		$schema = array(
			// This tells the spec of JSON Schema we are using which is draft 4.
			'$schema'              => 'http://json-schema.org/draft-04/schema#',
			// The title property marks the identity of the resource.
			'title'                => 'post',
			'type'                 => 'object',
			// In JSON Schema you can specify object properties in the properties attribute.
			'properties'           => array(
				'id' => array(
					'description'  => esc_html__( 'Unique identifier for the object.', 'my-textdomain' ),
					'type'         => 'integer',
					'context'      => array( 'view', 'edit', 'embed' ),
					'readonly'     => true,
				),
				'content' => array(
					'description'  => esc_html__( 'The content for the object.', 'my-textdomain' ),
					'type'         => 'string',
				),
			),
		);

		return $schema;
	}

	// Sets up the proper HTTP status code for authorization.
	public function authorization_status_code() {

		$status = 401;

		if ( is_user_logged_in() ) {
			$status = 403;
		}

		return $status;
	}
}

// Function to register our new routes from the controller.
function prefix_register_my_rest_routes() {
	$controller = new My_REST_Posts_Controller();
	$controller->register_routes();
}

add_action( 'rest_api_init', 'prefix_register_my_rest_routes' );