Modifications to WordPress REST API responses

<?php
/*
 Plugin name: REST API Modifications
 Description: Make changes to REST API responses
 Version: 1.0
 Author: Erick Hitter
 Author URI: https://ethitter.com/
 License: GPLv2
*/

/*
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 of the License.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
*/

class ETH_REST_API_Mods {
	/**
	 *
	 */
	public static function register_hooks() {
		add_filter( 'rest_prepare_post', array( __CLASS__, 'add_medium_image' ), 10, 3 );
		add_filter( 'sharing_show', array( __CLASS__, 'disable_sharedaddy' ) );
	}

	/**
	 * Add a reference to a post's medium-sized image, when present
	 *
	 * Avoids needing to query API separately for an image
	 */
	public static function add_medium_image( $data, $post, $context ) {
		// Default to no image
		$image_url = false;

		// Find an image, either from featured or attachments
		if ( has_post_thumbnail( $post ) ) {
			$image_url = wp_get_attachment_image_url( get_post_thumbnail_id( $post ), 'medium' );
		} else {
			$children = get_children( array(
				'post_parent'    => $post->ID,
				'post_status'    => 'inherit',
				'post_type'      => 'attachment',
				'order'          => 'ASC',
				'orderby'        => 'menu_order ID',
				'posts_per_page' => 15,
			) );

			foreach ( $children as $child ) {
				if ( wp_attachment_is_image( $child->ID ) ) {
					$image_url = wp_get_attachment_image_url( $child->ID, 'medium' );
					break;
				}
			}
		}

		// Return modified data object
		$data->data['medium_image'] = $image_url;
		return $data;
	}

	/**
	 * Don't include Jetpack's sharing stuff in REST responses
	 */
	public static function disable_sharedaddy( $show ) {
		if ( defined( 'REST_REQUEST' ) && REST_REQUEST ) {
			$show = false;

//			add_filter( 'jetpack_sharing_display_markup', '__return_empty_string' );
		}

		return $show;
	}
}

ETH_REST_API_Mods::register_hooks();