WordPress REST API 增加缩略图地址

WordPress REST API里默认只返回了特色图片的id：featured_media，却没有返回对应的图片地址。在页面里根据id来查找对应的图片很麻烦，因此需要增加一个新的字段 featured_image_url 来直接返回对应的特色图片。

functions.php 中添加方法

#-----------------------------------------------------------------#
# API中添加特色图片
#-----------------------------------------------------------------#
function post_fetured_image_json( $data, $post, $context ) {
	$featured_image_id = $data -> data['featured_media']; // 获取图片ID
	$featured_image_url = wp_get_attachment_image_src( $featured_image_id, 'original' ); // 获取图片地址

	if( $featured_image_url ) {
		$data->data['featured_image_url'] = $featured_image_url[0];
	}

	return $data;
}
add_filter( 'rest_prepare_post', 'post_fetured_image_json', 10, 3 );