Fix Images not render from CDN while change upload path on MU site

smush-support-cdn-for-older-blogs-dir-mu-site.php

<?php
/**
 * Plugin Name: [Smush Pro] - Support CDN for older "blogs.dir" multisite
 * Description: [Smush Pro] - Support CDN for older "blogs.dir" multisite - required Smush >= 3.5
 * Task: 0/11289012348292/1161674459914571 - 1151490191545756
 * Author: Thobk @ WPMUDEV
 * Author URI: https://premium.wpmudev.org
 * License: GPLv2 or later
 */
if ( ! defined( 'ABSPATH' ) ) { exit; } elseif ( defined( 'WP_CLI' ) && WP_CLI ) { return; }

add_action( 'after_setup_theme', 'wpmudev_smpro_support_cdn_for_older_blogs_mu_site_func', 100 );

function wpmudev_smpro_support_cdn_for_older_blogs_mu_site_func() {
	if( defined('WP_SMUSH_VERSION') && ( class_exists( 'Smush\WP_Smush' ) || class_exists( 'WP_Smush' ) ) ){
		if( ! Smush\Core\Settings::get_instance()->get('cdn') || ! is_multisite() ) return;
		class WPMUDEV_Smush_Fix_Blog_Dir{
			private static $_original_domains;
			public function __construct(){
				add_filter( 'smush_filter_generate_cdn_url', array( $this, 'add_site_path_to_image_source') );
			}


			public function add_site_path_to_image_source( $src ){
				return str_replace(network_site_url(), '', str_replace(get_site_url(), rtrim($this->get_original_siteurl(),'/'), $src) );
			}

			/**
			 * Get original domain from siteurl value.
			 * @return bool|null|string
			 */
			public function get_original_siteurl( $blog_id = false ) {
				// If no blog id is passed, then take current one
				if ( ! $blog_id ) {
					$blog_id = get_current_blog_id();
				}
				// Check if we have already found original domain for the blog.
				if ( isset( self::$_original_domains[ $blog_id ] ) ) {
					return self::$_original_domains[ $blog_id ];
				} else {
					global $wpdb;
					// Get the site url.
					$site_url = $wpdb->get_var( sprintf(
						"SELECT option_value FROM %s WHERE option_name = 'siteurl'",
						$wpdb->options
					) );
					// If a value found, store the value and return.
					if ( ! empty( $site_url ) ) {
						// Store to cache.
						self::$_original_domains[ $blog_id ] = $site_url;

						return $site_url;
					}
				}

				return false;
			}
		}
		$run = new WPMUDEV_Smush_Fix_Blog_Dir();
	}
}