Making Customizer Work with Domain Mapping on Multisite (WordPress Network)

Issue is resolved – posting problem + code solution in case anyone else has the same issue or should the maintainer choose to update the plugin.

Issue:
On a site that I had a domain, mapped as primary, I ran into problems using Customizer. When I would load Customizer the left panel would display all the customizer options/settings but the iFrame preview on the right would not load, or in my local environment, would load an error message: Non-existent changeset UUID.

Settings:

My Admin > Network > Settings > Domain Mapping options were as follows:

1 [ ] Remote Login
2 [x] Permanent redirect (better for your blogger’s pagerank)
3 [x] User domain mapping page
4 [x] Redirect administration pages to site’s original domain (remote login disabled if this redirect is disabled)
5 [ ] Disable primary domain check. Sites will not redirect to one domain name. May cause duplicate content issues.

Debugging:
What was happening was the customizer iFrame was trying to load subdomain.example.com but was redirecting to the primary domain.

Solution:

I observed logic in the domain-mapping.php file in the function redirect_to_mapped_domain() that was supposed to prevent redirecting customizer requests but it appears the way to identify customizer has changed since then. I added the following condition:

// But really - don't redirect theme customizer (WP ?)
if ( isset( $_GET['customize_changeset_uuid'] ) ){
	return;
}

That complete function now looks like this:

function redirect_to_mapped_domain() {
	global $current_blog, $wpdb;

	// don't redirect the main site
	if ( is_main_site() )
		return;
	// don't redirect post previews
	if ( isset( $_GET['preview'] ) && $_GET['preview'] == 'true' )
		return;

	// don't redirect theme customizer (WP 3.4)
	if ( isset( $_POST['customize'] ) && isset( $_POST['theme'] ) && $_POST['customize'] == 'on' )
		return;

	// But really - don't redirect theme customizer (WP ?)
	if ( isset( $_GET['customize_changeset_uuid'] ) ){
		return;
	}

	$protocol = is_ssl() ? 'https://' : 'https://';
	$url = domain_mapping_siteurl( false );
	if ( $url && $url != untrailingslashit( $protocol . $current_blog->domain . $current_blog->path ) ) {
		$redirect = get_site_option( 'dm_301_redirect' ) ? '301' : '302';
		if ( ( defined( 'VHOST' ) && constant( "VHOST" ) != 'yes' ) || ( defined( 'SUBDOMAIN_INSTALL' ) && constant( 'SUBDOMAIN_INSTALL' ) == false ) ) {
			$_SERVER[ 'REQUEST_URI' ] = str_replace( $current_blog->path, '/', $_SERVER[ 'REQUEST_URI' ] );
		}
		header( "Location: {$url}{$_SERVER[ 'REQUEST_URI' ]}", true, $redirect );
		exit;
	}
}

Now I can use customizer both locally and live both with and without a domain mapped to the site I am trying to customize.

• This topic was modified 5 years, 9 months ago by Terri Ann.
• This topic was modified 5 years, 9 months ago by Terri Ann. Reason: Fixing name/keywords to anyone else having this problem can find the solution