A simple MU plugin that updates the primary domain on WordPress Network installations. It was primarily created for development and staging environments to make it easier when you sync data from a production site.

This plugin is in early stages of development. Use are your own risk. This plugin is useless to you if you are not running a WordPress Network in Subdomain mode!

Consider this alpha-quality code!

Let's say you run a WordPress Network of sub-domains. If you did a MySQL dump from your production server (example.com) and then imported to your staging (staging.example.com) or local development (example.local) instance, the primary domain would no longer match the environment.

This plugin checks to see if the primary domain changed, and if so, updates the sub-sites and relevant database fields.

For example, I use Local by Flywheel for local WordPress development:

1. Create a local WordPress multisite instance.
2. Copy necessary file assets (plugins, themes, uploads, etc) from the remote site.
3. Add this mu-plugin to your local instance's mu-plugins directory.
4. Define the appropriate constants in wp-config.php.

Now, each time that you import MySQL dumps from your remote server to your local development database, this plugin will update the primary network and sub-sites to your local domain.

NB! This plugin is only intended to be used in staging and development environments! It is not intended to be run on production servers as it will incur a performance hit. You can try to use it to rename the primary domain on a production instance (create a MySQL backup first!), but once it's run and the domains are renamed, you should remove the plugin.

To install, simply download the network-subdomain-updater.php file and place it in your wp-content/mu-plugins directory (create one if it doesn't exist). Don't copy the other files - they are not necessary.

Simply define a NETWORK_LOCAL_DOMAIN constant in the wp-config.php for each instance you wish to use it on.

This plugin is configured with constants that you defined in your development/staging environments wp-config.php files.

SITE_ID_CURRENT_SITE (required)

define( 'SITE_ID_CURRENT_SITE', 1 ); 

NETWORK_LOCAL_DOMAIN (required)

Examples:

define( 'NETWORK_LOCAL_DOMAIN', 'mylocaldomain.local' ); // Example local development domain define( 'NETWORK_LOCAL_DOMAIN', 'staging.example.com' ); // Example staging instance domain 

NOBLOGREDIRECT (required)

define( 'NOBLOGREDIRECT', true ); // Must be set to true! 

NETWORK_LOCAL_DOMAIN_SCHEME

Examples:

define( 'NETWORK_LOCAL_DOMAIN_SCHEME', 'https' ); // Prefix site URLs with: https define( 'NETWORK_LOCAL_DOMAIN_SCHEME', 'http' ); // Prefix site URLs with: http 

(This allows you to force HTTP or HTTPS on updated site URLs, depending on what your LAMP environment supports. If not defined or set to false, original URL prefixes will be preserved.)

WP_ADMIN_EMAIL

If specified, changes the admin_mail value in wp_options, useful for debugging:

define( 'WP_ADMIN_EMAIL', 'you@example.com' ); 

(This is irrelevant if you are using something like MailHog to intercept e-mails.)

NETWORK_LOCAL_UPDATE_NOTIFY

If defined, sends a notification e-mail stating that an update was performed.

Send to admin_email using plugin defaults:

define( 'NETWORK_LOCAL_UPDATE_NOTIFY', true ); 

Send to specific e-mail address:

define( 'NETWORK_LOCAL_UPDATE_NOTIFY', 'you@example.com' ); 

PHP 7 or higher Options:

define( 'NETWORK_LOCAL_UPDATE_NOTIFY', [ 'email' => 'you@yourdomain.com', 'subject' => 'Site sync!', 'message' => 'This space intentionally left blank.' ] ); 

Let's assume the following:

• Your production sites are at: *.example.com
• Your staging environment sites are at: *.staging.example.com
• Your development environment sites are at: *.example.local

In your staging environment's wp-config.php, you might define NETWORK_LOCAL_DOMAIN as follows:

define( 'NETWORK_LOCAL_DOMAIN', 'staging.example.com' ); 

In your development environment's wp-config.php, you might define NETWORK_LOCAL_DOMAIN as follows:

define( 'NETWORK_LOCAL_DOMAIN', 'example.local' ); 

Below is a typical example of the constants that you'd add/change in wp-config.php:

define( 'WP_HOME','https://mysite.local' ); define( 'WP_SITEURL','https://mysite.local' ); define( 'DOMAIN_CURRENT_SITE', 'mysite.local' ); define( 'NETWORK_LOCAL_DOMAIN', 'mysite.local' ); define( 'WP_ADMIN_EMAIL', 'webmaster@mysite.local' ); // Optional define( 'NOBLOGREDIRECT', true ); // Required 

Release changes are noted on the Releases page.

• Fixed order of operations issue