Multisite & Multinetwork

How it can help you and how you can help it

1. Multisite Introduction, Benefits, Use Cases, Setup
2. Multinetwork Introduction, Benefits, Use Cases, Setup
3. Developer Best Practices History, Issues, Plugins
4. Gist

Multisite Introduction

Multisite Introduction

Multisite Benefits

• easy update management without a third-party tool
• sites can interact with each other directly (without a remote request)

Multisite Benefits

• common user management across the entire multisite
• sites can have their individual admins while a network admin has control over the entire network

Multisite Benefits

• plugins can be network-activated (so that they run on all sites)
• better user capabilities: network administrators manage plugins and themes while regular admins still have access to everything else

Multisite Use Cases

• outsourcing parts of a website (for example blog.example.com)
• managing clients that have multiple websites
• hosting client sites in one WordPress installation
• running a social network where users can create their own sites

Multisite Use Cases

Multisite Setup

Multinetwork Introduction

Multinetwork Introduction

Multinetwork Benefits

Why not just have a multisite?

Multinetwork Benefits

BECAUSE WAPUU SAY SO.

Multinetwork Benefits

• sites can be separated into groups of sites
• each network can have individual network admins, network-activated plugins etc.

Multinetwork Use Cases

Multinetwork Use Cases

Multinetwork Setup

Developer Best Practices History

• WordPress was not invented with Multisite and (especially) Multinetwork in mind
• Multisite started as „WordPress MU“ and was merged into WordPress Core in version 3.0 (see https://mu.wordpress.org/)
• therefore some things are not solved in an optimal way

Developer Best Practices History

• because of backwards compatibility, these naming conventions are used interchangeably in WordPress Core
  • everything new uses the current conventions
  • old code uses the old conventions

Developer Best Practices Issues

• when working with Multisite / Multinetwork, you might encounter minor issues or features you‘re missing (but everything can be fixed)
• methods to fix these:
  • write a must-use plugin or create your own sunrise.php (short-term solution)
  • contribute to WordPress Core and actually fix it at its base (long-term solution)

Developer Best Practices Issues

• a site like www.example.com is not properly redirected to when entering example.com
• the URL scheme is also not considered for possible redirections (HTTP vs HTTPS)

Developer Best Practices Issues

• What is the next step in the hierarchy, beyond networks? There is none.
• Any network admin can create new networks which is usually undesirable.

Developer Best Practices Issues

• Idea: a network manager (or global admin)

Developer Best Practices Issues

Developer Best Practices Plugins

Don't keep Multisite and Multinetwork out!

Supporting them in your plugin is very easy.
(usually it's only about activation/deactivation/uninstallation routines)

Developer Best Practices Plugins

function myplugin_activate( $network_wide ) {
	myplugin_install_table();
}

Bad Example: Multisite is not handled at all.

Developer Best Practices Plugins

function myplugin_activate( $network_wide ) {
	global $wpdb;

	if ( $network_wide ) {
		$site_ids = $wpdb->get_col(
			"SELECT blog_id FROM $wpdb->blogs"
		);
		foreach ( $site_ids as $site_id ) {
			switch_to_blog( $site_id );
			myplugin_install_table();
			restore_current_blog();
		}
	} else {
		myplugin_install_table();
	}
}

Bad Example: Multisite is handled, but Multinetwork is ignored.

Developer Best Practices Plugins

function myplugin_activate( $network_wide ) {
	global $wpdb;

	if ( $network_wide ) {
		$site_ids = $wpdb->get_col(
			"SELECT blog_id FROM $wpdb->blogs WHERE site_id = $wpdb->siteid"
		);
		foreach ( $site_ids as $site_id ) {
			switch_to_blog( $site_id );
			myplugin_install_table();
			restore_current_blog();
		}
	} else {
		myplugin_install_table();
	}
}

Good Example: Multisite and Multinetwork are handled.

Gist

• if this session got you interested, I‘d love for you to start playing around with Multisite (and Multinetwork)
• if you‘re a plugin developer, please make sure your code runs properly on Multisite/Multinetwork
• if you find issues with Multisite, consider contributing to the Multisite component in WordPress Core – it is a pretty small team, so your help will be much appreciated
• if you find issues with Multinetwork, consider helping out with the WP Multi Network plugin

Thank you!

Felix Arntz

Plugin Developer / Core Contributor / Freelancer

• felix-arntz.me
• profiles.wordpress.org/flixos90
• github.com/felixarntz
• twitter.com/felixarntz