mercator.php

<?php
/**
 * Mercator
 *
 * WordPress multisite domain mapping for the modern era.
 *
 * @package Mercator
 */

namespace Mercator;

use WP_CLI;

/**
 * Current version of Mercator.
 */
const VERSION = '0.1';

require __DIR__ . '/class-mapping.php';
require __DIR__ . '/class-network-mapping.php';
require __DIR__ . '/multinetwork.php';
require __DIR__ . '/sso.php';
require __DIR__ . '/sso-multinetwork.php';

if ( defined( 'WP_CLI' ) && WP_CLI ) {
	require_once __DIR__ . '/inc/cli/class-mapping-command.php';
	require_once __DIR__ . '/inc/cli/class-network-mapping-command.php';
}

// Allow skipping bootstrap checks if you *really* know what you're doing.
// This lets Mercator run after muplugins_loaded, which you might need if you're
// doing unit tests.
if ( defined( 'MERCATOR_SKIP_CHECKS' ) && MERCATOR_SKIP_CHECKS ) {
	startup();
}
else {
	run_preflight();
}

/**
 * Perform preflight checks for Mercator
 *
 * Checks that we can actually run Mercator, then attaches the relevant actions
 * and filters to make it useful.
 */
function run_preflight() {
	// Are we installing? Bail if so.
	if ( defined( 'WP_INSTALLING' ) ) {
		return;
	}

	// Are we still in sunrise stage?
	if ( did_action( 'muplugins_loaded' ) ) {
		warn_with_message( 'Mercator must be loaded in your <code>sunrise.php</code>. Check out the <a href="https://github.com/humanmade/Mercator/wiki/Installation">installation instructions</a>.' );
		return;
	}

	// Are we actually on multisite?
	if ( ! is_multisite() ) {
		warn_with_message( 'Mercator requires WordPress to be in <a href="http://codex.wordpress.org/Create_A_Network">multisite mode</a>.' );
		return;
	}

	// Are we running a good version of WP?
	if ( ! function_exists( 'get_site_by_path' ) ) {
		warn_with_message( 'Mercator requires <a href="https://wordpress.org/download/">WordPress 3.9</a> or newer. Update now.' );
		return;
	}

	// M: We have clearance, Clarence.
	// O: Roger, Roger. What's our Vector Victor?
	startup();
}

/**
 * Attach Mercator into WordPress
 *
 * Imagine this as attaching the strings to the puppet.
 */
function startup() {
	// Define the table variables
	if ( empty( $GLOBALS['wpdb']->dmtable ) ) {
		$GLOBALS['wpdb']->dmtable = $GLOBALS['wpdb']->base_prefix . 'domain_mapping';
		$GLOBALS['wpdb']->ms_global_tables[] = 'domain_mapping';
	}

	// Ensure cache is shared
	wp_cache_add_global_groups( array( 'domain_mapping', 'network_mapping' ) );

	// Actually hook in!
	add_filter( 'pre_get_site_by_path', __NAMESPACE__ . '\\check_domain_mapping', 10, 2 );
	add_action( 'admin_init', __NAMESPACE__ . '\\load_admin', -100 );
	add_action( 'delete_blog', __NAMESPACE__ . '\\clear_mappings_on_delete' );
	add_action( 'muplugins_loaded', __NAMESPACE__ . '\\register_mapped_filters', -10 );

	// Add CLI commands
	if ( defined( 'WP_CLI' ) && WP_CLI ) {
		WP_CLI::add_command( 'mercator mapping', __NAMESPACE__ . '\\CLI\\Mapping_Command' );
		WP_CLI::add_command( 'mercator network-mapping', __NAMESPACE__ . '\\CLI\\Network_Mapping_Command' );
	}

	/**
	 * Fired after Mercator core has been loaded
	 *
	 * Hook into this to handle any add-on functionality.
	 */
	do_action( 'mercator_load' );
}

/**
 * Warn the user via the admin panels.
 *
 * @param string $message Message to use in the warning.
 */
function warn_with_message( $message ) {
	add_action( 'all_admin_notices', function () use ( $message ) {
		echo '<div class="error"><p>' . $message . '</p></div>';
	} );
}

/**
 * Check if a domain has a mapping available
 *
 * @param stdClass|null $site Site object if already found, null otherwise
 * @param string $domain Domain we're looking for
 * @return stdClass|null Site object if already found, null otherwise
 */
function check_domain_mapping( $site, $domain ) {
	// Have we already matched? (Allows other plugins to match first)
	if ( ! empty( $site ) ) {
		return $site;
	}

	global $wpdb;

	// Grab both WWW and no-WWW
	if ( strpos( $domain, 'www.' ) === 0 ) {
		$www = $domain;
		$nowww = substr( $domain, 4 );
	}
	else {
		$nowww = $domain;
		$www = 'www.' . $domain;
	}

	$mapping = Mapping::get_by_domain( array( $www, $nowww ) );
	if ( empty( $mapping ) || is_wp_error( $mapping ) ) {
		return $site;
	}

	/**
	 * Determine whether a mapping should be used
	 *
	 * Typically, you'll want to only allow active mappings to be used. However,
	 * if you want to use more advanced logic, or allow non-active domains to
	 * be mapped too, simply filter here.
	 *
	 * @param boolean $is_active Should the mapping be treated as active?
	 * @param Mapping $mapping Mapping that we're inspecting
	 * @param string $domain
	 */
	$is_active = apply_filters( 'mercator.use_mapping', $mapping->is_active(), $mapping, $domain );

	// Ignore non-active mappings
	if ( ! $is_active ) {
		return $site;
	}

	// Fetch the actual data for the site
	$mapped_site = $mapping->get_site();
	if ( empty( $mapped_site ) ) {
		return $site;
	}

	// Note: This is only for backwards compatibility with WPMU Domain Mapping,
	// do not rely on this constant in new code.
	defined( 'DOMAIN_MAPPING' ) or define( 'DOMAIN_MAPPING', 1 );
	return $mapped_site;
}

/**
 * Check the Mercator mapping table
 *
 * @return string|boolean One of 'exists' (table already existed), 'created' (table was created), or false if could not be created
 */
function check_table() {
	global $wpdb;

	$schema = "CREATE TABLE {$wpdb->dmtable} (
		id bigint(20) NOT NULL auto_increment,
		blog_id bigint(20) NOT NULL,
		domain varchar(255) NOT NULL,
		active tinyint(4) default 1,
		PRIMARY KEY  (id),
		KEY blog_id (blog_id,domain,active),
		KEY domain (domain)
	);";

	if ( ! function_exists( 'dbDelta' ) ) {
		if ( ! is_admin() ) {
			return false;
		}

		require_once ABSPATH . 'wp-admin/includes/upgrade.php';
	}

	// Ensure we always try to create this, regardless of whether we're on the
	// main site or not. dbDelta will skip creation of global tables on
	// non-main sites.
	$offset = array_search( 'domain_mapping', $wpdb->ms_global_tables );
	if ( ! empty( $offset ) ) {
		unset( $wpdb->ms_global_tables[ $offset ] );
	}
	$result = dbDelta( $schema );
	$wpdb->ms_global_tables[] = 'domain_mapping';

	if ( empty( $result ) ) {
		// No changes, database already exists and is up-to-date
		return 'exists';
	}

	return 'created';
}

/**
 * Load administration functions
 *
 * We do this here rather than just including it to avoid extra load on
 * non-admin pages.
 */
function load_admin() {
	require_once __DIR__ . '/admin.php';
	require_once __DIR__ . '/inc/admin/class-alias-list-table.php';
}

/**
 * Clear mappings for a site when it's deleted
 *
 * @param int $site_id Site being deleted
 */
function clear_mappings_on_delete( $site_id ) {
	$mappings = Mapping::get_by_site( $site_id );

	if ( empty( $mappings ) ) {
		return;
	}

	foreach ( $mappings as $mapping ) {
		$error = $mapping->delete();

		if ( is_wp_error( $error ) ) {
			$message = sprintf(
				__( 'Unable to delete mapping %d for site %d', 'mercator' ),
				$mapping->get_id(),
				$site_id
			);
			trigger_error( $message, E_USER_WARNING );
		}
	}
}

/**
 * Register filters for URLs, if we've mapped
 */
function register_mapped_filters() {
	$current_site = $GLOBALS['current_blog'];
	$real_domain = $current_site->domain;
	$domain = $_SERVER['HTTP_HOST'];

	if ( $domain === $real_domain ) {
		// Domain hasn't been mapped
		return;
	}

	// Grab both WWW and no-WWW
	if ( strpos( $domain, 'www.' ) === 0 ) {
		$www = $domain;
		$nowww = substr( $domain, 4 );
	}
	else {
		$nowww = $domain;
		$www = 'www.' . $domain;
	}

	$mapping = Mapping::get_by_domain( array( $www, $nowww ) );
	if ( empty( $mapping ) || is_wp_error( $mapping ) ) {
		return;
	}

	$GLOBALS['mercator_current_mapping'] = $mapping;
	add_filter( 'site_url', __NAMESPACE__ . '\\mangle_url', -10, 4 );
	add_filter( 'home_url', __NAMESPACE__ . '\\mangle_url', -10, 4 );

	// If on network site, also filter network urls
	if ( is_main_site() ) {
		add_filter( 'network_site_url', __NAMESPACE__ . '\\mangle_url', -10, 3 );
		add_filter( 'network_home_url', __NAMESPACE__ . '\\mangle_url', -10, 3 );
	}
}

/**
 * Mangle the home URL to give our primary domain
 *
 * @param string $url The complete home URL including scheme and path.
 * @param string $path Path relative to the home URL. Blank string if no path is specified.
 * @param string|null $orig_scheme Scheme to give the home URL context. Accepts 'http', 'https', 'relative' or null.
 * @param int|null $site_id Blog ID, or null for the current blog.
 * @return string Mangled URL
 */
function mangle_url( $url, $path, $orig_scheme, $site_id = 0 ) {
	if ( empty( $site_id ) ) {
		$site_id = get_current_blog_id();
	}

	$current_mapping = $GLOBALS['mercator_current_mapping'];
	if ( empty( $current_mapping ) || $site_id !== (int) $current_mapping->get_site_id() ) {
		return $url;
	}

	// Replace the domain
	$domain = parse_url( $url, PHP_URL_HOST );
	$regex = '#^(\w+://)' . preg_quote( $domain, '#' ) . '#i';
	$mangled = preg_replace( $regex, '${1}' . $current_mapping->get_domain(), $url );

	return $mangled;
}