Read this article to find out more about WordPress multitenancy. Bobcares, as a part of our WordPress Support Services, offers solutions to every query that comes our way.

WordPress Multitenancy

WordPress multitenancy refers to the use of the same WordPress code-base by several WordPress sites. Multitenancy enables independent WordPress sites to share a single code base.

How To Set Up WordPress Multitenancy?

To set up multitenancy, we use WordPress (version 3.4.1) in its directory. This was not web accessible and its wp-content directory is also deleted. Also, create two sites, with their web-accessible directories containing only the wp-content directory. Now let’s see the setup process.

Firstly, when symlinking all of the top-level files and directories in the tenant to the core, we may see a white screen. When we look at the error logs, we can see WordPress was not able to include

wp-config.phpCopy Code

. It uses the

__FILE__Copy Code

constant from PHP to carry out directory traversal. It turns out that before setting

__FILE__Copy Code

, PHP resolves the path by converting all symbolic links. WordPress then searched the core directory for

wp-config.phpCopy Code

. WordPress must search the tenant directory for

wp-config.phpCopy Code

. Here, symlinks worked. But PHP resolved paths preventing the core from including the tenant code.

The

wp-config.phpCopy Code

file’s function is to configure WordPress. So it seemed appropriate to use it. The code that was utilized

__FILE__Copy Code

only failed when referencing

wp-config.phpCopy Code

. Since

__FILE__Copy Code

refers to other core files, other core code using it needs to work as intended. In the end, the

wp-contentCopy Code

directory and the

wp-config.phpCopy Code

are the main references to the tenancy.

Since WordPress already includes a constant, configuring the

wp-contentCopy Code

directory is simple. We can change the

wp-contentCopy Code

directory’s location using the

WP_CONTENT_DIRCopy Code

function. The ability to modify this inside 

wp-config.phpCopy Code

gave this method much more credibility.

How to fix it?

The secret is to link the tenant’s

wp-config.phpCopy Code

file. All we have to do is make a

wp-config.phpCopy Code

file in the core to act as a stand-in. The tenant

wp-config.phpCopy Code

can then be included in the main

wp-config.phpCopy Code

file.

We use PHP’s super global

$_SERVER['DOCUMENT_ROOT']Copy Code

to find the tenant’s location. The server’s setup has already set this specific value. WordPress also makes use of this value. Therefore, there is no security risk. We may now symlink the other core files and folders after resolving the inclusion of the tenant

wp-config.phpCopy Code

issue.

The wp-config.php file in the core

<?php

/**

* The base configurations of the WordPress.

*

* ...

*

* @package WordPress

*/

// NOTE: this WordPress install is configured for multitenancy

require_once dirname($_SERVER['DOCUMENT_ROOT']) . '/wp-config.php';

/* That's all, stop editing! Happy blogging. */

/** Absolute path to the WordPress directory. */

if(!defined('ABSPATH'))

define('ABSPATH', dirname(__FILE__) . '/');

/** Sets up WordPress vars and included files. */

require_once(ABSPATH . 'wp-settings.php');

The wp-config.php file in the Tenant

<?php

/**

* The base configurations of the WordPress.

*

* ...

*

* @package WordPress

*/

// NOTE: file lives outside webroot for additional security

// modify the config file based on environment

if (strpos($_SERVER['HTTP_HOST'], 'local') !== false) {

$config_file = 'config/wp-config.dev.php';

} else {

$config_file = 'config/wp-config.prod.php';

}

$path = dirname(__FILE__) . '/';

require_once $path . $config_file;

/** Database Charset to use in creating database tables. */

define('DB_CHARSET', 'utf8');

/** The Database Collate type. Don't change this if in doubt. */

define('DB_COLLATE', '');

// ...

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Conclusion

The article explains WordPress Multitenancy in detail. We also include the setup guide from our Tech Support for Multitenancy.