I already searched here and there but couldn't find anything definitive.

I have WordPress multisite and I have a plugin (activated on each site) which requires to set a slug parameter in wp-config.php.

Unfortunately each site of the network requires a different slug parameter.

I'd like to know if it is possible to put an if statement in wp-config.php in order to define these parameters based on $_SERVER['HTTP_HOST'] variable.

Code is the following:

if ( stristr( $_SERVER['HTTP_HOST'], 'site.com' ) ) {

    define('ABC_PRODUCT_SLUG', 'slug-for-en');

elseif ( stristr( $_SERVER['HTTP_HOST'], 'de.site.com' ) )
    define('ABC_PRODUCT_SLUG', 'slug-for-de');

Is that possible and reliable? Are there any possible drawbacks?


  • Yes, this is possible and reliable – kero Jan 29 '18 at 17:18
  • 3
    a plugin that requires wp-config changes? just don't use it. Maybe you should actually ask a question about your problem instead of about the only solution you see ;) In theory you should do this can of code in a "must use" plugin. The config file is not something you should modify if you have any alternative as the impact of breaking it during modification is just too big – Mark Kaplun Jan 29 '18 at 17:21
  • Yes, this is possible and perfectly reliable. I have done this for a long time as part of my standard WP install by defining a SITE_ENVIRONMENT constant for local | staging | live and have variable settings dependent on the environment. Ideally you would define the constant elsewhere (and then include/fetch it) so that you can still push your wp-config between environments without overwriting the environment value. Note: Some hosts - especially dedicated Wordpress managed hosts - don't let you manage wp-config. They always supply workarounds though. – onebc Jan 29 '18 at 17:28
  • Note that ` $_SERVER['HTTP_HOST']` is not defined on the command line, e.g. when using WP-CLI. – swissspidy Jan 29 '18 at 17:33
  • Though it's possible and reliable, but just don't do it. Instead, you can create site specific plugins (or for the whole network) and define those constants there. – Abhik Jan 29 '18 at 17:59

Following on from the comments thread...

Here's a method I've used for a long time for handling the 'not ideal' scenario of different configurations between environments. The following is a heavily cut-down representation of wp-config.php but it demonstrates the idea...

  * The base configurations of the WordPress.
  * This file has the following configurations: MySQL settings, Table Prefix,
  * Secret Keys, WordPress Language, and ABSPATH. You can find more information
  * by visiting {@link http://codex.wordpress.org/Editing_wp-config.php Editing
  * wp-config.php} Codex page. You can get the MySQL settings from your web host.
  * This file is used by the wp-config.php creation script during the
  * installation. You don't have to use the web site, you can just copy this file
  * to "wp-config.php" and fill in the values.
  * @package WordPress

/** Environment: LOCAL || STAGING || LIVE **/
define('BCUK_SITE_ENV', 'LOCAL');

/** System/CMS defaults **/
e.g. settings that are common across all environments

e.g. different db settings, memory limits, paths, etc.

elseif (BCUK_SITE_ENV == "STAGING"):
e.g. different db settings, memory limits, paths, etc.

e.g. different db settings, memory limits, paths, etc.


// Remaining wp-config bits go here e.g. salts, lang settings, etc

As you can see I prefer to assume that 'else' means the live settings, just for safety's sake.

I have also used versions of this method where the definition of the environment is actually in a separate file that is included e.g. replacing define('BCUK_SITE_ENV', 'LOCAL'); with an include statement that pulls in a file (something like 'environment_config.inc.php') in which there is just one line that is used to change the environment constant. That way you can always push your wp-config.php between environments without actually affecting which environment is currently configured.

In all the above, you could easily adapt it to either base your logic directly on the value of $_SERVER['HTTP_HOST'] or to configure your environment variable/constant on the value of $_SERVER['HTTP_HOST'].

Hope that all makes sense. It's definitely not the only way, but hopefully it demonstrates that it is definitely a robust and workable method. Whether it works for your particular plugin development scenario only you will know.

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