WordPress Dropins

Plugins are pretty popular, since it is easy to adjust your blog or website to your liking with Plugins. Less popular are Dropins.

WordPress alows to replace some functions with Dropins. The list of possibilities isn’t big and not well documented. But I like to use Dropins to enhance the possibilties of caching, especially APC and Memcache. But also to adjust uploads, permalinks and similar things are a typical scenario for Dropins.

Most of the Plugins are in the WP Content Folder, normally wp-content or via constant WP_CONTENT_DIR or the URL in WP_CONTENT_URL is defined.
Example:

// Custom content directory
define( 'WP_CONTENT_DIR',  dirname( __FILE__ ) . '/wp-content' );
define( 'WP_CONTENT_URL',  'http://' . $_SERVER['HTTP_HOST'] . '/wp-content' );

I use this in my dev environment or at my clients project for example, since I can access Plugins via FTP in different ways. See my WordPress Starter Repo on Github for more solutions and hints about this topic.

Only Dropins, which get loaded with a language key, aren’t in this folder, instead they are in /wp-content/languages. Alternatively you can define the folder via the constant WP_LANG_DIR.
The Dropin for the German key de_DE takes that path. See the repo for read the source or find more information.

In Backend are Dropins listed since version 3.0, but only the following in the table and not the Dropin to the language key. Also you can not just deactivate or activate it via backend, that’s why Plugins are preferred for some solutions.

Below is a table with all Dropins I know or I have found. The possible Dropins are echoing via the function _get_dropins() .