Comments on: WordPress Plugin Dependency Checking

By: thomasb

thomasb — Mon, 11 Apr 2011 10:11:00 +0000

WordPress keeps track of active plugins in the `options` table.

SELECT * FROM wp_options WHERE option_name = ‘active_plugins’;

global $wpdb;
$active_plugins = get_option(‘active_plugins’, FALSE);
$depends = ‘nextgen-gallery/nggallery.php’;
if ( ! in_array($depends, $active_plugins)) {
die(“Required plugin, {$depends} could not be found, please activate it before continuing”);
}

By: thomasb

thomasb — Mon, 11 Apr 2011 10:10:20 +0000

WordPress keeps track of active plugins in the `options` table.

SELECT * FROM wp_options WHERE option_name = ‘active_plugins’;

By: Will Kemp

Will Kemp — Sun, 23 Jan 2011 06:16:52 +0000

Interesting and useful. Thanks for that!

By: Dell Sala

Dell Sala — Sun, 23 Jan 2011 02:56:14 +0000

Just implemented something very similar. Was hoping for something built into WP for this, but found nothing. This is the best solution I’ve found.

A couple minor improvements to the usability: Instead of die(), just return. This will stop execution of the file, but won’t kill the entire wordpress stack.

To notify the user add an admin notice:

if (/*PLUGIN-NOT-INSTALLED*/) {
add_action(‘admin_notices’, ‘dependency_error’);
return;
}

function dependency_error () {
echo ‘Required dependency is missing.’;
}

By: alex chousmith

alex chousmith — Tue, 12 Oct 2010 23:27:34 +0000

Hey, I found this post as I was searching for “how to figure out if a plugin is installed”. You have a great quick solution, but unfortunately I have found that many WP plugins are not good about cleaning up after themselves…

in the case where a user has at one point installed NextGen Gallery (or in my case, WP e-Commerce Plugin), but gave up on it and uninstalled/deleted it, the db tables often might not get removed correctly, and your test would show that the plugin is there when it really isnt any more.