The mu_plugin_loaded WordPress PHP action is triggered once a single must-use (MU) plugin has loaded.
Usage
add_action('mu_plugin_loaded', 'my_mu_plugin_loaded_callback', 10, 1);
function my_mu_plugin_loaded_callback($mu_plugin) {
// your custom code here
}
Parameters
$mu_plugin(string): Full path to the plugin’s main file.
More information
See WordPress Developer Resources: mu_plugin_loaded
Examples
Logging MU plugin loading
Log the loading of MU plugins in a log file.
add_action('mu_plugin_loaded', 'log_mu_plugin_loaded', 10, 1);
function log_mu_plugin_loaded($mu_plugin) {
// Log the loaded MU plugin
error_log("MU plugin loaded: " . $mu_plugin);
}
Print MU plugin name in admin area
Display the name of the loaded MU plugin in the admin area.
add_action('mu_plugin_loaded', 'show_mu_plugin_name_in_admin', 10, 1);
function show_mu_plugin_name_in_admin($mu_plugin) {
if (is_admin()) {
// Extract the plugin directory name
$plugin_dir = basename(dirname($mu_plugin));
// Print the MU plugin name
echo 'Loaded MU plugin: ' . $plugin_dir . '<br>';
}
}
Check for a specific MU plugin
Detect if a specific MU plugin has been loaded.
add_action('mu_plugin_loaded', 'check_specific_mu_plugin', 10, 1);
function check_specific_mu_plugin($mu_plugin) {
$target_plugin = 'my-custom-plugin';
if (strpos($mu_plugin, $target_plugin) !== false) {
// Your custom code if the target plugin is loaded
}
}
Count loaded MU plugins
Count the number of loaded MU plugins.
add_action('mu_plugin_loaded', 'count_mu_plugins', 10, 1);
function count_mu_plugins($mu_plugin) {
static $plugin_count = 0;
$plugin_count++;
// Your custom code using $plugin_count
}
Display a message after a specific MU plugin is loaded
Show a custom message after loading a specific MU plugin.
add_action('mu_plugin_loaded', 'display_message_after_plugin_loaded', 10, 1);
function display_message_after_plugin_loaded($mu_plugin) {
$target_plugin = 'my-custom-plugin';
if (strpos($mu_plugin, $target_plugin) !== false) {
// Display a custom message
echo 'The ' . $target_plugin . ' MU plugin has been loaded successfully.';
}
}