CorePlugin Development

How to use the wordpress plugin register uninstall hook

By December 9, 2018 No Comments

How to use the register_uninstall_hook

It’s exciting to create your own wordpress plugin but installing your plugin is only one part. It’s critical to know how to use the register_uninstall_hook function to remove your plugin from the user’s computer. This code registers the uninstall hook that will be called when the user clicks on the uninstall link that calls for the plugin to uninstall itself. The link won’t be active unless the plugin hooks into the action.

The plugin should not run arbitrary code outside of functions, when registering the uninstall hook. In order to run using the hook, the plugin will have to be included, which means that any code laying outside of a function will be run during the uninstallation process. The plugin should not hinder the uninstallation process.

If the plugin can not be written without running code within the plugin, then the plugin should create a file named ‘uninstall.php’ in the base plugin folder. This file will be called, if it exists, during the uninstallation process bypassing the uninstall hook. The plugin, when using the ‘uninstall.php’ should always check for the ‘WP_UNINSTALL_PLUGIN’ constant, before executing.

register_uninstall_hook( string $file, callable $callback )

Parameters

$file

(string) (Required) Plugin file.

$callback

(callable) (Required) The callback to run when the hook is called. Must be a static method or function.

 

function register_uninstall_hook( $file, $callback ) {
    if ( is_array( $callback ) && is_object( $callback[0] ) ) {
        _doing_it_wrong( __FUNCTION__, __( 'Only a static class method or function can be used in an uninstall hook.' ), '3.1.0' );
        return;
    }
 
    /*
     * The option should not be autoloaded, because it is not needed in most
     * cases. Emphasis should be put on using the 'uninstall.php' way of
     * uninstalling the plugin.
     */
    $uninstallable_plugins = (array) get_option('uninstall_plugins');
    $uninstallable_plugins[plugin_basename($file)] = $callback;
 
    update_option('uninstall_plugins', $uninstallable_plugins);
}

Other uses

Uses Description
wp-includes/l10n.php: __()
wp-includes/functions.php: _doing_it_wrong()
wp-includes/plugin.php: plugin_basename()
wp-includes/option.php: update_option()
wp-includes/option.php: get_option()

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