WordPress Plugin Uninstall File Template

<?php
/*
* Uninstall WordPress Plugin
*
* @package: Test Plugin
*/

// Define plugin options, custom post types and custom taxonomies to remove.
$opt = array( 'my_options' );
$cpt = array( 'book' );
$tax = array( 'genre', 'writer' );


// Call uninstall cleanup method.
WP_Plugin_Janitor::cleanup( $opt, $cpt, $tax );


// Class containing cleanup and authorize methods.
class WP_Plugin_Janitor {

    public function cleanup( $opt = NULL, $cpt = NULL, $tax = NULL ) {
        // Perform security checks.
        if( self::authorize() == TRUE ) {

            // Remove plugin options from wp_options database table.
            if( $opt ) {
                foreach( $opt as $option ) {
                    delete_option( $option );
                }
            }

            // Remove plugin-specific custom post type entries.
            if( $cpt ) {
                $entries = get_posts( array( 'post_type' => $cpt ) );
                foreach( $entries as $entry ) {
                    wp_delete_post( $entry->ID, TRUE );
                }
            }

            // Remove plugin-specific custom taxonomies and terms.
            if( $tax ) {
                global $wp_taxonomies;
                foreach( $tax as $taxonomy ) {
                    $terms = get_terms( $taxonomy, array( 'get ' => 'all' ) ); // NOTE: get_terms doesn't seem to work during uninstall
                    foreach( $terms as $term ) {
                        wp_delete_term( $term->term_id, $taxonomy );
                    }
                    unset( $wp_taxonomies[$taxonomy] );
                }
            }

        }
    }

    public function authorize() {
        // No direct access from outside of WordPress.
        if( !function_exists( 'is_admin' ) ) {
            header( 'Status: 403 Forbidden' );
            header( 'HTTP/1.1 403 Forbidden' );
            exit();
        }

        // User must be logged in to uninstall plugin.
        if( !is_user_logged_in() ) {
            wp_die( 'You must be logged in to run this script.' );
        }

        // User must have permission to uninstall plugin.
        if( !current_user_can( 'install_plugins' ) ) {
            wp_die( 'You do not have permission to run this script.' );
        }

        // Authorize uninstall.
        return TRUE;
    }
}
?>