How to create a wordpress widget that dynamically changes according to the page

Question

I am creating a plugin in which my custom sidebar widget changes content depending on the page it is loading on. One way to do this is

// Register and load the widget
function custom_register_widget() {
    register_widget( 'custom_widget' );
}

//trigger on every sidebar load
add_action('dynamic_sidebar', 'custom_register_widget' );

However, this calls the register_widget() on every page load ( thereby making changes to WordPress DB ), thus slowing the page speed.

Is there an efficient way to this?

Answer 1

register_widget() doesn't make any changes to the database. All it does is make a particular widget available to be used. It shouldn't be used on the dynamic_sidebar hook. It's supposed to be used on the widgets_init hook.

If you want the contents of a widget to change depending on the current page, then that logic needs to be in the widget itself, in the widget() method:

class My_Widget extends WP_Widget {
    public function __construct() {}

    public function widget( $args, $instance ) {
        if ( is_page() ) {
            $page_id = get_queried_object_id();

            echo get_the_title( $page_id );
        }
    }

    public function form( $instance ) {}

    public function update( $new_instance, $old_instance ) {}
}

That example will output the current page title, if you're viewing a page.