我在这篇文章中找到了一个很好的解决方案：How to add wordpress username after url?

/*
Plugin Name: My Awesome Button
Description: The shortcode [my-awesome-button] will be replaced with the HTML code for a button for logged-in users and for guests it will be replaced with an empty string (so it will be removed). This will work for posts and pages.
Author: Nikolay Nikolov
Version: 1.0.0
*/

add_filter( \'the_content\', \'my_awesome_button_function\', 99999999999 );

function my_awesome_button_function( $content ) {
    if ( strpos( $content, \'[my-awesome-button]\' ) !== false ) {
        if ( is_user_logged_in() ) {
            $current_user = wp_get_current_user();
            $button_html = \'<a href="https://direktoriku.com/shopping/?user=\' . esc_attr( $current_user->user_login ) . \'"><button>Click me</button></a>\';
            $content = str_replace( \'[my-awesome-button]\', $button_html, $content );
        } else {
            $content = str_replace( \'[my-awesome-button]\', \'\', $content );
        }
    }
    return $content;
}

我唯一的问题是，该按钮仅在主页上处于活动状态，而在网站的所有其他页面（例如mydomain.com/documents）上处于非活动状态。

请你帮我把它修好。

非常感谢！

add_shortcode( \'my-awesome-button\', \'wp_my_awesome_bytton\' );
function wp_my_awesome_bytton( $atts ) {
    $button_html = \'\';
    if ( is_user_logged_in() ) {
            $current_user = wp_get_current_user();
            $button_html = \'<a href="https://direktoriku.com/shopping/?user=\' . esc_attr( $current_user->user_login ) . \'"><button>Click me</button></a>\';

    }
    return $button_html; 
}