在WP站点中过滤插件

Question

我在function.php中添加了一些代码来在我的WP站点中创建一些过滤器。 该脚本如下：

$GLOBALS['my_query_filters'] = array( 
    'field_1'   => 'forma', 
    'field_2'   => 'posa',
    'field_3'   => 'conduttore',
    'field_4'   => 'isolante',
    'field_5'   => 'raggio_minimo_di_curvatura',
    'field_6'   => 'guaina',
    'field_7'   => 'marchiatura',
    'field_8'   => 'tensione_di_esercizio',
    'field_9'   => 'temp_max_esercizio',
    'field_10'  => 'temp_min_di_inst',
    'field_11'  => 'temp_max_corto'
);


// action
add_action('pre_get_posts', 'my_pre_get_posts', 10, 1);

function my_pre_get_posts( $query ) {

    // bail early if is in admin
    if( is_admin() ) {
        return;
    }   

    // get meta query
    $meta_query = $query->get('meta_query');


    // loop over filters
    foreach( $GLOBALS['my_query_filters'] as $key => $name ) {

        // continue if not found in url
        if( empty($_GET[ $name ]) ) {

            continue;

        }


        // get the value for this filter
        // eg: http://www.website.com/events?city=melbourne,sydney
        $value = explode(',', $_GET[ $name ]);


        // append meta query
        $meta_query[] = array(
            'key'       => $name,
            'value'     => $value,
            'compare'   => 'IN',
        );

    } 


    // update meta query
    $query->set('meta_query', $meta_query);

}

目前，此代码仅显示10个空行，但有任何复选框或过滤器名称。

你能帮助我吗？