我有一个名为“book”的CPT，我想限制这本书的前端视图，就像特定角色用户只能view 这本书的内容来自前端，默认情况下任何人都可以看到来自前端的CPT帖子，我已经试过了capabilities 和map_meta_cap 但没有得到预期的结果。

CPT代码：

$args = array( 
    \'labels\' => $labels,
    \'hierarchical\' => true,
    \'description\' => \'test book\',
    \'supports\' => array( \'title\', \'editor\', \'author\'),
    \'public\' => true,
    \'show_ui\' => true,
    \'show_in_menu\' => true,
    \'show_in_nav_menus\' => true,
    \'publicly_queryable\' => true,
    \'has_archive\' => true,
    \'query_var\' => true,
    \'rewrite\' => true,
    \'capability_type\' => array(\'book\', \'books\'),
    \'capabilities\' => array(
       \'edit_post\' => \'edit_book\',
       \'edit_posts\' => \'edit_books\',
       \'edit_others_posts\' => \'edit_others_books\',
       \'publish_posts\' => \'publish_books\',
       \'read_post\' => \'read_book\',
       \'read_private_posts\' => \'read_private_books\',
       \'delete_post\' => \'delete_book\'
    )
);
register_post_type( \'book\', $args );

功能：

      // "lite_user" is a custom user role to manage book
    $roles = array( get_role(\'lite_user\') );
    foreach($roles as $role) {
      if($role) {
        $role->add_cap(\'read\');
        $role->add_cap(\'edit_book\');
        $role->add_cap(\'read_book\');
        $role->add_cap(\'delete_book\');
        $role->add_cap(\'edit_books\');
        $role->add_cap(\'edit_others_books\');
        $role->add_cap(\'publish_books\');
        $role->add_cap(\'read_private_books\');
      }
    }

根据此代码，任何公众都可以从前端查看/访问这些书籍，但我想限制这一点，lite_user 角色用户只能从前端查看/访问书籍。

function filter_the_content( $content ) {

   // Check post type is book
   // and that the current user is not lite user
   if (get_post_type() == \'book\' 
        && ! current_user_can( \'read_book\' ) ) { 

        // return a message in place of the content
        return \'Why do you want to see this book? You can\\\'t read!\';
    }

    // otherwise, show content
    return $content;

}

add_filter( \'the_content\', \'filter_the_content\' );