Want to hide some categories from the categories meta box in the post editor for the two specific user roles

Question

Recently, I am customizing the COLORMag theme in WordPress. I want to make my site as a multi-author website where random people will register and write. But as my theme's homepage shows all the posts by categories, so only I want to control which categories post to show on the homepage. To do this, I have to restrict some categories from the meta box so that only I can select which post to show in that category. I have created two custom user roles by Publishpress capabilities plugin.

Two of them are "Authors under review" and "Publisher". The authors under review cannot post directly to the homepage, but publishers can do. Now, I want to restrict some specific categories for both of them to select from the meta box while posting content. But the categories will show in my editor pannel as a super admin and the posts of that category will be visible to all. I hope I have been able to explain the problem. The problem is so urgent to be solved. And if you can give me the custom code with explanation and instruction then it will be highly appreciated as I am so new in coding. Thanks in advance.

N.B: There was a plugin in the Wordpress directories to restrict categories. But that plugin has been removed from the Wordpress due to security reason.

Answer 1

After searching a lot over the web I found a solution, so I am answering my own question. I hope it might help others. you can pass in the ids of categories you want to hide as an array, and then paste this in your functions.php file. It will work in the new editor. All categories will be shown for administrators.

Don't forget to customize the values in the $exclude_array = array("5","6","7","1");

function hide_categories_for_specific_user( $exclusions, $args ){

if (!current_user_can('manage_options') ) {

   // IDs of terms to be excluded
   $exclude_array = array("5","6","7","1"); // CHANGE THIS TO IDs OF YOUR TERMS


   // Generation of exclusion SQL code
   $exterms = wp_parse_id_list( $exclude_array );
   foreach ( $exterms as $exterm ) {
           if ( empty($exclusions) )
                   $exclusions = ' AND ( t.term_id <> ' . intval($exterm) . ' ';
           else
                   $exclusions .= ' AND t.term_id <> ' . intval($exterm) . ' ';
   }

   // Closing bracket
   if ( !empty($exclusions) )
       $exclusions .= ')';

   // Return our SQL statement
   return $exclusions;

  }
}

 // Finally hook up our filter
 add_filter( 'list_terms_exclusions', 'hide_categories_for_specific_user', 10, 2 );