WP Multisite with Domain Mapping : Preventing User Access to Dashboard

Question

I have a theme being used by a sub-folder multisite and a domain-mapped multi site.

E.g.

mywpsite.com/site1

mywpsite.com/site2

www.site2.com (leads to the above)

I have this snippet of code in my functions.php file

function my_wp_admin_ban(){
if( !current_user_can('activate_plugins') ){
wp_redirect( get_bloginfo('url') );
exit;
}
}

add_action('admin_init','my_wp_admin_ban');

This successfully prevents members of site1 from access the admin (wp-admin) dashboard area.

This code does not, however, seem to work for site2.

Instead, those users are shown a "You do not have sufficient permissions to access this page." error message.

Tried everything I can think of including different ways of doing the same thing I.e. How to redirect non admins to homepage if trying to view mysite.com/wp-admin/? and How do I remove dashboard access from specific user roles?

What can I do to ensure all users (non admin) of the multisite are redirected away from the dashboard area?

Answer 1

The file functions.php is not the place to run this kind of code. See Where do I put the code snippets I found here or somewhere else on the web?

You can use a Must Use plugin or make a simple one and Network Activate.

It would go like this:

<?php
/* Plugin Name: Only admins on dashboard */

add_action( 'admin_init', 'admin_ban_wpse_105863' );

function admin_ban_wpse_105863()
{
    if( !current_user_can( 'activate_plugins' ) ){
        wp_redirect( site_url() );
        exit;
    }
}

The documentation for the function get_bloginfo has recommended alternatives for many cases. The site_url function takes care of using the current blog URL.

---

[update]
The only place where the error message ...permissions to access... appears is in the file wp-admin/includes/menu.php. And it has an useful hook:

add_action( 'admin_page_access_denied', 'denied_ban_wpse_105863' );

function denied_ban_wpse_105863()
{
    wp_redirect( site_url() );
    exit;
}